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Author Topic: DARPA Experimental Spaceplane (XS-1)  (Read 24847 times)

Offline blackstar

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Re: DARPA Experimental Spaceplane (XS-1)
« Reply #15 on: March 29, 2014, 05:11:43 am »
ALASA

Offline bobbymike

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Re: DARPA Experimental Spaceplane (XS-1)
« Reply #16 on: March 29, 2014, 08:35:57 am »
ALASA

Not to jump topics but could ALASA be a strike weapon or a tail chase ABM
"The real man smiles in trouble, gathers strength from distress, and grows brave by reflection." - Thomas Paine

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Offline DSE

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Re: DARPA Experimental Spaceplane (XS-1)
« Reply #17 on: March 31, 2014, 11:23:57 am »
ALASA


Boeing: Boeing wins contract to design DARPA Airborne Satellite Launch Vehicle
Quote
Boeing’s design takes the concept one step further and shifts traditional thinking when it comes to today’s launch vehicles.
 “As these stages are jettisoned (or dropped), the fuel tank and engines are just thrown away. We developed a cost-effective design by moving the engines forward on the launch vehicle. With our design, the first and second stages are powered by the same engines, reducing weight and complexity,” explained Steve Johnston, director, Advanced Space Exploration.

Having a hard time wrapping my head around how this might be accomplished, but then again it is Monday.
Also, isn't the F-15 the first stage?
« Last Edit: March 31, 2014, 11:46:34 am by DSE »

Offline blackstar

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Re: DARPA Experimental Spaceplane (XS-1)
« Reply #18 on: March 31, 2014, 12:38:52 pm »
ALASA

Not to jump topics but could ALASA be a strike weapon or a tail chase ABM

Why would it be either of those things? If you want a strike weapon, you design a strike weapon. No need to go through all this trouble to say that you're designing a small satellite launcher and then do something else with it.

And under what scenario would a "tail chase" ABM work? If you're behind the missile you want to shoot down, then you're over the bad guy's territory. Why would you be there? And if you were there, why wouldn't you just be shooting at the missile on the ground?

There's a lot of interest in really small satellites lately. They are usually launched in multiples atop bigger rockets, almost always as ride-along secondary payloads. That makes their launch relatively cheap, but it also puts the secondary at the mercy of the main payload. So for awhile now people have been talking about developing cheap ways to launch small satellites one at a time. ALASA is one effort to do that. We can have our doubts, because for starters an F-15 is not a cheap aircraft to operate. And if you only have one, you have to spread out your cost across all your launches. Thus, if it only launches once a month, you have to charge the entire month's cost to that launch. (And if it only launches once a year, you charge the entire year's cost.)

We'll see if they can make it work. Remember that DARPA is often about trying stuff to see if the technology can work, but it does not have to turn into something that is useful in the end. People remember DARPA's successes, but are often unaware that they fail a lot. DARPA fails a lot at what it tries to do. (Let's repeat that: DARPA fails a lot at what it tries to do.)
« Last Edit: April 01, 2014, 07:37:00 am by blackstar »

Offline sferrin

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Re: DARPA Experimental Spaceplane (XS-1)
« Reply #19 on: March 31, 2014, 12:54:48 pm »
If they never failed I'd be worried.  It would mean they're not trying hard enough.  ;D
"DARPA Hard"  It ain't what it use to be.

Offline bobbymike

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Re: DARPA Experimental Spaceplane (XS-1)
« Reply #20 on: March 31, 2014, 02:06:25 pm »
When I say 'tail chase' I just mean boost phase interception with a missile I believe the concept has been studied in various configurations with a very fast burn missile. I have just read that referred to as chasing a missiles tail, sorry if I was unclear in my post.
 
