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Author Topic: Stratolaunch  (Read 58955 times)

Offline Creative

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Stratolaunch
« on: December 13, 2011, 02:22:02 pm »
http://www.gizmag.com/stratolaunch-systems-air-launch/20839/

Quote
...
Allen and Rutan's new company, Stratolaunch Systems, will be developing a mobile launch system consisting of three main components.
The first will be an enormous carrier aircraft, made by Rutan's company Scaled Composites. With a wingspan of over 380 feet (116 m), packing six 747 engines and weighing over 1.2 million pounds (544,311 kg), it will be the largest aircraft ever flown.
Mounted underneath the aircraft's SpaceShipOne-like twin bodies will be a multi-stage booster, which in turn will be attached to the spacecraft. Built by Space Exploration Technologies, this 490,000-pound (222,260-kg) booster will fire once it has been released from the aircraft, carrying the spacecraft into orbit.
The third component of the system will be a mating and integration system, which will allow the aircraft to safely carry and release its payload. It will be designed by aerospace engineering firm Dynetics.
The aircraft will be constructed in a dedicated Stratolaunch hangar, which will reportedly soon be under construction at the Mojave Air and Space Port. Hopefully, the first flight should be taking place within five years. According to the company, its air-launch-to-orbit system "will mean lower costs, greater safety, and more flexibility and responsiveness than is possible today with ground-based systems." Turnaround time between launches should also be much shorter than is currently possible, allowing for a larger number of launches within a given time period.
Once built, the aircraft will likely operate out of a large airport/spaceport, such as the Kennedy Space Center. It will require a runway at least 12,000 feet (3,658 m) long, and be able to fly to launch points up to 1,300 nautical miles (2,407 km) away...

http://stratolaunchsystems.com/

Offline Skyblazer

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Re: Stratolaunch
« Reply #1 on: December 13, 2011, 02:29:14 pm »
Two pics from the official site:

Offline AeroFranz

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Re: Stratolaunch
« Reply #2 on: December 13, 2011, 06:36:39 pm »

A couple of thoughts:


One, depending on what the wheeltrack ends up being on the mothership, it might be hard to find suitable airports. But then again you probably only need few airports since you can cruise to a designated launch area thousands of miles away.


Two, didn't Rutan say sometime ago something to the effect that Scaled had pioneered construction techniques for the WK1 wing spar that was "scalable to very large aircraft"? I guess this would be it.


There are plenty of technical papers in the AIAA archives describing twin fuselage motherships, frequently using a pair of siamese-twins 747s or even C-5s. Seems like adapting two existing airframes would be cheaper than a clean-sheet design.
All modern aircraft have four dimensions: span, length, height and politics.   TSR.2 got the first three right - Sir Sydney Camm

Offline bobbymike

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Re: Stratolaunch
« Reply #3 on: December 13, 2011, 08:57:15 pm »
Wow what a big booster it is carrying (relatively speaking for air launching), roughly 2.5X the weight/size of a Peacekeeper ICBM. Wonder what the payload to LEO is?
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AAAdrone

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Re: Stratolaunch
« Reply #4 on: December 13, 2011, 09:22:52 pm »
Wow what a big booster it is carrying (relatively speaking for air launching), roughly 2.5X the weight/size of a Peacekeeper ICBM. Wonder what the payload to LEO is?

The Stratolaunch video on the website states that the booster can deliver 13,500 lbs. to Low Earth Orbit.

Video link on facebook:
https://www.facebook.com/video/video.php?v=202596223158748

This is an interesting concept.  The launch vehicle is certainly quite massive and I can only imagine the sudden "bounce" the craft may experience upon jettisoning the booster.  However given the shear mass of the vehicle that may not be too much of an issue.  I would certainly like to see this project at least attempted.
« Last Edit: December 13, 2011, 09:26:37 pm by AAAdrone »

Offline Lauge

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Re: Stratolaunch
« Reply #5 on: December 13, 2011, 11:39:42 pm »
Wow what a big booster it is carrying.....

"Is that a big booster, or are you just happy to see me?"
 
Sorry - couldn' resist. Back to topic, promise  ;D
 
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Offline Mat Parry

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Re: Stratolaunch
« Reply #6 on: December 14, 2011, 12:49:20 am »
The Stratolaunch video on the website states that the booster can deliver 13,500 lbs. to Low Earth Orbit.

Could be useful for boosting an X37B  ;)  still, the hanger for this beast would be truly gigantic!

Offline Hobbes

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Re: Stratolaunch
« Reply #7 on: December 14, 2011, 04:42:37 am »
The booster looks like it has a Dragon capsule on top, which would put its diameter at 3.6 m (same as the Falcon 9). A few years ago, SpaceX had plans to create a 'Falcon 5', which this design looks similar to. It'd be fairly easy to adapt the Falcon 9 design (just delete 4 engines, change the first stage length), leaving the wing as the only new development.
« Last Edit: December 14, 2011, 07:52:28 am by Hobbes »

Offline George Allegrezza

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Re: Stratolaunch
« Reply #8 on: December 14, 2011, 05:49:48 am »
There are plenty of technical papers in the AIAA archives describing twin fuselage motherships, frequently using a pair of siamese-twins 747s or even C-5s. Seems like adapting two existing airframes would be cheaper than a clean-sheet design.


The nose of the piloted fuselage looks very much like a 747, but I don't know if it's an actual 747 forward section.  Someone on NSF (yeah I know) claims it's using 747 landing gear.  The engines are of course off-the-shelf, and I would assume the avionics are as well.

Offline Skyblazer

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Re: Stratolaunch
« Reply #9 on: December 14, 2011, 06:21:52 am »
There are plenty of technical papers in the AIAA archives describing twin fuselage motherships, frequently using a pair of siamese-twins 747s or even C-5s. Seems like adapting two existing airframes would be cheaper than a clean-sheet design.


The nose of the piloted fuselage looks very much like a 747, but I don't know if it's an actual 747 forward section.  Someone on NSF (yeah I know) claims it's using 747 landing gear.  The engines are of course off-the-shelf, and I would assume the avionics are as well.

According to the promotional videos, the engines will be standard 747 types. As for the fuselage, cross section clearly shows it to be much slimmer than that of the 747, so I guess it's only passing resemblance.

Offline AeroFranz

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Re: Stratolaunch
« Reply #10 on: December 14, 2011, 06:49:00 am »
Well, I'm sure Scaled is up to the task. Building a very large aircraft is not without its problems but it's been done before, unlike everything else they managed to do since 2004, which had no precedents. I worry more about the other components of the system and financial backing than Scaled's ability to pull this off.
All modern aircraft have four dimensions: span, length, height and politics.   TSR.2 got the first three right - Sir Sydney Camm

Offline Gridlock

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Re: Stratolaunch
« Reply #11 on: December 14, 2011, 08:08:54 am »
It looks like Damien Hirst and Howard Hughes got drunk together..


I wouldn't like to try landing one in a strong crosswind, that's for sure. Although it does have mass on its side. I wonder how long before the PLA buy a Mriya and a chainsaw? :)

Offline Hobbes

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Re: Stratolaunch
« Reply #12 on: December 14, 2011, 08:19:45 am »
There are plenty of technical papers in the AIAA archives describing twin fuselage motherships, frequently using a pair of siamese-twins 747s or even C-5s. Seems like adapting two existing airframes would be cheaper than a clean-sheet design.

Buying two 747s isn't going to be cheap. For the several hundred M$ they'll cost, you can do an awful lot of design and fabrication work. Your clean-sheet design will also have much lighter fuselages, so it'll have more payload.

Offline Skyblazer

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Re: Stratolaunch
« Reply #13 on: December 14, 2011, 08:27:16 am »
Your clean-sheet design will also have much lighter fuselages, so it'll have more payload.

Yes, composite materials will be part of the new aircraft's construction. None of it existed at the time the C-5 and 747 were developed and built.

Offline Hobbes

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Re: Stratolaunch
« Reply #14 on: December 14, 2011, 10:17:13 am »
Not only that; the fuselages can be designed for a payload of 0 kg; as far as I can see they only exist to provide a place for the undercarriage, crew and tailplanes. Not a floor that can carry 100 tons.

Offline blackstar

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Re: Stratolaunch
« Reply #15 on: December 14, 2011, 11:31:47 am »
Well, I'm sure Scaled is up to the task. Building a very large aircraft is not without its problems but it's been done before, unlike everything else they managed to do since 2004, which had no precedents. I worry more about the other components of the system and financial backing than Scaled's ability to pull this off.

What is the largest aircraft built by Scaled?

Offline Hobbes

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Re: Stratolaunch
« Reply #16 on: December 14, 2011, 11:46:51 am »
Probably White Knight 2
Quote
General characteristics

    Payload: 17,000 kg (37,000 lb)[24] to 50000 ft.; 200 kg satellite to LEO[25] (test)    Length: 24 m (79 ft)    Wingspan: 43 m (141 ft)    Height: ()    Powerplant: 4 × Pratt & Whitney Canada PW308 turbofanPerformance    Service ceiling: 21.3 km (70,000 ft [24])
(from Wikipedia)
« Last Edit: December 14, 2011, 12:39:58 pm by Hobbes »

Offline Byeman

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Re: Stratolaunch
« Reply #17 on: December 14, 2011, 11:48:11 am »
Not only that; the fuselages can be designed for a payload of 0 kg; as far as I can see they only exist to provide a place for the undercarriage, crew and tailplanes. Not a floor that can carry 100 tons.

No, they will be carrying LOX tanks for topping off the booster

Offline AeroFranz

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Re: Stratolaunch
« Reply #18 on: December 14, 2011, 12:51:41 pm »
Buying two 747s isn't going to be cheap. For the several hundred M$ they'll cost, you can do an awful lot of design and fabrication work. Your clean-sheet design will also have much lighter fuselages, so it'll have more payload.

All previous points made about superiority of clean sheet design duly noted and for the most part agreed on. I do not think however on the cost issue. Who says you have to buy new 747s? IIRC, the NASA B-52 mothership had the lowest flight hours of ANY B-52 in the air force, so airframe life is not an issue. As a matter of fact, a few years back I spent an evening at the Voyager diner at the Mojave airport a couple of doors down from Scaled. From there I could see dozens of airliners parked out in the desert for lack of use (9/11? economic downturn?), I can't remember if there were 747s...but you get my point, I am sure that there are 747s to be had, and I don't think you can build a new 1.2M pounds design for less than it takes to buy two used 747s that benefitted from ~50 years of high volume production.
The catch in using low wing aircraft lies in having to hang the payload underneath the wing, hence the better suitability of C-5s. Hell, not all the remaining air force C-5s are being converted to -Ms, maybe you can get a deal on a couple that are redundant. Too bad the old models are down half the time for maintenance.
All modern aircraft have four dimensions: span, length, height and politics.   TSR.2 got the first three right - Sir Sydney Camm

Offline mboeller

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Re: Stratolaunch
« Reply #19 on: December 15, 2011, 12:52:26 am »
IMHO,
using 2 747 fuselages would not work because of the cantilever-design with the wing below the fuselage.
Redesigning the fuselage with a wing above the fuselage would cost more than a clean-sheet design.

AAAdrone

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Re: Stratolaunch
« Reply #20 on: December 15, 2011, 10:00:24 am »
IMHO,
using 2 747 fuselages would not work because of the cantilever-design with the wing below the fuselage.
Redesigning the fuselage with a wing above the fuselage would cost more than a clean-sheet design.

I don't really think those are 747 fuselages.  Like Stargazer said the cross-section of each fuselage appears to be too small for them to be made by sticking two 747s together.  The fuselages might be designed from the ground up to look conveniently similar to a 747 though.  The engines and supposedly the landing gear and possibly even the avionics will also be taken from the 747.  Basically the general superstructure is clean-sheet but the more intricate and complex parts are off the shelf if my beliefs are correct.

Offline Gridlock

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Re: Stratolaunch
« Reply #21 on: December 15, 2011, 11:04:57 am »
If you're working largely in CFD then is there an economy available in utilising well-understood and -modelled airframe shapes? My guess.


In the modelling and therefore final shape I mean, not that it's made of 747.

Offline blackstar

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Re: Stratolaunch
« Reply #22 on: December 16, 2011, 07:03:05 am »
There's a good assessment here:

http://www.newspacejournal.com/2011/12/15/stratolaunch-a-contrarian-view/

I think this is the key point:

"Instead, I’ve been pondering this question: what problem does this system solve? That’s the key question for any business venture, not just a launch vehicle company. What can Stratolaunch do that others can’t do, or do as well or as cheaply? Air launch has its advantages, but also carries with it some disadvantages and other issues. That, coupled with what the company has released about its technical capabilities, leads me to wonder if the Stratolaunch system will really be that competitive over more conventional launch systems in service or under active development today."

However, look also at his discussion of the aircraft cost. This is going to be an expensive aircraft. Standard cost models indicate that it will cost billions.

And I think it is also worth asking if it is realistic for Scaled to build such a large aircraft. Scaled builds unique, one-of-a-kind, relatively small and low-powered/low-performance vehicles. This aircraft is of a size that only the major aerospace contractors have experience with.

I think this is a vanity project and it's going to fold in a few years. It certainly doesn't serve any part of the over-saturated launch market that requires these unique capabilities.

Offline RanulfC

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Re: Stratolaunch
« Reply #23 on: December 16, 2011, 08:21:38 am »
Ok, what's "known" so far:
 
- StratoLaunch has already purchased two (2) used 747s they will be stripping for landing gear and avionics. (They said yesterday they are looking to purchase a third for parts also)
 
- Fuselage and wings will be all "new" build, the main reason the cockpit area looks like that of a 747 is because they plan to use the layour and controls from a 747.
 
- Carrier Aircraft will be runway limited to at least 12,000ft runways, however it will NOT be a "dedicated" Air-Launch-Vehicle but will be capable of carrying out-sized and specialty cargo with a 9,200 mile range
 
- The rocket will be a "varient" of the Falcon-9 with 5 engines in the first stage, 1 engine in the second stage. @13,500lbs to LEO delivery
 
- The video (here:https://www.facebook.com/video/video.php?v=202596223158748) shows the whole flight profile.
 
