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Author Topic: Stratolaunch  (Read 68647 times)

Offline martinbayer

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Re: Stratolaunch
« Reply #330 on: February 09, 2019, 01:59:18 am »
"are you perhaps just "winging" it in this thread?"
Given that the Roc in particular, never mind carrier/orbiter composite aircraft in general, still has to fly at all, I think we are all heavily winging it here.

May I ask that we keep this thread civil?

Although the overarching topic of this thread is Stratolaunch in general, keeping in mind that the Mriya has successfully flown with an airlifted total payload of over 250 metric tons, and that this plane was envisioned as the carrier aircraft for the Interim Hotol concept that I have brought up before in this thread, to me the successful first flight of the Roc really isn't the critical pacing item in this particular line of discussion regarding a reusable subsonically air launched orbiter.
« Last Edit: February 09, 2019, 11:21:21 pm by martinbayer »
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Offline Byeman

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Re: Stratolaunch
« Reply #331 on: February 10, 2019, 05:53:51 am »

I see no reason why a winged spaceplane might not have benefited from advantages in terms of design, ops and comparatively cheap labor as well, if Paul Allen were still alive.

There are many reasons why.  First major one is that Paul Allen had nothing to do with the design or engineering, so his presence is immaterial.  Two, he is not Elon Musk.  Three, the company is not vertically integrated.  Do I need to go on.

Offline Byeman

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Re: Stratolaunch
« Reply #332 on: February 10, 2019, 06:00:18 am »

 it really isn't a current consideration for most commercial and civil customers, which is in my understanding the market segment Stratolaunch was mainly targeting in the long run.

Yes, it is. They also wouldn't like the longer prep time before launch.

And, there are other drawbacks.   Example, Falcon 9 can only delay 15 or minutes once the sub cooled propellants are on board.  Not really useful for vehicle built for loitering.

Offline Byeman

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Re: Stratolaunch
« Reply #333 on: February 10, 2019, 06:01:48 am »
Goddam boiloff, forgot that one...

Boiloff losses could potentially be avoided by using subcooled propellants, see for example https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20180000059.pdf

And no again.   That is for an upperstage with super insulation. 

Offline martinbayer

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Re: Stratolaunch
« Reply #334 on: February 10, 2019, 08:24:20 am »

I see no reason why a winged spaceplane might not have benefited from advantages in terms of design, ops and comparatively cheap labor as well, if Paul Allen were still alive.

There are many reasons why.  First major one is that Paul Allen had nothing to do with the design or engineering, so his presence is immaterial.  Two, he is not Elon Musk.  Three, the company is not vertically integrated.  Do I need to go on.

Allen was quite obviously the founder of and driving force behind Stratolaunch and was willing to invest substantial amounts of funding into the project, which made his presence *highly* material for the continuation of the associated efforts, as is evident by the cancellation of launch vehicle related work not long after his death, since whoever is now in charge evidently does not share his vision.
« Last Edit: February 10, 2019, 11:06:19 pm by martinbayer »
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Offline martinbayer

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Re: Stratolaunch
« Reply #335 on: February 10, 2019, 08:33:22 am »

 it really isn't a current consideration for most commercial and civil customers, which is in my understanding the market segment Stratolaunch was mainly targeting in the long run.

Yes, it is. They also wouldn't like the longer prep time before launch.

And, there are other drawbacks.   Example, Falcon 9 can only delay 15 or minutes once the sub cooled propellants are on board.  Not really useful for vehicle built for loitering.

Quote from https://spacenews.com/stratolaunch-charts-course-tough-market/:

"Commercial communications satellites are among the payloads Stratolaunch is gunning for.

“There is a thriving communications satellite market for small- to medium-class communications satellites,” Stratolaunch board member and former NASA Administrator Mike Griffin said at the company’s Dec. 13 press conference. “This would make a very effective launcher for such things.”

Griffin also said that Stratolaunch had its eye on a government market that produces “unmanned scientific satellites of one kind or another … at least half a dozen or so a year.” Most of these, he said, would be NASA payloads; a few would be military."

Quote from https://www.nbcnews.com/mach/science/billionaire-readies-world-s-largest-plane-launch-rockets-space-ncna909251:

"Eventually, Stratolaunch Systems plans to develop a “heavy” MLV variant using two half-length MLVs as side boosters. That rocket would handle payloads of up to 13,000 pounds.

Those capacities will place the rockets in an untapped region of the burgeoning commercial spaceflight market."