..............The BPI Phase I ACTD evaluated the affordability and assessed the operational utility and mission effectiveness of BPI engagements. The BPI ACTD technical approach employed a high speed tactical missile with a kinetic kill vehicle carried on an airbreathing platform such as the F-14 or F-15. The missile was capable of velocities in excess of 3 km/s and a range of 120 km, and was designed to be a precursor to an objective system with a 5.5 km/s velocity and a 250 km range. On-board and off-board sensors were used to detect, track, and provide in-flight updates. The BPI Phase I was completed in fourth quarter FY95............
 
http://scienceandglobalsecurity.org/archive/sgs12wilkening.pdf
 
 
As for weaponization something that could put a 100kg payload in orbit can put a 100kg warhead 'next' to something in orbit or if it in going from air to ground probably a larger warhead for A2G.
« Last Edit: March 31, 2014, 02:15:55 pm by bobbymike »
"The real man smiles in trouble, gathers strength from distress, and grows brave by reflection." - Thomas Paine

"On what principle is it that with nothing but improvement behind us, we are to expect nothing but deterioration before us?" - Lord Macaulay

Offline blackstar

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Re: DARPA Experimental Spaceplane (XS-1)
« Reply #21 on: March 31, 2014, 02:20:04 pm »
When I say 'tail chase' I just mean boost phase interception with a missile I believe the concept has been studied in various configurations with a very fast burn missile. I have just read that referred to as chasing a missiles tail, sorry if I was unclear in my post.
 
..............The BPI Phase I ACTD evaluated the affordability and assessed the operational utility and mission effectiveness of BPI engagements. The BPI ACTD technical approach employed a high speed tactical missile with a kinetic kill vehicle carried on an airbreathing platform such as the F-14 or F-15. The missile was capable of velocities in excess of 3 km/s and a range of 120 km, and was designed to be a precursor to an objective system with a 5.5 km/s velocity and a 250 km range. On-board and off-board sensors were used to detect, track, and provide in-flight updates. The BPI Phase I was completed in fourth quarter FY95............
 
http://scienceandglobalsecurity.org/archive/sgs12wilkening.pdf
 
 
As for weaponization something that could put a 100kg payload in orbit can put a 100kg warhead 'next' to something in orbit or if it in going from air to ground probably a larger warhead for A2G.

And if you're going to do either of those things, why not just do those things? Why do this instead?

There's lots of problems/issues with the things you mention. BPI, for instance, requires that you be relatively close to the launch site. It also requires really good tracking. There has been some discussion of doing that with F-15 type launches (the Israelis were interested a few years ago). Problem is that you'd have to put a lot of interceptors up. And you'd have to have good intel and tracking. Tough thing to do.

USAF is not in favor of kinetic kill ASATs. They don't want to create a lot of debris that might end up destroying their own satellites.

So, no. This is not for doing that. This is for doing what they say it is for.

Offline bobbymike

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Re: DARPA Experimental Spaceplane (XS-1)
« Reply #22 on: March 31, 2014, 02:59:59 pm »
When I say 'tail chase' I just mean boost phase interception with a missile I believe the concept has been studied in various configurations with a very fast burn missile. I have just read that referred to as chasing a missiles tail, sorry if I was unclear in my post.
 
..............The BPI Phase I ACTD evaluated the affordability and assessed the operational utility and mission effectiveness of BPI engagements. The BPI ACTD technical approach employed a high speed tactical missile with a kinetic kill vehicle carried on an airbreathing platform such as the F-14 or F-15. The missile was capable of velocities in excess of 3 km/s and a range of 120 km, and was designed to be a precursor to an objective system with a 5.5 km/s velocity and a 250 km range. On-board and off-board sensors were used to detect, track, and provide in-flight updates. The BPI Phase I was completed in fourth quarter FY95............
 
http://scienceandglobalsecurity.org/archive/sgs12wilkening.pdf
 
 
As for weaponization something that could put a 100kg payload in orbit can put a 100kg warhead 'next' to something in orbit or if it in going from air to ground probably a larger warhead for A2G.

And if you're going to do either of those things, why not just do those things? Why do this instead?

There's lots of problems/issues with the things you mention. BPI, for instance, requires that you be relatively close to the launch site. It also requires really good tracking. There has been some discussion of doing that with F-15 type launches (the Israelis were interested a few years ago). Problem is that you'd have to put a lot of interceptors up. And you'd have to have good intel and tracking. Tough thing to do.