- Both Space-X (booster) and Scaled (Carrier Aircraft) are on-board as "contractors" only. Allen is listed as an "investor" while Rutan is on the "board" as well as Mike Griffin (yes that one :) )
 
Pretty much everything else is speculation and a lot of it. According to the press conference Allen ONLY decided to release as much as he has because construction of the hanger in Mojave is supposed to start soon and that's something they would not be able to "hide" from competitiors.
 
Oh and for the general FYI I found this paper at NTRS which gives some pretty good information on the hows and whys of Air Launch To Orbit economics:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20070002822_2007001607.pdf
 
Randy

RGClark

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Re: Stratolaunch
« Reply #24 on: December 16, 2011, 09:27:30 am »
There's a good assessment here:

http://www.newspacejournal.com/2011/12/15/stratolaunch-a-contrarian-view/

I think this is the key point:

"Instead, I’ve been pondering this question: what problem does this system solve? That’s the key question for any business venture, not just a launch vehicle company. What can Stratolaunch do that others can’t do, or do as well or as cheaply? Air launch has its advantages, but also carries with it some disadvantages and other issues. That, coupled with what the company has released about its technical capabilities, leads me to wonder if the Stratolaunch system will really be that competitive over more conventional launch systems in service or under active development today."
However, look also at his discussion of the aircraft cost. This is going to be an expensive aircraft. Standard cost models indicate that it will cost billions.
...

 DARPA with its Alasa program wants this type of airlaunch system but for small payloads, ca. 100 pounds:

Article:
US Military Wants to Launch Satellites from Airplanes.
Date: 07 November 2011 Time: 12:08 PM ET
http://www.space.com/13529-darpa-military-airplane-satellite-launches.html

 Curiously, they also expect it to fly by 2015. For launches this small, it might work to use a WhiteKnight2 for the carrier aircraft, and a Falcon 1 first stage as the rocket, perhaps shrunk slightly to fit within the carrying capacity of the WhiteKnight2.
 DARPA is basing the feasibility of such air launch systems on this study:

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110015353_2011016245.pdf

 A focus of this study was on systems intermediate in size between DARPA's Alasa and Stratolaunch, with for example the carrier aircraft being 747-sized and the rocket being of Falcon 1e size.


    Bob Clark

RGClark

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Re: Stratolaunch
« Reply #25 on: December 16, 2011, 09:44:33 am »
...
Oh and for the general FYI I found this paper at NTRS which gives some pretty good information on the hows and whys of Air Launch To Orbit economics:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20070002822_2007001607.pdf
 
Randy

 The benefits of air launch go beyond just the speed and altitude attained. This is discussed in this report:

Air Launching Earth-to-Orbit Vehicles: Delta V gains from Launch Conditions and Vehicle Aerodynamics.
Nesrin Sarigul-Klijn University of California, Davis, CA, UNITED STATES; Chris Noel University of California, Davis, CA, UNITED STATES; Marti Sarigul-Klijn University of California, Davis, CA, UNITED STATES
AIAA-2004-872
42nd AIAA Aerospace Sciences Meeting and Exhibit, Reno, Nevada, Jan. 5-8, 2004
http://pdf.aiaa.org/preview/CDReadyMASM04_665/PV2004_872.pdf  [first page only]

 The conclusions are summarized in this online lecture:

A.4.2.1 Launch Method Analysis (Air Launch).
"For a launch from a carrier aircraft, the aircraft speed will directly reduce the Δv required to attain LEO. However, the majority of the Δv benefit from an air launch results
from the angle of attack of the vehicle during the release of the rocket. An
ideal angle is somewhere of the order of 25° to 30°.
"A study by Klijn et al. concluded that at an altitude of 15250m, a rocket launch with the
carrier vehicle having a zero launch velocity at an angle of attack of 0° to
the horizontal experienced a Δv benefit of approximately 600 m/s while a launch
at a velocity of 340m/s at the same altitude and angle of attack resulted in a
Δv benefit of approximately 900m/s. The zero launch velocity situations can
be used to represent the launch from a balloon as it has no horizontal velocity.
"Furthermore, by increasing the angle of attack of the carrier vehicle to
30° and launching at 340m/s, a Δv gain of approximately 1100m/s
was obtained. Increasing the launch velocity to 681m/s and 1021m/s produced a
Δv gain of 1600m/s and 2000m/s respectively.
"From this comparison, it can be seen that in terms of the Δv gain, an airlaunch is
superior to a ground launch. As the size of the vehicle decreases, this superiority
will have a larger effect due to the increased effective drag on the vehicle."
https://engineering.purdue.edu/AAE/Academics/Courses/aae450/2008/spring/report_archive/reportuploads/appendix/propulsion/A.4.2.1%20Launch%20Method%20Analysis%20(Air%20Launch).doc

 A speed of 340 m/s is a little more than Mach 1, while subsonic transport aircraft typically cruise
slightly below Mach 1. So the delta-V saving could still be in the range of 1,000 m/s with air launch,
a significant savings by the rocket equation.


    Bob Clark

Offline blackstar

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Re: Stratolaunch
« Reply #26 on: December 16, 2011, 09:55:05 am »
DARPA is basing the feasibility of such air launch systems on this study:

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110015353_2011016245.pdf


This is the interim report. The final report has been completed and should be available somewhere.

Offline ouroboros

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Re: Stratolaunch
« Reply #27 on: December 17, 2011, 12:36:13 am »
Smart to make the carrier aircraft capable of carrying outsize cargo (via a cargo pod?) as a revenue generator when not busy throwing rockets, much like the AN-225. There is also the potential market for sale/lease to other air launchable systems (XCOR Lynx? Possible B-52 replacement for NASA for air drop experiments? DARPA and friends?) but the big takeaway is the listed range of 1300nm. This underlies a possible launch approach of going uprange, launching, and recovering the first stage of the rocket via a "glide forward" methodology rather than the traditional "boost back" profile, allowing recovery of all assets at the same airport/spaceport and not taking a large deltaV hit on the rocket for the recovery boost.

The rocket concept is shown with a Pegasus style wing (is this truly necessary for the trajectory?), but nothing is stopping SpaceX from adapting their Hopper VTVL related technologies they are developing for the recoverable Falcon 9 first stage to do a vertical propulsive landing for stage recovery.

Offline Skyblazer

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Re: Stratolaunch
« Reply #28 on: December 17, 2011, 02:07:32 am »
I don't deem it irrational to build a carrier aircraft that can carry just about any kind of self-propelled vehicle to high altitudes. Programs like Pegasus, X-37, X-38, X-40, X-43, X-51, SpaceShipOne, SpaceShipTwo, XCOR Lynx, and many others have relied or will rely on this capability. I wouldn't be surprised if the operating and maintenance costs of a Stratolauncher were distinctly smaller than those of a Stratofortress. Having one platform that can fit the bill with less costs and operate from US ground, especially now that NASA itself is using foreign launch sites for its own programs, seems pretty seems sensible to me.

Offline Byeman

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Re: Stratolaunch
« Reply #29 on: December 17, 2011, 05:29:21 am »
This underlies a possible launch approach of going uprange, launching, and recovering the first stage of the rocket via a "glide forward" methodology rather than the traditional "boost back" profile, allowing recovery of all assets at the same airport/spaceport and not taking a large deltaV hit on the rocket for the recovery boost.


Huh?  Yeah, right.  How many airports do you think can support this aircraft?  There are just couple that can be used to "launch" the configuration. 

Offline Skyblazer

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Re: Stratolaunch
« Reply #30 on: December 17, 2011, 05:40:24 am »
This underlies a possible launch approach of going uprange, launching, and recovering the first stage of the rocket via a "glide forward" methodology rather than the traditional "boost back" profile, allowing recovery of all assets at the same airport/spaceport and not taking a large deltaV hit on the rocket for the recovery boost.


Huh?  Yeah, right.  How many airports do you think can support this aircraft?  There are just couple that can be used to "launch" the configuration.

Also remember that Mojave is now tagged as a spaceport since the SpaceShip venture was started. I am sure that they will make sure the Stratolauncher can take off from and land there.

Offline Nik

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Re: Stratolaunch
« Reply #31 on: December 17, 2011, 11:21:59 am »
One outré thought: If those twin hulls carry LOX to top-off the rocket's cryo-tank, there's a slim chance that the aircraft could be fitted with 'jato' nozzles burning kerosene / LOX, reducing the runway requirements at the expense of some range...


Uh, would water-injection, per Harriers' Pegasus engine help ?

Offline blackstar

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Re: Stratolaunch
« Reply #32 on: December 18, 2011, 02:56:30 pm »
This underlies a possible launch approach of going uprange, launching, and recovering the first stage of the rocket via a "glide forward" methodology rather than the traditional "boost back" profile, allowing recovery of all assets at the same airport/spaceport and not taking a large deltaV hit on the rocket for the recovery boost.


Huh?  Yeah, right.  How many airports do you think can support this aircraft?  There are just couple that can be used to "launch" the configuration.

Stop being so pessimistic. This can easily be made to work if you simply add a few more completely unproven technologies to the mix as well. If you use a VASIMR engine, powered by a Helium-3 fusion reactor, with guidance provided by space based solar power, it all becomes possible.

Offline RanulfC

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Re: Stratolaunch
« Reply #33 on: December 19, 2011, 07:34:05 am »
Following list has @ 30 runways in the US that meet or exceed the 12,000ft runway requirement of the carrier aircraft:
http://en.wikipedia.org/wiki/List_of_longest_runways
 
Randy

Offline George Allegrezza

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Re: Stratolaunch
« Reply #34 on: December 19, 2011, 09:03:44 am »
Stop being so pessimistic. This can easily be made to work if you simply add a few more completely unproven technologies to the mix as well. If you use a VASIMR engine, powered by a Helium-3 fusion reactor, with guidance provided by space based solar power, it all becomes possible.


You forgot the propellant depots at L1.

Offline blackstar

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Re: Stratolaunch
« Reply #35 on: December 19, 2011, 08:04:09 pm »
Stop being so pessimistic. This can easily be made to work if you simply add a few more completely unproven technologies to the mix as well. If you use a VASIMR engine, powered by a Helium-3 fusion reactor, with guidance provided by space based solar power, it all becomes possible.


You forgot the propellant depots at L1.

No, I didn't. I figured that with the inclusion of the unicorn, they weren't necessary.

Offline Grey Havoc

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Re: Stratolaunch
« Reply #36 on: January 22, 2012, 07:54:04 am »
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Re: Stratolaunch
« Reply #37 on: January 22, 2012, 02:46:51 pm »
Stratolaunch Systems Announces Ground Breaking At Mojave (Spacedaily.com)

Thanks! I really hope they can get this project to its completion, it is exciting when something that new and that big is undertaken!

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Re: Stratolaunch
« Reply #38 on: April 17, 2012, 12:37:30 pm »
According to the latest issue of Popular Mechanics, the Stratolaunch aircraft is known at Scaled as the Model 351 and named the Roc.

   

http://www.popularmechanics.com/technology/aviation/news/say-hello-to-stratolaunch-the-worlds-largest-plane-6705761?click=pp

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Re: Stratolaunch
« Reply #39 on: April 17, 2012, 07:53:50 pm »
At their last press conference they indicated that the aircraft would look different than the early concept art. I wonder if this reflects a more accurate version?

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Re: Stratolaunch
« Reply #40 on: July 14, 2012, 06:28:29 pm »
Some information indicating that Scaled was considering using 747s for the Stratolaunch effort seems to be confirmed. A look at the civil register shows that Scaled Composites acquired two Boeing 747-422  (former United Airlines) aircraft: N196UA on March 8, and N198UA on April 14. Both aircraft were built in 1997.

http://www.aircraftone.com/search.asp?pg=2&type=rn&criteria=Scaled+Composites&gid=82DE1B9D-9B4A-46DF-98F0-F223BCBF2696&rc=13&prevpage=1

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Re: Stratolaunch
« Reply #41 on: July 15, 2012, 05:03:09 am »
Some information indicating that Scaled was considering using 747s for the Stratolaunch effort seems to be confirmed.

That didn't confirm it.  The many pictures of 747's at the Stratolaunch facility at Mojave did months ago as did their news release.

http://hobbyspace.com/nucleus/index.php?itemid=35339
http://www.stratolaunch.com/news.html
« Last Edit: July 15, 2012, 05:07:04 am by Byeman »

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Re: Stratolaunch
« Reply #42 on: July 15, 2012, 11:24:41 am »
That didn't confirm it.

Fair enough. They could be just snatching engines and stuff OR they could decide to use the fuselages too. It's too early to tell, but I'm tempted to believe that from a financial point of view, a proof-of-concept vehicle would be much less costly to do by joining two proven existing fuselages instead of building two unproven ones from scratch.

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Re: Stratolaunch
« Reply #43 on: July 15, 2012, 12:10:07 pm »
The 747 fuselage is built for a low wing, which would make it difficult to fit the rocket underneath. They need a high wing.

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Re: Stratolaunch
« Reply #44 on: July 15, 2012, 01:42:10 pm »
In principle they could connect 2 747 fuselages with a straight wing segment and carry the rocket on *top*. Separation would be a bit terrifying, but it'd be possible. Also, they could have a "gull wing" center section that bows upwards. Heavy and complex, but doable.
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Re: Stratolaunch
« Reply #45 on: July 15, 2012, 02:52:13 pm »
Also, they could have a "gull wing" center section that bows upwards. Heavy and complex, but doable.

Yeah, that was indeed a solution studied by Myasishchev on their 3M2 and AKC projects. But the wing was high-rooted already.

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Re: Stratolaunch
« Reply #46 on: November 27, 2012, 07:19:34 pm »
In God we trust, all others we monitor. :-p

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Re: Stratolaunch
« Reply #47 on: November 29, 2012, 02:05:31 pm »
We'll have to see what happens next. On the one hand, you can always find another contractor if you pay them enough. But on the other hand, I suspect that building an air-launched rocket that big is going to be a really tough challenge. Imagine all the propellant sloshing issues. And I have always suspected that they would have a hard time getting an airworthiness certificate for the aircraft because of what is likely to happen if they lose an engine during the takeoff roll with a fully loaded aircraft and rocket--it just careens down the runway and creates a very big explosion.