While the first quote mentions "a few" unmanned scientific satellites that would be military (and as scientific payloads would in all likelihood not require launch on demand), both sources agree on the emphasis on the commercial satellite market, at least in the near to medium term. Please provide *any* concrete sources (with verifiable online links) that contain any evidence of current commercial satellite launch customers requiring quick reaction and loiter capabilities for their payload deployments. Note also that while the references above pertain to expendable Stratolaunch vehicles, a reusable spaceplane would have the potential to address additional other and new market segments, including for example crewed orbital flights using a passenger module in the payload bay, that would also not realistically be expected to require quick reaction times or subsonic loiter.
« Last Edit: February 11, 2019, 12:19:30 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 Archibald

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Re: Stratolaunch
« Reply #336 on: February 10, 2019, 08:38:01 am »
Well I didn't wanted to create such a stir. Nor being pedantic in any way. I just wanted to assess what amount of payload could be send to the minimum-LEO by an expendable-LOX/LH2-rocket-stage-dropped-from-Roc. So 18 mt or a bit less.
The goal being to try and extrapolate a rocketplane out of this.

https://cdn.vox-cdn.com/thumbor/UdCl6W6n1EvTWLi77JRvrm_1apk=/0x0:1920x1080/1200x800/filters:focal(826x287:1132x593)/cdn.vox-cdn.com/uploads/chorus_image/image/60957099/Life_Cycle_2a__1_.0.jpg

Rocketplane mean (the way I see it, no idea if Black Ice was to be like this, I'm no Paul Allen)
a) no drop tank
b) no booster stage
c) in short, kind of Venture Star (not X-33)
d) dropped from Roc  that is
e) no more than 250 mt 

Build the rocketplane below out of the expendable rocket stage 18 mt of payload. If the wings +twin tail + undercarriage + payload weights more than 18 mt - GAME OVER. Zero payload, and no orbit.

http://aviationweek.com/site-files/aviationweek.com/files/gallery_images/Stratolaunch%20LV%20B_0.jpg
« Last Edit: February 10, 2019, 08:43:18 am by Archibald »
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Offline martinbayer

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Re: Stratolaunch
« Reply #337 on: February 10, 2019, 08:45:56 am »
Goddam boiloff, forgot that one...

Boiloff losses could potentially be avoided by using subcooled propellants, see for example https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20180000059.pdf

And no again.   That is for an upperstage with super insulation.

And it is also for a stage that is designed to store both cryogenic propellant components without any boiloff losses for *months*, rather than for just *hours* in case of a air launched orbital vehicle. This mission duration reduction by a factor of almost three orders of magnitude can reasonably be expected to more than compensate for any differences in insulation approaches and environmental conditions.
« Last Edit: February 11, 2019, 11:50:11 am 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 Byeman

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Re: Stratolaunch
« Reply #338 on: February 12, 2019, 11:29:54 am »
Goddam boiloff, forgot that one...

Boiloff losses could potentially be avoided by using subcooled propellants, see for example https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20180000059.pdf

And no again.   That is for an upperstage with super insulation.

And it is also for a stage that is designed to store both cryogenic propellant components without any boiloff losses for *months*, rather than for just *hours* in case of a air launched orbital vehicle. This mission duration reduction by a factor of almost three orders of magnitude can reasonably be expected to more than compensate for any differences in insulation approaches and environmental conditions.

Still not applicable to an atmospheric much less an air launched vehicle.  The insulation is for a vacuum.
« Last Edit: February 12, 2019, 11:35:20 am by Byeman »

Offline Byeman

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Re: Stratolaunch
« Reply #339 on: February 12, 2019, 11:34:38 am »
any evidence of current commercial satellite launch customers requiring quick reaction and loiter capabilities for their payload deployments.

I never said that.  The loiter time I was referring to is the time from GSE disconnect with the time to climb and getting to the launch box.  That is on the order of an hour.  Way outside of time of holding sub cooled propellants, especially LH2.

Offline Byeman

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Re: Stratolaunch
« Reply #340 on: February 12, 2019, 11:38:23 am »


Griffin also said that Stratolaunch had its eye on a government market that produces “unmanned scientific satellites of one kind or another … at least half a dozen or so a year.” Most of these, he said, would be NASA payloads; a few would be military."

Quote from https://www.nbcnews.com/mach/science/billionaire-readies-world-s-largest-plane-launch-rockets-space-ncna909251:

"Eventually, Stratolaunch Systems plans to develop a “heavy” MLV variant using two half-length MLVs as side boosters. That rocket would handle payloads of up to 13,000 pounds.

Those capacities will place the rockets in an untapped region of the burgeoning commercial spaceflight market."

While the first quote mentions "a few" unmanned scientific satellites that would be military (and as scientific payloads would in all likelihood not require launch on demand), both sources agree on the emphasis on the commercial satellite market, at least in the near to medium term. Please provide *any* concrete sources (with verifiable online links) that contain any evidence of current commercial satellite launch customers requiring quick reaction and loiter capabilities for their payload deployments. Note also that while the references above pertain to expendable Stratolaunch vehicles, a reusable spaceplane would have the potential to address additional other and new market segments, including for example crewed orbital flights using a passenger module in the payload bay, that would also not realistically be expected to require quick reaction times or subsonic loiter.