USAF is not in favor of kinetic kill ASATs. They don't want to create a lot of debris that might end up destroying their own satellites.

So, no. This is not for doing that. This is for doing what they say it is for.
Sorry did I imply this is what the program was for or simply ask if the booster/payload combo could be used for those alternate purposes? Like using an ATACMS for the X-51 test. I'm sure when the first ATACMS was shown at ground launch if someone would have asked, 'Hey can you put one of those on a B-52 external pylon for hypersonics research"? Would have gotten the same response you just gave me.
"The real man smiles in trouble, gathers strength from distress, and grows brave by reflection." - Thomas Paine

"On what principle is it that with nothing but improvement behind us, we are to expect nothing but deterioration before us?" - Lord Macaulay

Offline blackstar

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Re: DARPA Experimental Spaceplane (XS-1)
« Reply #23 on: March 31, 2014, 04:01:32 pm »

Sorry did I imply this is what the program was for or simply ask if the booster/payload combo could be used for those alternate purposes?

That rocket could also be used to cook steaks. It's not ideal for that, mind you, but fire is fire, right?

Boost phase intercept requires really high acceleration to go catch a missile from behind. Satellite launchers tend to not have really high acceleration.

Offline bobbymike

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Re: DARPA Experimental Spaceplane (XS-1)
« Reply #24 on: March 31, 2014, 04:46:38 pm »

Sorry did I imply this is what the program was for or simply ask if the booster/payload combo could be used for those alternate purposes?

That rocket could also be used to cook steaks. It's not ideal for that, mind you, but fire is fire, right?

Boost phase intercept requires really high acceleration to go catch a missile from behind. Satellite launchers tend to not have really high acceleration.

Mmmm - rocket steaks
"The real man smiles in trouble, gathers strength from distress, and grows brave by reflection." - Thomas Paine

"On what principle is it that with nothing but improvement behind us, we are to expect nothing but deterioration before us?" - Lord Macaulay

Offline blackstar

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Re: DARPA Experimental Spaceplane (XS-1)
« Reply #25 on: April 01, 2014, 07:36:33 am »
Scroll back up and look at the ALASA image.

Notice that the rocket appears to have its engine nozzles near the top. Interesting, no?

Offline bobbymike

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Re: DARPA Experimental Spaceplane (XS-1)
« Reply #26 on: April 01, 2014, 03:45:10 pm »
Scroll back up and look at the ALASA image.

Notice that the rocket appears to have its engine nozzles near the top. Interesting, no?

Yes very interesting a nosecone divert system prior to payload release of mini-sat?
"The real man smiles in trouble, gathers strength from distress, and grows brave by reflection." - Thomas Paine

"On what principle is it that with nothing but improvement behind us, we are to expect nothing but deterioration before us?" - Lord Macaulay

Offline blackstar

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Re: DARPA Experimental Spaceplane (XS-1)
« Reply #27 on: April 01, 2014, 05:05:41 pm »
Scroll back up and look at the ALASA image.

Notice that the rocket appears to have its engine nozzles near the top. Interesting, no?

Yes very interesting a nosecone divert system prior to payload release of mini-sat?

Those are the rocket engine nozzles.

Offline TomS

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Re: DARPA Experimental Spaceplane (XS-1)
« Reply #28 on: April 01, 2014, 06:59:17 pm »
So it's got a tractor configuration, with the fuel tanks for the first stage below the rocket engines.  The first stage pumps fuel up the stack to the engines, then drops the tank when it's empty.

Offline blackstar

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Re: DARPA Experimental Spaceplane (XS-1)
« Reply #29 on: April 02, 2014, 08:10:39 am »
So it's got a tractor configuration, with the fuel tanks for the first stage below the rocket engines.  The first stage pumps fuel up the stack to the engines, then drops the tank when it's empty.

Yeah, and the question is why? What advantage is this configuration? One guess is that they have a two-stage configuration, but keep the engines, only dropping a tank.