The aircraft would be cool, but I've never expected this thing to go anywhere.

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Re: Stratolaunch
« Reply #48 on: November 29, 2012, 04:41:05 pm »
... And I have always suspected that they would have a hard time getting an airworthiness certificate for the aircraft because of what is likely to happen...

The cool thing about flying strange aircraft in the US is that they won't need a full airworthiness certificate.  They can get an experimental flight permit with some restrictions - like making sure you only kill company employees when it blows up after an engine failure.
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Re: Stratolaunch
« Reply #49 on: November 29, 2012, 07:42:26 pm »
... And I have always suspected that they would have a hard time getting an airworthiness certificate for the aircraft because of what is likely to happen...

The cool thing about flying strange aircraft in the US is that they won't need a full airworthiness certificate.  They can get an experimental flight permit with some restrictions - like making sure you only kill company employees when it blows up after an engine failure.

But how likely is the FAA going to simply give them a pass for carrying around thousands of pounds of rocket fuel?

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Re: Stratolaunch
« Reply #50 on: November 30, 2012, 12:57:01 am »
We'll have to see what happens next. On the one hand, you can always find another contractor if you pay them enough. But on the other hand, I suspect that building an air-launched rocket that big is going to be a really tough challenge.

If you read the article, it says they're talking to Orbital Sciences, which has been using the Pegasus winged air-launched rocket for years now. And propellant sloshing issues are familiar territory for anyone who's built a rocket engine that needs to be started in 0 G.

Sure, it's a challenge, but it seems to me they're talking to the right people.

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Re: Stratolaunch
« Reply #51 on: November 30, 2012, 05:32:25 am »
We'll have to see what happens next. On the one hand, you can always find another contractor if you pay them enough. But on the other hand, I suspect that building an air-launched rocket that big is going to be a really tough challenge.

If you read the article, it says they're talking to Orbital Sciences, which has been using the Pegasus winged air-launched rocket for years now. And propellant sloshing issues are familiar territory for anyone who's built a rocket engine that needs to be started in 0 G.

Sure, it's a challenge, but it seems to me they're talking to the right people.

Covered by the second sentence I wrote above--anybody will work, even on something stupid, if you offer them enough money.

As for propellant sloshing, note that Pegasus doesn't have to deal with this. And there's a big difference between zero g and what a very large rocket dropped from a very large aircraft would experience. Indeed, it might experience negative gees (i.e. with the fuel flowing away from the engine).

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Re: Stratolaunch
« Reply #52 on: November 30, 2012, 09:35:19 am »

But how likely is the FAA going to simply give them a pass for carrying around thousands of pounds of rocket fuel?

This is truly the least of their problems.  The FAA, by explicit mandate, could care less if you blow yourself up.  They just want to make sure you don't blow anybody else up.  This is easily done by testing over unpopulated regions in the American SW.  Like just east of Mojave, Palmdale and Edwards for instance.  And that is why you find such interesting activities being carried out at Mojave, Palmdale and Edwards.
« Last Edit: November 30, 2012, 06:53:08 pm by Bill Walker »
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Re: Stratolaunch
« Reply #53 on: November 30, 2012, 04:32:40 pm »
Some more:

http://www.spacenews.com/article/orbital-science-replaces-spacex-on-stratolaunch-project#.ULkvf4UXFFR

"“We agreed with SpaceX that to meet our design requirements, the existing Falcon 9 architecture would require significant structural modifications to incorporate a fin/chine and to be carried horizontally,” Wentz said. “As we studied the design, it became apparent that SpaceX would have to make significant modifications to their manufacturing process to accommodate our configuration, which would have a pronounced effect on their business model.”"

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Re: Stratolaunch
« Reply #55 on: March 24, 2013, 06:02:24 am »
Yeah, I always expected that, and I think they said that the early artwork was provisional and that they were NOT going to use the 747 fuselages. Makes sense. The 747 fuselage had much more internal volume than they require, so they could save a lot of mass with a new one (or two).

My view is that I that the airplane will probably fly but the rocket probably won't. And it's hard to see how this is going to be any cheaper than SpaceX. I think this is a rich guy's vanity project. But it's still cool.

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Re: Stratolaunch
« Reply #56 on: August 16, 2013, 04:38:57 pm »
Here are larger versions of two early pictures (displaying the initial design) that appeared in the first pages of this thread. They were illustrated by Vladimir Shelest for Popular Mechanics:




Larger-size versions of these paintings (and more of Shelest's great works) can be seen here: http://shelest.deviantart.com/gallery/

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Re: Stratolaunch
« Reply #57 on: August 16, 2013, 05:46:03 pm »
Nice.  B)    I really hope Scaled is successful enough with their White Knight 2 / SpaceShip 2 to fund this bigger aircraft.
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Re: Stratolaunch
« Reply #58 on: August 17, 2013, 05:31:14 pm »
Nice.  B)    I really hope Scaled is successful enough with their White Knight 2 / SpaceShip 2 to fund this bigger aircraft.


Huh?  Stratolaunch, the company, is funding this aircraft

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Re: Stratolaunch
« Reply #59 on: August 17, 2013, 06:03:22 pm »
Stratolaunch, the company, is funding this aircraft

Absolutely. Scaled Composites designs and will build it, but it's a Stratolaunch product. There have actually been very few Scaled projects that were actually company funded. Most of the time the work is done on behalf of another, often bigger corporate entity.

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Re: Stratolaunch
« Reply #60 on: August 17, 2013, 06:34:42 pm »
Okay, let me rephrase that.  I hope the White Knight 2 / Spaceship 2 is successful enough that its success encourages investment in Stratolaunch.
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Re: Stratolaunch
« Reply #61 on: August 18, 2013, 05:43:43 am »
Okay, let me rephrase that.  I hope the White Knight 2 / Spaceship 2 is successful enough that its success encourages investment in Stratolaunch.

Why?  They are competitors.

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Re: Stratolaunch
« Reply #62 on: August 18, 2013, 05:55:56 am »
Okay, let me rephrase that.  I hope the White Knight 2 / Spaceship 2 is successful enough that its success encourages investment in Stratolaunch.

Why?  They are competitors.

They're not competitors. Virgin Galactic is suborbital. They have said that eventually they want to get into the orbital business, but even then that will be for very small payloads. Stratolaunch is much bigger. They operate in entirely different parts of the market.

But I don't think the success of one will affect the other. They share a similar launch method, but that's it. It's like comparing a Cessna to a 787. They do different things and have different requirements.

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Re: Stratolaunch
« Reply #63 on: October 07, 2013, 09:00:59 am »
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Re: Stratolaunch
« Reply #64 on: October 07, 2013, 09:57:39 am »
http://www.aviationweek.com/Blogs.aspx?plckBlogId=Blog:04ce340e-4b63-4d23-9695-d49ab661f385&plckPostId=Blog%3a04ce340e-4b63-4d23-9695-d49ab661f385Post%3add366625-ca5e-4215-8af1-5f83237def46
 
Rocket looks to be a different configuration than in earlier pictures in this thread.

I have my doubts. They displayed this at the Space Foundation conference in April. I was there. I took pictures of it (which I cannot find--where did I put them?). I think that the photos on this site were also taken at the same conference. So I don't think anything has changed. But maybe I'm wrong and should look for my images again.

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Re: Stratolaunch
« Reply #65 on: October 07, 2013, 10:00:32 am »
http://www.aviationweek.com/Blogs.aspx?plckBlogId=Blog:04ce340e-4b63-4d23-9695-d49ab661f385&plckPostId=Blog%3a04ce340e-4b63-4d23-9695-d49ab661f385Post%3add366625-ca5e-4215-8af1-5f83237def46
 
Rocket looks to be a different configuration than in earlier pictures in this thread.

I have my doubts. They displayed this at the Space Foundation conference in April. I was there. I took pictures of it (which I cannot find--where did I put them?). I think that the photos on this site were also taken at the same conference. So I don't think anything has changed. But maybe I'm wrong and should look for my images again.

To me the back end looks like two segments of ATK's ASRM with single nozzle?
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Re: Stratolaunch
« Reply #66 on: October 07, 2013, 05:26:19 pm »
That's what I was thinking!
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Re: Stratolaunch
« Reply #67 on: October 08, 2013, 05:44:34 am »

To me the back end looks like two segments of ATK's ASRM with single nozzle?

Too heavy for this application and the casings are owned by NASA, which is planning on using them in an expendable mode for early versions of SLS.

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Re: Stratolaunch
« Reply #68 on: May 24, 2014, 07:20:59 am »
Aerojet Rocketdyne to Provide Upper-Stage Propulsion for Revolutionary Eagles Launch System

SACRAMENTO, Calif., May 19, 2014 (GLOBE NEWSWIRE) -- Aerojet Rocketdyne, a GenCorp (NYSE:GY) company, has received a contract from Stratolaunch Systems Corporation (SSC) to provide six RL10C-1 production engines, with an option to provide an additional six RL10C-1 production engines at a later date, for the third stage of a revolutionary commercial air-launch system. The inaugural launch of Thunderbolt, the air-launch vehicle designed and developed for SSC, is scheduled for 2018.

"Aerojet Rocketdyne is pleased to provide RL10C-1 production engines for the Stratolaunch air-launch vehicle," said Steve Bouley, vice president of Space Launch Systems at Aerojet Rocketdyne. "The RL10 family of engines has a long history of reliability and dependability. This contract expands our reach into commercial ventures and builds greater volume, providing more affordable propulsion to all of our customers."

The design concept for The Eagles Launch System involves the launch of an unmanned rocket dubbed Thunderbolt, carrying a commercial or government payload from beneath the fuselage of a giant carrier aircraft. According to the concept, the carrier aircraft will be powered by six Boeing 747 class jet engines and have a wingspan greater than the length of a football field. Upon reaching a prescribed altitude, the rocket will be dropped from the aircraft, at which point two stages of solid rocket boosters will fire and propel the rocket skyward. Once the solid rocket boosters are expended, two Aerojet Rocketdyne RL10C-1 engines will ignite to ultimately place the satellite into proper orbit.

The RL10C-1 is a liquid-fuel cryogenic rocket engine designed and developed from the RL10 family of upper-stage engines, which have accumulated one of the most impressive lists of accomplishments in the history of space propulsion. The RL10 has helped place numerous military, government and commercial satellites into orbit over the last five decades, and powered scientific space-probe missions to nearly every planet in our solar system. This new application for the RL10 family opens a new era within a commercial venture that will again be a platform for demonstrated reliability and mission success.

Aerojet Rocketdyne is a world-recognized aerospace and defense leader providing propulsion and energetics to the space, missile defense and strategic systems, tactical systems and armaments areas, in support of domestic and international markets. GenCorp is a diversified company that provides innovative solutions that create value for its customers in the aerospace and defense, and real estate markets. Additional information about Aerojet Rocketdyne and GenCorp can be obtained by visiting the companies' websites at www.Rocket.com and www.GenCorp.com.
   
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Re: Stratolaunch
« Reply #69 on: May 24, 2014, 07:44:44 am »
I am genuinely excited by this program.  It's private (no government meddling) and they have deep pockets.
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Re: Stratolaunch
« Reply #71 on: February 10, 2015, 08:51:11 pm »
Carrier aircraft under construction.

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Re: Stratolaunch
« Reply #72 on: February 11, 2015, 02:27:53 am »
Even if Stratolaunch fails at the rocket launch hurdle, the Roc will stuck as a pretty impressive aircraft. If the rocket launch business never materialize at all, I cann that thing being used as a one shot competitor to the An-225 for oversized cargo...
Do they plan to build a second aircraft ?
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Re: Stratolaunch
« Reply #73 on: February 11, 2015, 03:10:18 am »
I'd think the number of airfields it could operate out of would be relatively limited given its landing gear track.
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Re: Stratolaunch Systems Roc
« Reply #75 on: February 26, 2015, 10:47:19 am »
Uploaded on Dec 13, 2011

Stratolaunch Systems is pioneering innovative solutions to revolutionize space transportation. Watch the video or visit http://www.stratolaunch.com to learn more.


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Re: Stratolaunch
« Reply #76 on: February 27, 2015, 08:19:42 pm »
That video dates from 2011. They have changed some things since then. There's also some recent video of the aircraft under construction.

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Re: Stratolaunch
« Reply #77 on: March 01, 2015, 03:38:24 am »
From june 2013
the spaceX Falcon rocket is replace by Pegasus like solid rocket with third stage with liquid fuel engine.
and it have to carry the Dream Chaser into orbit

« Last Edit: June 01, 2015, 08:26:36 pm by Michel Van »
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Re: Stratolaunch
« Reply #78 on: March 01, 2015, 10:52:36 am »
According to the latest information from Stratolaunch, the Orbital Sciences-built Thunderbolt will be 131-ft long, and weigh around 550,000 lb

The three-stage vehicle will use ATK-provided solid rocket motors for the first and second stages, while the third will be powered by two liquid-fueled Aerojet Rocketdyne RL10C engines
-------------------------------------------------------------------
I searched Thunderbolt and couldn't find anything specific on the solid rocket motors - thrust, diameter, etc. - has anyone else come across anything?
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Re: Stratolaunch
« Reply #79 on: March 01, 2015, 11:20:42 am »
In a way, I'm a little surprised they went with solid propellent.  I know, it's MUCH less complicated than liquid fuel but the weight penalty. . .
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Re: Stratolaunch
« Reply #80 on: March 01, 2015, 01:19:40 pm »
In a way, I'm a little surprised they went with solid propellent.  I know, it's MUCH less complicated than liquid fuel but the weight penalty. . .

It makes a great deal of sense to go with a solid rocket.

For starters, solids are easier to deal with operationally than liquids. A setup like this is going to be complex enough; liquids hold the potential for destroying the whole vehicle with a simple leak. Plus solids are easier to develop (usually). Thus a solid gets you up sooner, easier.

As you point out, solids are heavier. In this case, that's a *bonus.* In aerospace almost nothing comes in on weight and with the promised performance. So if they get close with the solids, then they have  a lot of margin.