Your "sources" are market pitches or fluff and not relevant.

Griffin does not speak for NASA.  There would be little benefit to NASA to use this for scientific missions.  The only reason NASA used Pegasus was for cost and not the air launch capability


Offline martinbayer

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Re: Stratolaunch
« Reply #341 on: February 12, 2019, 11:50:59 am »
Goddam boiloff, forgot that one...

Boiloff losses could potentially be avoided by using subcooled propellants, see for example https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20180000059.pdf

And no again.   That is for an upperstage with super insulation.

And it is also for a stage that is designed to store both cryogenic propellant components without any boiloff losses for *months*, rather than for just *hours* in case of a air launched orbital vehicle. This mission duration reduction by a factor of almost three orders of magnitude can reasonably be expected to more than compensate for any differences in insulation approaches and environmental conditions.

Still not applicable to an atmospheric much less an air launched vehicle.  The insulation is for a vacuum.

The focus of my post was on the subcooled propellants - that's why I *specifically and explicitly* stated that the "mission duration reduction by a factor of almost three orders of magnitude can reasonably be expected to more than compensate for any *differences in insulation approaches and environmental conditions*" (emphasis mine). For atmospheric applications, *other* reusable cryogenic insulation concepts are applicable, for example as discussed in https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20050217094.pdf - why are you so dense (pun intended?).
« Last Edit: February 13, 2019, 11:57:28 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 martinbayer

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Re: Stratolaunch
« Reply #342 on: February 12, 2019, 12:00:21 pm »
any evidence of current commercial satellite launch customers requiring quick reaction and loiter capabilities for their payload deployments.

I never said that.  The loiter time I was referring to is the time from GSE disconnect with the time to climb and getting to the launch box.  That is on the order of an hour.  Way outside of time of holding sub cooled propellants, especially LH2.

First of all, that is definitely *not* loiter, which for example per Wikipedia is defined as "cruising for a certain amount of time *over a small region*" (my emphasis) - you apparently (?) really meant the transit flight time from takeoff point to launch point, which would obviously be kept as short as possible, both in terms of distance over ground as well as time, rather than flying around in circles. Once again, the potential cryogenic propellant holding time also depends on the chosen insulation concept, which the Falcon 9 that you tried to use as a counter example is utterly and completely *lacking*, see for example the discussion in https://elib.dlr.de/120200/1/SP2018_478_PA.pdf.
« Last Edit: February 13, 2019, 11:53:07 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 martinbayer

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Re: Stratolaunch
« Reply #343 on: February 12, 2019, 12:07:06 pm »


Griffin also said that Stratolaunch had its eye on a government market that produces “unmanned scientific satellites of one kind or another … at least half a dozen or so a year.” Most of these, he said, would be NASA payloads; a few would be military."

Quote from https://www.nbcnews.com/mach/science/billionaire-readies-world-s-largest-plane-launch-rockets-space-ncna909251:

"Eventually, Stratolaunch Systems plans to develop a “heavy” MLV variant using two half-length MLVs as side boosters. That rocket would handle payloads of up to 13,000 pounds.

Those capacities will place the rockets in an untapped region of the burgeoning commercial spaceflight market."

While the first quote mentions "a few" unmanned scientific satellites that would be military (and as scientific payloads would in all likelihood not require launch on demand), both sources agree on the emphasis on the commercial satellite market, at least in the near to medium term. Please provide *any* concrete sources (with verifiable online links) that contain any evidence of current commercial satellite launch customers requiring quick reaction and loiter capabilities for their payload deployments. Note also that while the references above pertain to expendable Stratolaunch vehicles, a reusable spaceplane would have the potential to address additional other and new market segments, including for example crewed orbital flights using a passenger module in the payload bay, that would also not realistically be expected to require quick reaction times or subsonic loiter.

Your "sources" are market pitches or fluff and not relevant.

Griffin does not speak for NASA.  There would be little benefit to NASA to use this for scientific missions.  The only reason NASA used Pegasus was for cost and not the air launch capability

So you simply consider news reports that don't agree with your opinions as "market pitches or fluff and not relevant" - hmm, why does that remind me of online cries of "fake news"? By all means, if you have objectively documented sources that contradict the information provided under the links I proffered, please feel free completely to share them with us! Even if he does no longer officially speak for NASA, as a former NASA administrator who is now the Under Secretary of Defense for Research and Engineering, I consider Mike Griffin's views on the topic in question as *extremely* well informed. You also still have provided exactly zero evidence that backs up your claim that commercial satellite customers care about quick reaction launches, or that the Roc capability sizing was completely independent of the air launched orbiter studies I quoted previously.
« Last Edit: February 13, 2019, 11:50:45 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 Antonio

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Re: Stratolaunch
« Reply #344 on: February 12, 2019, 01:22:31 pm »
Dear sirs, please avoid going personal and try to post for the general interest of the forum.