So... if they make a go of it with a solid, then:
1) They already have flight experience, which makes going to a liquid upper stage easier
2) Since they're used to hauling around a needlessly massive booster than can *just* put up a useful payload... a new liquid booster not only becomes an easier prospect, the potential for greatly improved payload performance exists.
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Re: Stratolaunch
« Reply #81 on: March 02, 2015, 08:37:36 am »

As you point out, solids are heavier. In this case, that's a *bonus.* In aerospace almost nothing comes in on weight and with the promised performance. So if they get close with the solids, then they have  a lot of margin.

 :o
Explain to me how a heavy booster that ends up being heavier than designed could increase their weight margin?

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Re: Stratolaunch
« Reply #82 on: March 02, 2015, 08:42:02 am »

As you point out, solids are heavier. In this case, that's a *bonus.* In aerospace almost nothing comes in on weight and with the promised performance. So if they get close with the solids, then they have  a lot of margin.

 :o
Explain to me how a heavy booster that ends up being heavier than designed could increase their weight margin?

That's not what he said.
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Re: Stratolaunch
« Reply #83 on: March 02, 2015, 12:01:05 pm »
How else could I parse "In aerospace almost nothing comes in on weight and with the promised performance"?

That's why I'm asking for clarification.

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Re: Stratolaunch
« Reply #84 on: March 02, 2015, 12:13:01 pm »
How else could I parse "In aerospace almost nothing comes in on weight and with the promised performance"?

That's why I'm asking for clarification.

He's saying if they come in okay with solid motors that leaves weight margin for if they decide they want to go with liquids down the road.
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Offline Orionblamblam

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Re: Stratolaunch
« Reply #85 on: March 02, 2015, 04:48:00 pm »

He's saying if they come in okay with solid motors that leaves weight margin for if they decide they want to go with liquids down the road.

Indeed so.

Look... if you're a modern aerospace engineer, trained up in the ways of razor-thin margins and overpromising, and your customer comes to you and says "I want a payload of 13,000 kg," you design for 13,000 kg. If you do your best and you come up short... you're in trouble. If you design to use a heavier system like solids and you come up short, you might be able to save your bacon by going to liquids. If you design for solids and actually squeak by, then by going to liquids you have an automatic performance improvement.

In other words: if you design for solids, you can always improve your performance by going to liquids. If you design for liquids, you have *already* designed for the best that can be done. If you come up short, there's not a whole lot you can do.
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Offline flanker

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Re: Stratolaunch
« Reply #86 on: June 01, 2015, 08:34:10 am »
And then there was none...

Quote
Its strategy has already undergone several changes, and right now what will be strapped under that huge wing is not clear. Originally, SpaceX was to provide the booster rocket; Vulcan then switched to relying on rocket-maker Orbital ATK.
As recently as last fall, Beames spoke about a plan to put a human-crewed spacecraft developed by Sierra Nevada on the tip of the Orbital booster rocket.
But now that human spaceflight plan is shelved, along with Orbital’s planned rocket.
Beames said Orbital’s rocket “was not hitting the economic sweet spot to generate revenue,” so Vulcan has reopened the design plan and is “evaluating over 70 different launch vehicle variants.”
This shift won’t affect the timetable for flying the carrier plane, he said, but it could mean “maybe a little delay” in the plans to use it to launch spacecraft into orbit.
Source; http://www.seattletimes.com/business/boeing-aerospace/space-wa2/

First SpaceX pulled out, now Orbital-ATK.
Push the envelope,watch it bend.

Offline RanulfC

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Re: Stratolaunch
« Reply #87 on: June 01, 2015, 04:05:41 pm »
And then there was none...

Quote
Its strategy has already undergone several changes, and right now what will be strapped under that huge wing is not clear. Originally, SpaceX was to provide the booster rocket; Vulcan then switched to relying on rocket-maker Orbital ATK.
As recently as last fall, Beames spoke about a plan to put a human-crewed spacecraft developed by Sierra Nevada on the tip of the Orbital booster rocket.
But now that human spaceflight plan is shelved, along with Orbital’s planned rocket.
Beames said Orbital’s rocket “was not hitting the economic sweet spot to generate revenue,” so Vulcan has reopened the design plan and is “evaluating over 70 different launch vehicle variants.”
This shift won’t affect the timetable for flying the carrier plane, he said, but it could mean “maybe a little delay” in the plans to use it to launch spacecraft into orbit.
Source; http://www.seattletimes.com/business/boeing-aerospace/space-wa2/

First SpaceX pulled out, now Orbital-ATK.


I read it as SL decided to not pursue the Orbital all-solid LV which make sense since it would neither be inexpensive nor very capable of reaching the targeted payload-to-orbit.


Key statement I thought was:
"The premise for all three companies is that launch vehicles must be reusable so getting to space becomes dramatically cheaper"


Which right there leaves out Orbital's design as none of it was reusable. The fact they are going back over 70 designs (which I seem to recall is more than they initially looked into) will hopefully lead to a more development and operationally capable vehicle. The LV was always going to be the long-pole in the development and operations of the concept. I just hope this will be open enough to get away from the idea of a self-lifting booster being a requirement. Probably not I suspect but there are a LOT of better ways to do it than has been suggested by the presentations so far.


Randy

Offline Orionblamblam

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Re: Stratolaunch
« Reply #88 on: July 09, 2015, 12:32:27 pm »
My stab at a 3-view of the Stratolaunch system. From US Launch Vehicle Projects #2.
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Re: Stratolaunch
« Reply #89 on: June 20, 2016, 10:43:52 am »
Quote
We are developing and fostering lots of different partnerships,” said Chuck Beames, president of Vulcan Aerospace and executive director of Stratolaunch Systems. “I would say that no company is ruled out right now.

Translation; we are completely alone. Plz, send help.

http://spacenews.com/stratolaunch-seeks-launch-partners-as-aircraft-nears-completion/
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Re: Stratolaunch
« Reply #90 on: June 20, 2016, 11:18:16 am »
My stab at a 3-view of the Stratolaunch system. From US Launch Vehicle Projects #2.

Very nice work, Orionblamblam! Thanks for sharing.

Offline blackstar

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Re: Stratolaunch
« Reply #91 on: June 20, 2016, 11:34:35 am »
Quote
We are developing and fostering lots of different partnerships,” said Chuck Beames, president of Vulcan Aerospace and executive director of Stratolaunch Systems. “I would say that no company is ruled out right now.

Translation; we are completely alone. Plz, send help.


They have a horrible chicken and egg situation: they have neither chicken nor egg. How do you get customers when you don't have a rocket? And how do you fund a rocket if you don't have customers?



Offline sferrin

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Re: Stratolaunch
« Reply #93 on: June 20, 2016, 01:03:22 pm »
Darn.  :'(  If they ever fly it maybe it will help things but how long does it sit idle waiting for a custom rocket to be built? 
« Last Edit: June 20, 2016, 01:06:35 pm by sferrin »
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Offline blackstar

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Re: Stratolaunch
« Reply #94 on: June 20, 2016, 04:23:36 pm »
.

Offline Archibald

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Re: Stratolaunch
« Reply #95 on: June 27, 2016, 11:52:03 pm »
very nice. So that is left of the 747 cockpit ? Damn, they really butchered it. Gone is the 747 hump !
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Offline flateric

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Re: Stratolaunch
« Reply #96 on: June 28, 2016, 02:37:37 am »
...
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Re: Stratolaunch
« Reply #97 on: June 28, 2016, 11:14:41 am »
very nice. So that is left of the 747 cockpit ? Damn, they really butchered it. Gone is the 747 hump !

The fuselage is all new. They're using the engines, landing gear and some avionics from the 747s.


Offline sferrin

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Re: Stratolaunch
« Reply #98 on: October 10, 2016, 01:23:43 pm »
http://www.spacedaily.com/reports/Orbital_ATK_and_Stratolaunch_Systems_Partner_to_Offer_Competitive_Space_Launch_Opportunities_999.html


Yo Dog. . .


Whoops.  I'd mistakenly taken that to be a Spaceship 1, and it's launcher.  Apparently it's an even less likely payload of THREE Pegasus XLs.  Unless they have nukes on the front end I don't know why you'd be launching three of them at a time.  (And if they were weapons you'd need a whole lot more than 1 airplane.)
« Last Edit: October 10, 2016, 01:27:43 pm by sferrin »
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Offline bobbymike

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Re: Stratolaunch
« Reply #99 on: October 10, 2016, 01:44:27 pm »
http://www.spacedaily.com/reports/Orbital_ATK_and_Stratolaunch_Systems_Partner_to_Offer_Competitive_Space_Launch_Opportunities_999.html


Yo Dog. . .


Whoops.  I'd mistakenly taken that to be a Spaceship 1, and it's launcher.  Apparently it's an even less likely payload of THREE Pegasus XLs.  Unless they have nukes on the front end I don't know why you'd be launching three of them at a time.  (And if they were weapons you'd need a whole lot more than 1 airplane.)
You had me at nukes.............  ;D
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Offline Archibald

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Re: Stratolaunch
« Reply #100 on: October 11, 2016, 04:16:17 am »
As I said in another forum - Roc can carry 250 tons while a Pegasus is 24 tons, so do the math - they could carry and launch ten of them ! (this is tongue-in-cheek. Roc is ridiculously oversized and overexpensive for Pegasus.
My gut feeling about this ?
"Folks, the Roc, world most largest airplane, is nearly finished and will fly soon. But we 'll have no rocket in time, which is annoying since that bird was especially build to air launch a big rocket. What rockets are currently air launched we could use off the shelf ? only one, what, the Pegasus ? Right, so let's take the Pegasus and hang it below the Roc... "
« Last Edit: October 11, 2016, 04:18:35 am by Archibald »
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Offline blackstar

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Re: Stratolaunch
« Reply #101 on: October 11, 2016, 06:22:46 pm »
"Folks, the Roc, world most largest airplane, is nearly finished and will fly soon. But we 'll have no rocket in time, which is annoying since that bird was especially build to air launch a big rocket. What rockets are currently air launched we could use off the shelf ? only one, what, the Pegasus ? Right, so let's take the Pegasus and hang it below the Roc... "

This is a face-saving press announcement, as you note.

The Pegasus has launched about 42 times in 26 years. which works out to about one launch every year and a half (or two launches every three years). There clearly are not that many payloads demanding the Pegasus.

The guy who designed the Pegasus has posted a lot to the NSF group and explained why they built it and what they expected it to do, and also how far they were off in their expectations. He's been quite honest about it. They expected a huge smallsat market that never emerged.

Offline sferrin

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Re: Stratolaunch
« Reply #102 on: October 11, 2016, 06:38:58 pm »
"Folks, the Roc, world most largest airplane, is nearly finished and will fly soon. But we 'll have no rocket in time, which is annoying since that bird was especially build to air launch a big rocket. What rockets are currently air launched we could use off the shelf ? only one, what, the Pegasus ? Right, so let's take the Pegasus and hang it below the Roc... "

This is a face-saving press announcement, as you note.

The Pegasus has launched about 42 times in 26 years. which works out to about one launch every year and a half (or two launches every three years). There clearly are not that many payloads demanding the Pegasus.

The guy who designed the Pegasus has posted a lot to the NSF group and explained why they built it and what they expected it to do, and also how far they were off in their expectations. He's been quite honest about it. They expected a huge smallsat market that never emerged.

Has he ever mentioned why it's never been proposed as a missile for the USAF?  Seems like it would be a slam dunk.
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Offline marauder2048

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Re: Stratolaunch
« Reply #103 on: October 11, 2016, 07:16:38 pm »

The guy who designed the Pegasus has posted a lot to the NSF group and explained why they built it and what they expected it to do, and also how far they were off in their expectations. He's been quite honest about it. They expected a huge smallsat market that never emerged.

So is there a sweetspot for (US domestic) smallsat launchers? SpaceX didn't deem $9 - $11 million for 1000 - 2000 lbs to be viable.

My understanding is that for Pegasus the cost of operating the host vehicle, Stargazer, turned out to be much greater than anticipated.

Offline blackstar

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Re: Stratolaunch
« Reply #104 on: October 13, 2016, 03:46:46 pm »

The guy who designed the Pegasus has posted a lot to the NSF group and explained why they built it and what they expected it to do, and also how far they were off in their expectations. He's been quite honest about it. They expected a huge smallsat market that never emerged.

So is there a sweetspot for (US domestic) smallsat launchers? SpaceX didn't deem $9 - $11 million for 1000 - 2000 lbs to be viable.

My understanding is that for Pegasus the cost of operating the host vehicle, Stargazer, turned out to be much greater than anticipated.

I'm blanking on the guy's name, but you can google it easily--hey! I just did that! Pegasus was designed by Dr. Antonio Elias. Anyway, he gave a great presentation at a big AIAA conference where he listed a number of key lessons learned, or "things you should not do" based upon their experience with Pegasus. I believe that one of them was that any air-launched vehicle should not require a dedicated launch vehicle that cannot perform any other mission or requires major modifications. The reason is that the rocket then has to carry the cost of the aircraft. That's a real cost hit for the program: that L-1011 sits on the ground most of the time, but you have to maintain it, you have to insure it, you have to pay pilots to fly it. Even if they are airline pilots, the L-1011 is now unique, so while they fly 777s for an airline, they have to maintain proficiency with the L-1011, so that costs money. Also, there are costs to the rocket itself because it has to be made "man-rated" because it is hanging under an airplane with people on it. That drives up the design and operational costs.

One of the things that is currently under development now is a towed glider aircraft for launching rockets. The logic of that is that a glider has no pilots and no major maintenance costs. So it does not cost a lot of money while sitting around not flying. And it is designed to be towed by a commercial Learjet that can otherwise go do useful things when not serving in an airlaunch capacity. And the rocket does not have to be "man-rated" because it never gets close to the piloted airplane. NASA is working on the concept, but is not actively developing it.

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Re: Stratolaunch
« Reply #106 on: May 31, 2017, 12:00:45 pm »
That's a lot of plane to launch a Pegasus XL (for now).

Offline sferrin

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Re: Stratolaunch
« Reply #107 on: June 02, 2017, 12:05:58 pm »
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Re: Stratolaunch
« Reply #109 on: July 19, 2017, 06:34:37 am »
Air Force secretary hints at military space applications for Stratolaunch super-plane

https://www.geekwire.com/2017/air-force-secretary-highlights-military-space-applications-stratolaunch-super-airplane/

Offline blackstar

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Re: Stratolaunch
« Reply #110 on: July 25, 2017, 09:19:40 pm »
Air Force secretary hints at military space applications for Stratolaunch super-plane

https://www.geekwire.com/2017/air-force-secretary-highlights-military-space-applications-stratolaunch-super-airplane/

"Today I had the chance to see firsthand how @Stratolaunch is developing an air-launch platform to make space more accessible"

Wait, that's it? That's the "hint"?

That's typical boilerplate language. It says nothing. It's neither negative nor an endorsement. She was being nice, that is all.

Offline Flyaway

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Re: Stratolaunch
« Reply #111 on: September 20, 2017, 09:47:51 am »
Engine test latest step for Stratolaunch’s giant aircraft

Quote
WASHINGTON — Stratolaunch announced Sept. 19 that the company has achieved another milestone in the development of a unique giant aircraft that will serve as a launch platform.

The company said that it successfully tested at its Mojave, California, facility the six Pratt & Whitney PW4056 turbofan jet engines that will power the aircraft. Each engine is capable of producing 56,750 pounds-force of thrust.

The engines came from two Boeing 747 jetliners that Stratolaunch acquired as part of the development of the one-of-its-kind plane. The engines, the company said in a statement, were put through a series of tests, including one where the engines were started one at a time and allowed to idle. “In these initial tests, each of the six engines operated as expected,” the company said.

http://spacenews.com/engine-test-latest-step-for-stratolaunchs-giant-aircraft/

Offline Foo Fighter

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Re: Stratolaunch
« Reply #112 on: September 21, 2017, 04:59:48 am »
This strikes me as an equivalent to the flying car that did not, went bust in the end.  The emperors new cloth's is another euphemism.

Offline sferrin

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Re: Stratolaunch
« Reply #113 on: September 21, 2017, 05:59:21 am »
This strikes me as an equivalent to the flying car that did not, went bust in the end.  The emperors new cloth's is another euphemism.

More like Hughes' "Spruce Goose".  (Allen's "Composite Albatross"?) Time will tell though. Hopefully it works out.
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Re: Stratolaunch
« Reply #114 on: September 21, 2017, 06:41:03 am »
No nose radomes and wing leading edges - seems, that aircraft requires further assembly.
We have a at least one commercially successful 6-engined prototype - Antonov An-225, so I hope to see Stratolaunch in action soon 8-)

Offline Hobbes

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Re: Stratolaunch
« Reply #115 on: September 21, 2017, 08:54:52 am »
Stratolaunch has been working on this for 6 years, and plan to put it into service in another 2. The Boeing 787 took 6 years from announcement to first flight, and 2 more years to finish flight testing. "Emperor's new clothes" is uncalled for.

Offline Mat Parry

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Re: Stratolaunch
« Reply #116 on: September 21, 2017, 10:00:52 am »
More like Hughes' "Spruce Goose".  (Allen's "Composite Albatross"?) Time will tell though. Hopefully it works out.

I'd love it to be more like a Howard Hughes Glomar explorer deception.

Sadly I think we can be certain it's not

Offline Byeman

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Re: Stratolaunch
« Reply #117 on: September 22, 2017, 10:59:35 am »
This strikes me as an equivalent to the flying car that did not, went bust in the end.  The emperors new cloth's is another euphemism.

More like Hughes' "Spruce Goose".  (Allen's "Composite Albatross"?) Time will tell though. Hopefully it works out.

I heard the perfect name for it, "Deuce Goose"

Offline Orionblamblam

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Re: Stratolaunch
« Reply #118 on: September 22, 2017, 04:22:35 pm »

I heard the perfect name for it, "Deuce Goose"

Better still: "Deus Goose."

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Offline sferrin

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Re: Stratolaunch
« Reply #119 on: October 07, 2017, 09:16:51 am »
More like Hughes' "Spruce Goose".  (Allen's "Composite Albatross"?) Time will tell though. Hopefully it works out.

I'd love it to be more like a Howard Hughes Glomar explorer deception.

Sadly I think we can be certain it's not

Maybe, like the B-52 / X-15, it could be a launch vehicle for testing things like these:





or maybe a test vehicle along the lines of this but for scramjets:

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Offline Mat Parry

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Re: Stratolaunch
« Reply #120 on: October 08, 2017, 02:45:23 pm »
No idea...

They're going to have to find something for it to do, because launching 3 Pegasus rockets at once is a ludicrous proposition (and a very unconvincing cover story for secret military space applications). With only ~5 Pegasus launches in the last decade, the demand is small.

It would seem to me that, rather than a guiding conspiracy, a series of events (largely involving the supplier of the proposed rocket boosters) have cascaded down to result in a dubious business model.

Then again, who knows...

1. All of a sudden the Chinese appear to want their own massive/impractical 6 engined beast (Antonov An-225 Mriya). Did something spook them into playing catch up off the shelf.

Or maybe

2. Northrop caught wind of a flourishing future market in secret rocket boosters for the military via stratolaunch and this contributed to their decision to buy orbital ATK.... if only we knew someone who knew about Northrop Grumman corporate strategy   :D

Please note, I'm joking about Northrop Grumman's acquisition of Orbital ATK.

Offline blackstar

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Re: Stratolaunch
« Reply #121 on: October 09, 2017, 04:50:00 pm »
No idea...

They're going to have to find something for it to do, because launching 3 Pegasus rockets at once is a ludicrous proposition (and a very unconvincing cover story for secret military space applications). With only ~5 Pegasus launches in the last decade, the demand is small.

It would seem to me that, rather than a guiding conspiracy, a series of events (largely involving the supplier of the proposed rocket boosters) have cascaded down to result in a dubious business model.

This is easy to understand if you look at it through the lens of a billionaire's ego:

-other billionaires had their own rockets
-he wanted his own rocket
-he also wanted it to be more spectacular than theirs
-so he dictated that it be launched from the world's largest aircraft

The end result is that the "solution" did not really have a market it was going to serve, and no way to serve an existing market more economically. But the rich guy still wants his big airplane.



Offline Mat Parry

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Re: Stratolaunch
« Reply #122 on: October 10, 2017, 11:44:21 am »
I think you're right.

I must admit I don't often pull the "billionaire ego lens" out of storage to look through! I guess Elon Musk has got me accustomed to thinking all billionaires are like Tony Stark, when infact some are more like.... well a bit orange coloured and far too fond of twitter.

Offline sferrin

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Re: Stratolaunch
« Reply #123 on: December 20, 2017, 09:01:07 am »
Apparently they've started taxiing the beast.
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Offline Archibald

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Re: Stratolaunch
« Reply #124 on: December 20, 2017, 10:59:32 am »
It will be an awesome flying machine, one can't deny that fact. Except it will be quite expensive and unuseful. But hell, Allen has a crapload of money, if he wants to sink it, his own business.

I wonder if it will go to Le Bourget Airshow someday. Albeit Le Bourget might be too small for such a beast.  :(
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Re: Stratolaunch
« Reply #125 on: December 20, 2017, 11:12:25 am »
Stratolaunch is basically a hobby for Paul Allen who has an estimated net worth of around $20 Billion.  I figure it is a more productive use of money versus a castle on a mountain top and has a more plausible chance of eventual profitability than a lot of the mega infrastructure/real estate projects I see around the world.


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Re: Stratolaunch
« Reply #126 on: December 20, 2017, 11:48:16 am »
I wonder how many MOABs you could hang under its wing and still fly the round trip over North Korea?
Cheers.

Offline Archibald

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Re: Stratolaunch
« Reply #127 on: December 20, 2017, 12:03:15 pm »
250 metric tons. A MOAB weight 10 tons. So that's 25 MOABs.
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Offline steelpillow

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Re: Stratolaunch
« Reply #128 on: December 20, 2017, 02:03:46 pm »
250 metric tons. A MOAB weight 10 tons. So that's 25 MOABs.

:o :o :o

My, there was me imagining a handful at best. You wouldn't need nukes with a Mother of All Bombers like that!
Cheers.

Offline Archibald

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Re: Stratolaunch
« Reply #129 on: December 22, 2017, 02:19:47 am »
Quote
You wouldn't need nukes with a Mother of All Bombers like that!

That's an understatement !  ;D
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Re: Stratolaunch
« Reply #130 on: February 19, 2018, 07:26:50 pm »
http://spacenews.com/pentagon-budget-funds-small-launch-services-to-gain-greater-access-to-space/

Quote
The Air Force creating a budget line for small launch is a “very good thing for the industry,” said Steve Nixon, vice president of strategic development at Stratolaunch.

Stratolaunch is developing the world’s largest aircraft platform and plans to launch Orbital ATK’s Pegasus vehicles into space for the first time in 2018, Nixon told SpaceNews. He said the services his company would offer fit the type of missions that the military is talking about, “Particularly the idea of having a resilient launch capability that could provide access to space in a contested environment.”
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Offline Flyaway

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Re: Stratolaunch
« Reply #131 on: February 26, 2018, 12:59:54 pm »
Quote
Just released new aerial and ground shots of the latest test series performed this weekend. More to come! stratolaunch.com/gallery.html

https://twitter.com/stratolaunch/status/968215041278291968

Offline sferrin

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Re: Stratolaunch
« Reply #132 on: February 26, 2018, 01:03:08 pm »
Can't wait to see it fly.  (Hopefully more than once.)
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Offline Archibald

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Re: Stratolaunch
« Reply #133 on: February 28, 2018, 03:55:13 am »
I'm confident there will be no accident. It's serious engineering. What is really not serious is the usefulness of that big thing... such a big aircraft to launch little Pegasus rockets. Just because nobody wanted to create a rocket to be launched from the aircraft. That's a little pathetic when you think about it.
Meh.
Then again, it's Paul Allen money, not mine. Plus one can't deny it's a beautiful aircraft, and quite impressive with that. I do hope it will fly to Le Bourget airshow someday.
« Last Edit: February 28, 2018, 03:57:02 am by Archibald »
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Offline sferrin

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Re: Stratolaunch
« Reply #134 on: February 28, 2018, 05:07:57 am »
I'm confident there will be no accident. It's serious engineering. What is really not serious is the usefulness of that big thing... such a big aircraft to launch little Pegasus rockets. Just because nobody wanted to create a rocket to be launched from the aircraft. That's a little pathetic when you think about it.
Meh.
Then again, it's Paul Allen money, not mine. Plus one can't deny it's a beautiful aircraft, and quite impressive with that. I do hope it will fly to Le Bourget airshow someday.

Yeah, it's a shame nobody has wanted to spend the money for a decent sized launcher for the thing.  Maybe they could use it as a test bed, like the B-52 at Edwards (or wherever that thing is based).
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Offline George Allegrezza

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Re: Stratolaunch
« Reply #135 on: February 28, 2018, 05:49:53 am »
It was always intended to have a big (~500K lb) launch vehicle to deploy.  The economics of that haven't panned out, it appears.

Offline sferrin

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Re: Stratolaunch
« Reply #136 on: February 28, 2018, 06:13:01 am »
It was always intended to have a big (~500K lb) launch vehicle to deploy.  The economics of that haven't panned out, it appears.

Right. Nobody wanted to pony up the money for the launcher, a launcher that would probably be over-priced if it's launch aircraft were for some reason unavailable.
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Offline Archibald

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Re: Stratolaunch
« Reply #137 on: February 28, 2018, 07:20:48 am »
The problem is that the aircraft, while giganormous, can't lift more than 250 mt of rocket. 250 mt is too light and small a rocket to compete with anything - Proton, F9R, Ariane 5 weights hundreds of tons, but that's what is needed to lift the huge GEO comsats... to GEO. Stratolaunch can't launch any meaningful payload to GEO, and that's the big problem.

As for LEO mega-constellations, it brings no credible advantage over, for example, Rocketlab Electron. Or F9R. Or even a freakkin' Soyuz.

The math was against them from day one. IMHO of course.

Then again, Paul Allen has plenty enough of dozens of billion of dollars to allow himself to be *wasteful* in such ventures.
« Last Edit: February 28, 2018, 07:25:08 am by Archibald »
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Offline steelpillow

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Re: Stratolaunch
« Reply #138 on: February 28, 2018, 11:29:08 am »
Maybe they can sling a huge cargo pod under there and compete with the An-225 Mriya in the heavy haulage sector.
Cheers.

Offline martinbayer

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Re: Stratolaunch
« Reply #139 on: February 28, 2018, 12:11:23 pm »
The rocket propelled Interim Hotol reusable spaceplane concept, see http://www.astronautix.com/i/interimhotol.html, had a gross mass of 250 metric tons and was designed to be launched from an An-225...

Martin
« Last Edit: February 28, 2018, 01:37:25 pm by martinbayer »
Would be marching to the beat of his own drum, if he didn't detest marching to any drumbeat at all so much.

Offline sferrin

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Re: Stratolaunch
« Reply #140 on: February 28, 2018, 01:42:57 pm »
Maybe they can sling a huge cargo pod under there and compete with the An-225 Mriya in the heavy haulage sector.

But how many runways are wide enough for the landing gear?
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Offline Flyaway

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Re: Stratolaunch
« Reply #141 on: March 07, 2018, 02:09:19 pm »
Why is Paul Allen building the world’s largest airplane? Perhaps to launch a space shuttle called Black Ice.

Quote
But Allen has even bigger ambitions for Stratolaunch and is considering pairing it with a new space shuttle that’s known inside the company as Black Ice.

Quote
The Black Ice space plane — should it be built — would be about as big as the former space shuttle developed by NASA and capable of staying up for at least three days. It could be launched from virtually anywhere in the world, as long as the runway could accommodate Stratolaunch’s size. And it would be capable of flying to the International Space Station, taking satellites and experiments to orbit, and maybe one day even people — though there are no plans for that in the near-term.

Then it would land back on the runway, ready to fly again.

https://www.washingtonpost.com/news/the-switch/wp/2018/03/06/why-is-paul-allen-building-the-worlds-largest-airplane-perhaps-to-launch-a-space-shuttle-called-black-ice/?utm_term=.978390de27c8

Offline Flyaway

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Re: Stratolaunch
« Reply #142 on: April 16, 2018, 02:02:07 pm »
Stratolaunch planning first aircraft flight this summer

Quote
Stratolaunch expects to conduct the first flight of its giant aircraft this summer as it develops a broad spectrum of launch services that will make use of it, the company said April 16.

Stratolaunch has performed two taxi tests of the aircraft at the Mojave Air and Space Port in California so far, most recently in late February. Three more taxi tests of the vehicle are planned according to company officials, speaking on background during the 34th Space Symposium here.

Those taxi tests will take place at progressively higher speeds. During the most recent test, the plane reached speeds of up to 74 kilometers per hour. The next test will reach speeds of nearly 130 kilometers per hour, with later tests going up to 220 kilometers per hour.

http://spacenews.com/stratolaunch-planning-first-aircraft-flight-this-summer/

Offline Archibald

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Re: Stratolaunch
« Reply #143 on: April 16, 2018, 11:09:37 pm »
Quote
http://spacenews.com/stratolaunch-planning-first-aircraft-flight-this-summer/



Whooooooooooooohooooooooo !!! I want to see that thing flying, even if it is mostly a pointless vanity project.
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Offline TomcatViP

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Re: Stratolaunch
« Reply #144 on: April 17, 2018, 02:43:23 am »
Quote
However, the company is making clear it has other uses for that aircraft than launching the Pegasus.

Someone should put them in contact with the Belgian air force... Just in case they are forced to keep soldiering with their F-16 any longer.

Offline Michel Van

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Re: Stratolaunch
« Reply #145 on: April 17, 2018, 03:06:16 am »
Hell yeah i wanna see the Stratolaunch take off fly around airfield and lands, with Blur Song 2 as soundtrack on Youtube

Someone should put them in contact with the Belgian air force... Just in case they are forced to keep soldiering with their F-16 any longer.

ROFL
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Offline Flyaway

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Re: Stratolaunch
« Reply #146 on: August 20, 2018, 09:03:01 am »
Quote
Stratolaunch has confirmed what most people have long speculated: it’s developing its own launch vehicles for its air-launch system, including a reusable space plane that could eventually carry people.

https://twitter.com/jeff_foust/status/1031549089828286464

In-depth Wired piece about the background of Stratolaunch.

https://www.wired.com/story/stratolaunch-airplane-burt-rutan-paul-allen/

Offline Archibald

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Re: Stratolaunch
« Reply #147 on: August 20, 2018, 09:51:13 am »
Not much new information bar the Roc origins (the cockpit was to be on the tail ? WTH ? it would like a giant Pond Racer ! )



With or without air launch, if that Black Ice is to be a SSTO, then the propellant mass fraction remain as tricky as in the day of the Venture Star.
If LOX/LH2, 92% of the SSTO drop mass (not launch mass !) shall be propellants. If not LH2, then it is 95%.

Starting from the Roc payload of 250 metric tons, either it mass less 21 metric tons or less, with empty tanks, otherwise it never goes into orbit. As simple as that ! Those 21 tons shall include a) the propellant tanks around the propellants b) the airframe around the tanks and c) whatever payload can be shoehorned into such a vehicle.

Air launch provides merely shaves 1 km/s of delta-v out of the 10 km/s. 10% ain't much, and what worse, the rocket equation has a logarithm stuck inside it, so it is even less than that.

Then again, maybe this time it will work. For the record, Musk BFS, even with the big BFR under it (hence a TSTO) will have a SSTO-like prop mass fraction because it needs it to go from LEO to lunar surface and back with a decent payload. On paper at least. So let's see what Musk do with BFS. 

A mini--BFS air dropped from the Roc would be quite a sight !
« Last Edit: August 20, 2018, 10:04:21 am by Archibald »
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Offline fredymac

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Re: Stratolaunch
« Reply #148 on: August 20, 2018, 11:11:12 am »
Given the size of the motherplane, the shuttle will be big and apparently unmanned.

Offline steelpillow

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Re: Stratolaunch
« Reply #149 on: August 20, 2018, 11:49:09 am »
No reusable space plane can make it as a single-stage payload from a subsonic launcher. The energy saving over a ground launch is not as big as most people think. As a minimum it would require a suborbital second stage of some description, be it Shuttle-style external tank, Virgin-style spaceplane  or plain old-fashioned Pegasus-style rocket stage. The rockets in the graphic might be good for varying payload sizes, with each step larger representing lower cost, but the orbital spaceplane depicted is just fantasy art.
Cheers.

Offline Flyaway

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Re: Stratolaunch
« Reply #150 on: August 20, 2018, 01:52:21 pm »
Bit more info here.

Finally, the biggest airplane in the world has some rockets to launch

https://arstechnica.com/science/2018/08/stratolaunch-announces-not-one-but-an-entire-fleet-of-rockets/

Offline blackstar

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Re: Stratolaunch
« Reply #151 on: August 21, 2018, 07:42:49 pm »
No reusable space plane can make it as a single-stage payload from a subsonic launcher. The energy saving over a ground launch is not as big as most people think.

Yeah, there's a reason that during the entire history of the space age there have been few attempts at air launch, and nothing really commercially successful. Pegasus is the only one that has stuck around, and its launch rate is so low that it's hard to believe it makes any money--imagine the cost simply to keep that L1011 certified year-round--and has probably been kept going just so Orbital could keep its foot in the door. (The guy who created Pegasus has written and spoken at lectures and been very blunt about how it has not worked out. In nearly 30 years it has launched as many payloads as they originally planned to launch within the first couple of years of service.)

It's not just physics that work against this, however. Launch sites also support launch vehicle and payload preparation. They have facilities (equipment) and people. If you launch from a plane, you're still going to need fixed facilities for rocket and payload processing. You're going to encapsulate your spacecraft in a clean room, and keep it powered and cooled. And you're going to need reliable equipment and facilities to do that. Range support has gotten a lot more flexible, which helps air launch. But another thing hurting Stratolaunch is that the plane is so big that it is going to be limited from where it can operate. It's not like they're going to fly that out of any airport with a long runway.

So it then comes back to the question of why anybody would want to do this? What's the advantage? They're not going to stage the plane from many places, and how far is it going to fly from its staging airfield to launch a rocket? What does that give you that you cannot already get from a fixed location? And with SpaceX able to launch bigger rockets for less money, is it possible to simply get what you need by using a bigger rocket than you normally would?


Offline fredymac

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Re: Stratolaunch
« Reply #152 on: August 22, 2018, 06:19:09 am »
Paul Allen is 65 years old so he probably still has most of his brainpower intact.  Someone convinced him to spend big money to find out if air launching can become a winning launch business.  Of course, a person who knows software can also be a fool as well.  Luckily, the bill to determine which it is will be his alone and the rest of us can sit back and enjoy the spectacle.

Offline steelpillow

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Re: Stratolaunch
« Reply #153 on: August 22, 2018, 09:08:41 am »
So it then comes back to the question of why anybody would want to do this?
Quite a few reasons, really.

Cryogenic liquid fuel boiloff is one reason. Approx 10% of any LOX/LH2 fuel load will boil off during the initial stages of launch and its tankage is just dead weight. A mothership can keep it topped up, allowing the later-stage tanks to be 10% smaller. That allows a significantly bigger payload and/or higher orbit.

Operational flexibility is another. You can fly round inconvenient weather patterns to find an open window, not have to wait for it to come to you. You can fly to an optimal launch spot and add a few mph in the optimal direction: different orbits are best reached in different ways and you are not tied to one spaceport's way. You can resupply and relaunch quickly, reducing the number of launchers needed to support a busy schedule.

Economy of operation is yet a third. Several of those flexibility options also offer significant cost savings and/or heavier payloads. More significantly, if you have a delicate payload such as space tourists, your gee force is severely limited and a rocket must waste an age hanging in the sky burning gargantuan amounts of fuel. Substituting aerodynamic lift for the thirstiest flight segment offers equally gargantuan cost savings. It's not so important if you can pile on those gees for a robust payload, a rocket first stage then makes a lot more sense.

Pegasus is a commercial failure largely because piling lots of small payloads into the spare corners around big ones has turned out a lot cheaper than launching them all individually.

All in all, I think that the mothership is a great piece of technology. The thinking behind the orbiter suite has its flaws, but a mix of "super-size Pegasus" for at least some economy of scale, and multi-stage spaceplane (forget all-in-one) for the first low-gee launch service, might just prove viable.
« Last Edit: August 22, 2018, 09:18:18 am by steelpillow »
Cheers.

Offline Hobbes

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Re: Stratolaunch
« Reply #154 on: August 22, 2018, 10:52:19 am »
1. 10% of boiloff in the ~2 minutes that the stage runs? For an F9 that's 50 tons of LOX changing phase. That seems far higher than the boiloff observed in the minutes before launch.
2. You might be able to fly around weather patterns, but you still have to apply for an exclusion zone where your first stage will impact (and make sure that zone is actually empty before you launch).
3. G-load is highest at stage burnout, lowest at takeoff. Replacing the first 30 seconds of the launch with an airplane ride doesn't gain you anything there.

Offline blackstar

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Re: Stratolaunch
« Reply #155 on: August 22, 2018, 11:06:00 am »
A mothership can keep it topped up, allowing the later-stage tanks to be 10% smaller. That allows a significantly bigger payload and/or higher orbit.

So this aircraft is equipped to top off the tanks of a rocket carried under the wing?

Offline steelpillow

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Re: Stratolaunch
« Reply #156 on: August 23, 2018, 09:30:49 am »
1. 10% of boiloff in the ~2 minutes that the stage runs? For an F9 that's 50 tons of LOX changing phase. That seems far higher than the boiloff observed in the minutes before launch.
2. You might be able to fly around weather patterns, but you still have to apply for an exclusion zone where your first stage will impact (and make sure that zone is actually empty before you launch).
3. G-load is highest at stage burnout, lowest at takeoff. Replacing the first 30 seconds of the launch with an airplane ride doesn't gain you anything there.

1. What you see before launch is only the water vapour and ice crystals condensed out of the air by the cold gases, the volume of cold gas roaring out of the vents is a lot higher.
2. Not if your first stage uses runways. You probably mean second stage, but that is no different from a rocket so not relevant to any comparison.
3. No. Replacing the 1st stage with a plane avoids the G load peak at first stage burnout. Other, wasteful techniques are necessary to reduce peak G for the later stages, but those are not the supremely thirsty stages.

So this aircraft is equipped to top off the tanks of a rocket carried under the wing?
Probably not. But it would hardly be rocket science to modify it. Think of it as an option in case a cryogenically-fuelled payload comes along.
« Last Edit: August 23, 2018, 09:32:27 am by steelpillow »
Cheers.

Offline Michel Van

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Re: Stratolaunch
« Reply #157 on: August 23, 2018, 11:21:13 am »
here is Scott Manley analysis of Stratolaunch with help of Kerbal

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Offline TomcatViP

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Re: Stratolaunch
« Reply #158 on: August 23, 2018, 12:14:55 pm »
Don't forget that Stratolaunch will service the rocket industry like transporting bulky components from one place to another relatively more easily than piggy backing it on an aircraft that would age faster (used airframe) and invariably requests more dedicated maintenance and logistics.

Also, the possibility to escape somewhat the uncertainty linked to the weather plaguing launch sites helps you to narrow your launch windows, relocate from northern to equatorial hemisphere, disseminate your launch across various site to face regulations and meet better any time constraints that might prove critical.

I think that for a national industry that has cut itself de facto from foreign cooperation, a service like Stratolaunch could be able to provide will invariably meet a market. Now, it might be that it is all that matters to continue pouring money in the project.   
« Last Edit: August 23, 2018, 04:45:57 pm by TomcatViP »

Offline Hobbes

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Re: Stratolaunch
« Reply #159 on: August 23, 2018, 12:27:07 pm »
1. 10% of boiloff in the ~2 minutes that the stage runs? For an F9 that's 50 tons of LOX changing phase. That seems far higher than the boiloff observed in the minutes before launch.
2. You might be able to fly around weather patterns, but you still have to apply for an exclusion zone where your first stage will impact (and make sure that zone is actually empty before you launch).
3. G-load is highest at stage burnout, lowest at takeoff. Replacing the first 30 seconds of the launch with an airplane ride doesn't gain you anything there.

1. What you see before launch is only the water vapour and ice crystals condensed out of the air by the cold gases, the volume of cold gas roaring out of the vents is a lot higher.
2. Not if your first stage uses runways. You probably mean second stage, but that is no different from a rocket so not relevant to any comparison.
3. No. Replacing the 1st stage with a plane avoids the G load peak at first stage burnout. Other, wasteful techniques are necessary to reduce peak G for the later stages, but those are not the supremely thirsty stages.


I wrote my previous post assuming that they would launch a two-stage rocket. You seem to be assuming they'll use a single-stage rocket. The announcement doesn't say either way. A single-stage rocket would be a very ambitious strategy - something nobody has pulled off yet.

1. too tired to do the math right now. I do have one data point: in expander-cycle engines, the LOX has to be heated to provide enough tank pressure. 50 tons of boiloff in 2 minutes would be easily enough to provide tank pressure without extra heating. That suggests the figure is too high.

2. I mean the first rocket stage, obviously. And you need to file a NOTAM for ALL rocket stages that crash on land/in the ocean. You were suggesting flexibility of operations by responding to weather. I'm saying they can't do that because they have to file NOTAMs with so much lead time they can't adjust their flight plan en-route.

3. The aircraft is not a replacement for the first stage. It just makes the first stage a bit smaller. An F9 first stage separates at 1600 m/s. This aircraft will go maybe 300 m/s. If you could air-launch a Falcon 9, you'd make the first stage 20% shorter. That's all the savings you get from a subsonic air launch.

2 and 3 would be different if the rocket were to be a single-stage design.

Looking at the drawings, there are several horizontal lines that suggest to me it's a 2-stage vehicle.



« Last Edit: August 23, 2018, 12:35:59 pm by Hobbes »

Offline blackstar

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Re: Stratolaunch
« Reply #160 on: August 23, 2018, 01:43:44 pm »
So this aircraft is equipped to top off the tanks of a rocket carried under the wing?
Probably not. But it would hardly be rocket science to modify it. Think of it as an option in case a cryogenically-fuelled payload comes along.

In other words, no.


Offline steelpillow

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Re: Stratolaunch
« Reply #161 on: August 24, 2018, 01:08:40 am »
You seem to be assuming they'll use a single-stage rocket.

No, I make no such assumption. You are evidently arguing against something I have not said.

Don't forget that an air launch is a much lower-gee affair than a rocket launch. The F9 is a poor comparison because it is a relatively high-gee rocket system and therefore inherently more efficient than say the Shuttle. You just do those sums, and see how F9 fares as a low-gee launch platform!

Oh, and I'm sure that the bureaucracy is capable of catching up with the reality, should the need arise. Why are you so down on the whole idea that you have to invoke tickboxes?
Cheers.

Offline steelpillow

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Re: Stratolaunch
« Reply #162 on: August 24, 2018, 01:15:03 am »
So this aircraft is equipped to top off the tanks of a rocket carried under the wing?
Probably not. But it would hardly be rocket science to modify it. Think of it as an option in case a cryogenically-fuelled payload comes along.

In other words, no.
But a tad more informative.
Cheers.

Offline Hobbes

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Re: Stratolaunch
« Reply #163 on: August 24, 2018, 02:09:15 am »
Don't forget that an air launch is a much lower-gee affair than a rocket launch. The F9 is a poor comparison because it is a relatively high-gee rocket system and therefore inherently more efficient than say the Shuttle. You just do those sums, and see how F9 fares as a low-gee launch platform!

When designing a rocket, G levels are set to be as high as possible without damaging the payload. This is done to reduce gravity losses: at lower acceleration, you spend more time at suborbital speeds and your launch will ultimately cost more fuel.
Whether you launch at 0 m/s or 300 m/s doesn't change that.
Check the user guide for the air-launched Pegasus rocket for instance, G-forces at stage burnout are 9G for the first stage (much higher than the F9, by the way).

Quote
Oh, and I'm sure that the bureaucracy is capable of catching up with the reality, should the need arise.

It's not a matter of bureaucracy. Dropping a spent rocket stage on someone's head is a surefire way to bankrupt your business. I don't see Stratolaunch buying an MPA to scout their last-minute-changed landing zone, so they have to use the existing legal mechanism of NOTAMs, which take a while to result in a cleared area.

Offline Zootycoon

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Re: Stratolaunch
« Reply #164 on: August 24, 2018, 04:05:52 am »
Steelpillow
Your claim that up to ten percent of a cryogenic propellant is lost at time of burn out due to evaporation – Ref Text Book “Modern Engineering for Design of Liquid –Propellant Rocket Engines” by Dieter K Huzel, page 146 Para 5.3, quotes “Rate of oxidizer evaporation in the tank as 1.6lb/s” for a relatively large 4 engine powered LOX/RP1 stage. This is about four/five orders less than your claim so please can you provide a referable source to support your claim.
 
Every aircraft I’ve ever come across has had operating limits, e.g. crosswind limits, hot/high limits, contaminated surface limits, etc. So it makes no difference how good the weather is at the desired launch location, if the weather at airfield is outside of operating limits, the mission doesn’t get flown. I guess in theory you could say the planning could be more flexible but that’s making the assumption that airports are really going to accept a 0.1 - 0.2 kilo ton bomb siting on their main runway, which if it goes bang would be a single point failure for their entire revenue income. An airport with population living under the flight path I reckon will be an automatic exclusion.
 
Others and myself cannot understand how an air launch reduces the max flight g, in particularly considering the additional pitch up which inherently occurs after release. Maybe you could provide a referable source to support your claim which can explain it better.
 
Your claim that that automatic loading of cryogenic propellant in flight is “not rocket science”;-  the USAF blew up seven ICBM’s (Titan 1 and Atlas) complete with their silo’s during operational propellant loading exercises. (Although according to Dieter’s data above, it’s unnecessary so not worth the risk)
 
Why these concepts get developed?
When it comes to developing technology cash is king. Just because an entrepreneur is mega wealthy doesn’t automatically mean they has a good understanding of even simple physic’s or will even listen to the advice of someone that does;- they’re notorious for going with their “gut” combined with a dogmatic, get on with it attitude. Once cash is being spent and loyal people are on the payrole, they become very vulnerable to the “Emperor’s New Clothes” situation.  This has been responsible for a good number of spectacular white elephants in years gone by.
 
However enticing that the thought that a commercial airliner can achieve 10% of the altitude required for orbit, it’s an inescapable fact that it only has a tiny fraction of the required orbital energy. This is best illustrated by the orbital mass fraction of the vehicle at zero V, which is barely different for both methods.

Offline sferrin

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Re: Stratolaunch
« Reply #165 on: August 24, 2018, 04:46:36 am »
Don't forget that an air launch is a much lower-gee affair than a rocket launch. The F9 is a poor comparison because it is a relatively high-gee rocket system and therefore inherently more efficient than say the Shuttle. You just do those sums, and see how F9 fares as a low-gee launch platform!

When designing a rocket, G levels are set to be as high as possible without damaging the payload.

Why is the Delta IV Heavy so damn slow?  I swear, by the time it reaches Mach 1 the Space Shuttle would have already shed it's boosters.
"DARPA Hard"  It ain't what it use to be.

Offline Hobbes

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Re: Stratolaunch
« Reply #166 on: August 24, 2018, 07:42:04 am »
Off the cuff as I haven't studied this: compromised design because they wanted to reuse the Delta IV core?

Offline Archibald

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Re: Stratolaunch
« Reply #167 on: August 24, 2018, 09:02:46 am »
Don't forget that an air launch is a much lower-gee affair than a rocket launch. The F9 is a poor comparison because it is a relatively high-gee rocket system and therefore inherently more efficient than say the Shuttle. You just do those sums, and see how F9 fares as a low-gee launch platform!

When designing a rocket, G levels are set to be as high as possible without damaging the payload.

Why is the Delta IV Heavy so damn slow?  I swear, by the time it reaches Mach 1 the Space Shuttle would have already shed it's boosters.

Because the RS-68 are LH2 engines of far lower thrust than SRBs. SRBs are brute force and raw power. The difference is similar to a 300 hp sport car and a 300 hp diesel truck. SRB are rather sport car, they go fast but are pretty short lived or short range. LH2 starts slowly but once at max power, it rules the skies.
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Offline sferrin

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Re: Stratolaunch
« Reply #168 on: August 24, 2018, 09:19:35 am »
Don't forget that an air launch is a much lower-gee affair than a rocket launch. The F9 is a poor comparison because it is a relatively high-gee rocket system and therefore inherently more efficient than say the Shuttle. You just do those sums, and see how F9 fares as a low-gee launch platform!

When designing a rocket, G levels are set to be as high as possible without damaging the payload.

Why is the Delta IV Heavy so damn slow?  I swear, by the time it reaches Mach 1 the Space Shuttle would have already shed it's boosters.

Because the RS-68 are LH2 engines of far lower thrust than SRBs. SRBs are brute force and raw power. The difference is similar to a 300 hp sport car and a 300 hp diesel truck. SRB are rather sport car, they go fast but are pretty short lived or short range. LH2 starts slowly but once at max power, it rules the skies.

I'm not asking HOW (I'm aware of the differences in T/W between the two) I'm asking WHY.  If the G levels should be as high as possible why did they go so low with the Delta IV. 
"DARPA Hard"  It ain't what it use to be.

Offline steelpillow

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Re: Stratolaunch
« Reply #169 on: August 24, 2018, 10:30:07 am »
@Zootycon
I don't have refs to hand but boiloff of H2 is far higher than that of LOX. See here for a suggestion of 300-500 Kg/min, around 10 times the number given by Huzel. Also, H2 is far lighter, so that weight represents a much bigger proportion of the total load. That's possibly where a couple of orders went. If I am still way out then maybe I am a bit dated - standards of insulation have improved over the years.

Your arguments against cryo fuel safety apply equally to rockets. Stratolaunch is not intended to operate from airports, for one thing it is too big to fit. The UK has pencilled in a couple of spaceports where cryo beasts may safely hog the departure lounge, I believe the US already has several. Plane takeoffs are less disrupted by weather than rocket launches. Sorry, but all that airport spiel is just a non-argument.

A plane does not reduce gee in and of itself, nobody is saying it does. What it does do is allow you to reduce max gee up to first stage separation* without hanging a massive booster stage from its own skyhook.

You need an example of reliable in-flight cryo transfer? Try the Space Shuttle.

* Just to be clear, I count a launch aircraft as a first stage.
« Last Edit: August 24, 2018, 10:36:01 am by steelpillow »
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Offline steelpillow

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Re: Stratolaunch
« Reply #170 on: August 24, 2018, 10:41:20 am »
talk about a heateddebate (runs for cover)

Just you wait 'til we start talking re-entry shielding ;D (ducks under said shielding)
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Offline Hobbes

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Re: Stratolaunch
« Reply #171 on: August 24, 2018, 11:02:12 am »


A plane does not reduce gee in and of itself, nobody is saying it does. What it does do is allow you to reduce max gee up to first stage separation* without hanging a massive booster stage from its own skyhook.

* Just to be clear, I count a launch aircraft as a first stage.

What you don't seem to grasp is that "reduce max gee up to first stage separation" is not necessary. No launch vehicle experiences its peak G-load at speeds between 0 and 300 m/s, it experiences peak G-load at burnout of the first rocket stage.

Offline steelpillow

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Re: Stratolaunch
« Reply #172 on: August 24, 2018, 11:59:10 am »
A plane does not reduce gee in and of itself, nobody is saying it does. What it does do is allow you to reduce max gee up to first stage separation* without hanging a massive booster stage from its own skyhook.

* Just to be clear, I count a launch aircraft as a first stage.

What you don't seem to grasp is that "reduce max gee up to first stage separation" is not necessary. No launch vehicle experiences its peak G-load at speeds between 0 and 300 m/s, it experiences peak G-load at burnout of the first rocket stage.
I think you will find my remarks consistent with that.
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Offline Hobbes

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Re: Stratolaunch
« Reply #173 on: August 24, 2018, 12:14:30 pm »
Then why offer that point as an advantage of air launch?

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Re: Stratolaunch
« Reply #174 on: August 24, 2018, 12:39:15 pm »
Then why offer that point as an advantage of air launch?
Because it reduces the size of the skyhook you need for the first rocket stage, if you are going for a low-gee trajectory. Have you done your low-gee sums on the Falcon 9 yet?
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Offline Zootycoon

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Re: Stratolaunch
« Reply #175 on: August 24, 2018, 01:39:41 pm »
An anonymously posted spiel on an Internet chat room is not a reliable technical reference.
« Last Edit: August 28, 2018, 02:14:18 pm by Zootycoon »

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Re: Stratolaunch
« Reply #176 on: August 25, 2018, 02:54:14 am »
So having the lightest weight skyhook on an air launch is an advantage over not needing such a thing on a vertical launch?
No. The air launch allows a reduction in the amount of rocket fuel that needs to be carried, to support the longer-period trajectory of a lower-gee orbital injection. The "skyhook" is a metaphor to try and get across the fundamental significance of time spent under both gravity and rocket power. You are not stupid, you know that very well. I fear you deliberately misread my statements in order to wind me up. That is disgusting of you.

Maybe by now you realize that he's not really a serious poster. Look at all the claims he made. They're all just... not serious.
Don't be absurd. I have answered every confused query with technically correct detail. Some of you have misunderstood what I wrote and others have questioned it, but it is you who are now totally losing the plot.

To recap. Somebody asked why people went in for launch aircraft like Stratolaunch. I attempted to answer that query. Whether the protagonists of launch aircraft are ultimately right or wrong, that is what they have argued, from Eugene Sanger to the Mriya-HOTOL composite to Pegasus to WhiteKnight to Stratolaunch. In explaining their case I have been subject to aggressive questioning, seemingly wilful misunderstanding, and now outright ridicule. I am sorry, but that is not acceptable.
« Last Edit: August 25, 2018, 08:44:07 am by steelpillow »
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Offline Hobbes

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Re: Stratolaunch
« Reply #177 on: August 25, 2018, 04:42:21 am »
If I came across as aggressive, I apologize. That was not my intent.

You made some claims that seemed optimistic or incorrect to me, based on my understanding of the physics involved, so I wrote some posts disagreeing with what you said. Those posts are my attempt to get a better understanding of what's going on, and I wrote them with the understanding that I might turn out to be incorrect.
Similarly, any misunderstandings on my part were genuine. I'm not in the habit of arguing to wind somebody up.

I tend to take people literally, so when you mentioned 'Skyhook' the thought that that might be a metaphor didn't cross my mind.

Offline Hobbes

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Re: Stratolaunch
« Reply #178 on: August 25, 2018, 06:10:48 am »

Cryogenic liquid fuel boiloff is one reason. Approx 10% of any LOX/LH2 fuel load will boil off during the initial stages of launch and its tankage is just dead weight. A mothership can keep it topped up, allowing the later-stage tanks to be 10% smaller. That allows a significantly bigger payload and/or higher orbit.


I found some boiloff calculations for the Shuttle external tank.

0.2 kg per second of LH2.  720 kg per hour loss.   106.26 tonnes - 6 days.
0.1 kg per second of LOX.   360 kg per hour loss.  629.34 tonnes - 73 days.

During the initial filling of the tank, boiloff is a lot higher: only 56% of the supplied LOX makes it into the tank, the rest is lost as boiloff during filling (cooling the tank from ambient to LOX temperature) and other waste. But once the tank is full and at equilibrium temperature, boiloff is 0.3 ton/hour for the Shuttle ET (which contains 600 tons of LOX). For a smaller rocket the boiloff will be higher, but we're quite a few orders of magnitude away from 10% boiloff in a few minutes.

Offline steelpillow

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Re: Stratolaunch
« Reply #179 on: August 25, 2018, 08:41:24 am »
@Hobbes,
Ah, found my problem. The 10% relates to the boiloff from a cryo rocket being carried for a nominal 1 hr to its drop site by a launch plane. It is not directly comparable to even a low-gee vertical rocket stage. It also assumes a higher rate of heat loss ca. 500 W/m2, which is out of date as I began to suspect. Was from a conversation I had many years ago during the HOTOL era.
The 100 W/m2 transfer rate in the study you draw on looks around half what it should be at any reasonable atmospheric pressure, judging by the sources it cited, so that may explain the rest of the gap.
Overall you appear to be a lot more right than I was. I hope that clears this one up.

My other comments stand.
« Last Edit: August 25, 2018, 08:46:03 am by steelpillow »
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Offline Zootycoon

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Re: Stratolaunch
« Reply #180 on: August 25, 2018, 10:30:44 am »
Steelpillow
I made very polite request for you to support your case with good technical sources or a reference which explains it clearly, but failed to do this, instead responding with a ref made to an anonymous person on a chat room (which was an order of magnitude difference to your original claim???), more unsupported opinions, dismission of my suggestion with a profanity, jargon? (The wiki description of a Skyhook is nothing like yours), insults, claims of victimisation and final name dropping.

Apologies ? I never intended to be aggressive or wind you up....Maybe you need to consider your conduct.




Offline Jemiba

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Re: Stratolaunch
« Reply #181 on: August 25, 2018, 11:59:49 pm »
So, back to topic, please, and maybe for a while at least, thinking twice, what a post can mean to others.
Such a discussion hasn't to be free of humour or irony, but those stylistic devices can quite easily be misunderstood.

It takes a long time, before all mistakes are made ...

Offline PaulMM (Overscan)

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Re: Stratolaunch
« Reply #182 on: August 26, 2018, 01:52:44 am »
My understanding of the economics of air launch is it is advantageous primarily for small payloads, where atmospheric drag is a relatively big factor.  Drag is proportional to surface area so simple geometry makes it less important to large rockets due to scaling between area and volume. I've not studied it in any detail however.
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Offline Byeman

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Re: Stratolaunch
« Reply #183 on: September 05, 2018, 09:44:43 am »

Cryogenic liquid fuel boiloff is one reason. Approx 10% of any LOX/LH2 fuel load will boil off during the initial stages of launch


Not true at all. There is little to not boil off in the short time from launch to orbit.

Offline Byeman

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Re: Stratolaunch
« Reply #184 on: September 05, 2018, 09:50:50 am »

1.  Operational flexibility is another. You can fly round inconvenient weather patterns to find an open window, not have to wait for it to come to you. You can fly to an optimal launch spot and add a few mph in the optimal direction: different orbits are best reached in different ways and you are not tied to one spaceport's way. You can resupply and relaunch quickly, reducing the number of launchers needed to support a busy schedule.

2.  Economy of operation is yet a third. Several of those flexibility options also offer significant cost savings and/or heavier payloads. More significantly,

3. if you have a delicate payload such as space tourists, your gee force is severely limited and a rocket must waste an age hanging in the sky burning gargantuan amounts of fuel.

4.  Substituting aerodynamic lift for the thirstiest flight segment offers equally gargantuan cost savings. It's not so important if you can pile on those gees for a robust payload, a rocket first stage then makes a lot more sense.


1.  No, still limited to a launch range.  And no, resupply and relaunch is not a given nor proven.

2.  No, none of those provide cost savings nor heavier payload.  Replacing the L1011 with a solid motor as in Taurus provides more performance.

3.  Not true.  Vertical rockets are not g limited.  Horizontal flight put more loads on payloads. 

4.  Unproven.

Not one of your statements is backed by data.

Offline fredymac

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Re: Stratolaunch
« Reply #185 on: September 05, 2018, 11:30:48 am »
Air launch doesn’t seem to provide an obvious advantage but you have 2 new business startups pursuing this architecture with serious money.  There are also examples of air launched ballistic missiles and targets.  Something must be advantageous about this approach and I would be very surprised if trade studies vs ground launch hadn’t been analyzed before money was committed.

The altitude advantage appears to be minor.  Compared to the eventual orbital altitude, the removal of 6 miles seems trivial.  Launch speed has the same issue of being so low compared to the final orbital velocity.  The lower air friction at high altitude might be useful but rockets tend to lift off slowly during their initial climb out so I wouldn’t think it would amount to very much.

At the rudimentary level, for a ground launched rocket to reach the altitude/velocity of an air launch, it would have to expend the fuel to power maximum thrust for 15 to 30 seconds.  If you remove the fuel/tankage structure/engine power margin to do this, just how much do you gain?

Offline steelpillow

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Re: Stratolaunch
« Reply #186 on: September 05, 2018, 12:21:17 pm »
Not one of your statements is backed by data.

Nor are any of yours. Eugene Sanger, B.Ae, Pegasus, Scaled Composites, Virgin Galactic and Stratolaunch have all thought your views to be rubbish. I am inclined to agree with them.
« Last Edit: September 05, 2018, 12:47:28 pm by steelpillow »
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Offline Byeman

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Re: Stratolaunch
« Reply #187 on: September 05, 2018, 12:26:09 pm »
Air launch doesn’t seem to provide an obvious advantage but you have 2 new business startups pursuing this architecture with serious money.  There are also examples of air launched ballistic missiles and targets.  Something must be advantageous about this approach and I would be very surprised if trade studies vs ground launch hadn’t been analyzed before money was committed.

The altitude advantage appears to be minor.  Compared to the eventual orbital altitude, the removal of 6 miles seems trivial.  Launch speed has the same issue of being so low compared to the final orbital velocity.  The lower air friction at high altitude might be useful but rockets tend to lift off slowly during their initial climb out so I wouldn’t think it would amount to very much.

At the rudimentary level, for a ground launched rocket to reach the altitude/velocity of an air launch, it would have to expend the fuel to power maximum thrust for 15 to 30 seconds.  If you remove the fuel/tankage structure/engine power margin to do this, just how much do you gain?

The mobility is the advantage.   There is a slight benefit for lower atmospheric density for the motor, the added altitude is negligible.

Offline steelpillow

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Re: Stratolaunch
« Reply #188 on: September 05, 2018, 12:43:25 pm »
Air launch doesn’t seem to provide an obvious advantage but you have 2 new business startups pursuing this architecture with serious money.  There are also examples of air launched ballistic missiles and targets.  Something must be advantageous about this approach and I would be very surprised if trade studies vs ground launch hadn’t been analyzed before money was committed.

The altitude advantage appears to be minor.  Compared to the eventual orbital altitude, the removal of 6 miles seems trivial.  Launch speed has the same issue of being so low compared to the final orbital velocity.  The lower air friction at high altitude might be useful but rockets tend to lift off slowly during their initial climb out so I wouldn’t think it would amount to very much.

At the rudimentary level, for a ground launched rocket to reach the altitude/velocity of an air launch, it would have to expend the fuel to power maximum thrust for 15 to 30 seconds.  If you remove the fuel/tankage structure/engine power margin to do this, just how much do you gain?

That's all about right. According to the HOTOL technical manager, air-launching it would have saved around 10-15% overall (and much of that due to topping-up boiloff), but of course that has to be offset against the carrier craft. I suspect that air-launching a rocket would probably save less, as the structure has to be strengthened to resist sagging under gravity (whereas a spaceplane like HOTOL is already strengthened).
The amount you gain is heavily dependent on the excess thrust of the engines, i.e. the acceleration or gee force they impart after separation. For a high-gee, solid-fuel system like Pegasus it might actually be bigger than its vertical-launch equivalent.
« Last Edit: September 05, 2018, 12:56:59 pm by steelpillow »
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Offline blackstar

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Re: Stratolaunch
« Reply #189 on: September 06, 2018, 03:48:37 pm »
Not one of your statements is backed by data.

Nor are any of yours. Eugene Sanger, B.Ae, Pegasus, Scaled Composites, Virgin Galactic and Stratolaunch have all thought your views to be rubbish. I am inclined to agree with them.

There's an old saying that on the internet, nobody knows you're a dog. But you have to be careful, because on the internet, you could actually be arguing with somebody who flies rockets for a living...

Offline blackstar

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Re: Stratolaunch
« Reply #190 on: September 06, 2018, 04:03:09 pm »
1-Air launch doesn’t seem to provide an obvious advantage but you have 2 new business startups pursuing this architecture with serious money. 

2-There are also examples of air launched ballistic missiles and targets.

3-Something must be advantageous about this approach and I would be very surprised if trade studies vs ground launch hadn’t been analyzed before money was committed.

1-Even in the recent past there were many more such proposals, but they haven't gotten funding. So two startups with funding doesn't prove the success of this model. Let's see if they are launching customers ten years from now.

2-There are no operational air-launched ballistic missiles. But that's a different set of issues. Ballistic missiles don't have to make money, they just have to work. And air-launching a ballistic missile has some operational drawbacks. In order to reduce vulnerability, you have to keep the plane in the air a lot, and that's expensive. These operating schemes have just never worked out, but they've been evaluated numerous times.

3-Well, in the case of Stratolaunch it appears to be primarily an ego-driven project. A rich guy wanted the biggest airplane in the world and he wanted it to launch rockets. It's just like owning a really large yacht. The fact that they've gotten this far without a rocket is an indication of how much the circle doesn't close on this approach.

Virgin is a different case, and in some ways a more logical one. They're using a surplus 747 that they were going to write off anyway. Virgin already has maintenance and other logistics infrastructure to maintain this plane, so it's not like they have to pay somebody else to do it, They can also keep some of their related costs low, like having the pilots fly regular revenue flights until needed for a launch mission. That helps to keep the cost of the airplane low. Now is it going to be low enough to make them profitable (all other things considered)? We don't know. The carrying cost for the plane (meaning how much they are going to have to spend every year just to keep the plane flying) is still going to cost some serious cash. And they're going to have to be innovative on the rocket and payload processing side. I'd like to see them succeed, because it's a cool idea. But we should all be honest and admit that air-launch is very much a niche and there's no reason to believe that any of these efforts will succeed.

Offline TomcatViP

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Re: Stratolaunch
« Reply #191 on: September 07, 2018, 03:41:56 am »
Don't forget that their aircraft is certified so they can fly it anywhere, anytime  (but without payload) to meet customer launch site expectations easily. So basically they will have a global business soon or latter.

The drawbacks is that as a civilian airliner,  maintenance will prove to be higher with a lot of systems non-relevant for the mission. Stratolaunch have only a modern tailored composite airframe to sustain which certainly would prove to cost less per pound in orbit.     

Offline Mark Nankivil

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Re: Stratolaunch
« Reply #192 on: September 07, 2018, 07:01:45 am »
Don't forget there are costs for ground based operations - whether you own the launch site and infrastructure or lease/rent it.  All part of the cost analysis but the ground option is not free. 

Enjoy the Day!  Mark

Offline blackstar

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Re: Stratolaunch
« Reply #193 on: September 07, 2018, 11:00:15 am »
Don't forget that their aircraft is certified so they can fly it anywhere, anytime  (but without payload) to meet customer launch site expectations easily. So basically they will have a global business soon or latter.


I doubt that they will be able to take the rocket to any foreign country they want for launching purposes. The rocket is on the munitions list.

Offline Byeman

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Re: Stratolaunch
« Reply #194 on: September 07, 2018, 11:32:24 am »
Not one of your statements is backed by data.

Nor are any of yours. Eugene Sanger, B.Ae, Pegasus, Scaled Composites, Virgin Galactic and Stratolaunch have all thought your views to be rubbish. I am inclined to agree with them.

Another statement lacking data for support.
And just because they are doing something doesn't mean they are right or never supports your claim.
Sanger built anything.  B.Ae hasn't done anything air launched.  Pegasus is the most expensive per lb of payload for any launch vehicle. Scaled Composites isn't producing orbital vehicle. Stratolaunch is a plane looking for a mission.

BTW, my statements are backed by data.  They just point out where yours lacked data.

Also, your logic is flawed.  Just because somebody comes up with a paper concept does not mean it is good,  viable or workable.  There are thousands of paper concepts like Sea Dragon, ROMBUS, Orion, etc. 

« Last Edit: September 07, 2018, 11:43:25 am by Byeman »

Offline Byeman

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Re: Stratolaunch
« Reply #195 on: September 07, 2018, 11:45:29 am »

Nor are any of yours. Eugene Sanger, B.Ae, Pegasus, Scaled Composites, Virgin Galactic and Stratolaunch have all thought your views to be rubbish. I am inclined to agree with them.

So you also like to beat dead horses too? 


Actually, anything I said would not be "rubbish" to them.  They would understand what I said and would agree.

Offline XP67_Moonbat

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Re: Stratolaunch
« Reply #196 on: September 07, 2018, 02:31:46 pm »
I'm gonna have to go with Byeman on this... Beating a dead horse here.

StratoLaunch at sunrise, for your trouble.
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Offline Archibald

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Re: Stratolaunch
« Reply #197 on: September 07, 2018, 11:46:10 pm »
Not one of your statements is backed by data.

Nor are any of yours. Eugene Sanger, B.Ae, Pegasus, Scaled Composites, Virgin Galactic and Stratolaunch have all thought your views to be rubbish. I am inclined to agree with them.

There's an old saying that on the internet, nobody knows you're a dog. But you have to be careful, because on the internet, you could actually be arguing with somebody who flies rockets for a living...

ROTFLMAO, as they say.
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Offline ADVANCEDBOY

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Re: Stratolaunch
« Reply #198 on: September 19, 2018, 09:03:29 am »
Does anyone know when is the first flight due? They promised to take it airborne by the end of the summer. The summer is over. The bird is still taxiing.
P.S. I hope it doesn`t break in half. For  such  long fuselages to be joined only by a single skinny wing , I  am concerned.  Especially when dealing with torsional forces. The rear wing and the rudder are very far away from the central  wing and if rudders or ailerons are used to compensate air flows on one side , it will exert huge loads on the central  wing  where it is joined to each of the fuselages. Just a wild guess.
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Offline Flyaway

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Re: Stratolaunch
« Reply #199 on: September 20, 2018, 03:49:49 am »