Author Topic: DARPA Experimental Spaceplane 1 (XS-1) Program  (Read 419527 times)

Offline Robotbeat

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #400 on: 07/19/2014 10:03 pm »
You can increase the performance of a rubber band system by using a tapered band and heating the band (below the point where it breaks down, of course). It's possible to get a rubber band to exceed Mach 1 (though very difficult to do so).

Not worth it, of course. :) But fun.
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Offline yg1968

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Offline john smith 19

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #402 on: 07/21/2014 08:52 am »
You can increase the performance of a rubber band system by using a tapered band and heating the band (below the point where it breaks down, of course). It's possible to get a rubber band to exceed Mach 1 (though very difficult to do so).

Not worth it, of course. :) But fun.
Now that I did not expect...

Definitely one for the scrapbook of surprising physical phenomena.

I admit I've a fondness for cheap launch assist systems. I'd not really considered them before.

All of which is by way of observing that the end goal should be much more important than how the various entrants get there, since it's the only one that matters.
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Robotbeat

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #403 on: 07/22/2014 04:10 am »
You can increase the performance of a rubber band system by using a tapered band and heating the band (below the point where it breaks down, of course). It's possible to get a rubber band to exceed Mach 1 (though very difficult to do so).

Not worth it, of course. :) But fun.
Now that I did not expect...

Definitely one for the scrapbook of surprising physical phenomena.

I admit I've a fondness for cheap launch assist systems. I'd not really considered them before.

All of which is by way of observing that the end goal should be much more important than how the various entrants get there, since it's the only one that matters.
I suppose I should clarify... I believe it is /possible/ to break Mach 1 (with part of the band) with an extremely tapered band heated to its disintegration temperature, though I have not done it myself (with an extreme enough taper, I don't see why it couldn't technically be done, especially with some clever restraint mechanism). There have been some reports of 890 fps slingshot records, though they may be anomalous. 500fps projectiles with unheated bands is not unheard of.

Anyway, sorry. Off-topic and pointless.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline john smith 19

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #404 on: 07/22/2014 06:58 pm »
I suppose I should clarify... I believe it is /possible/ to break Mach 1 (with part of the band) with an extremely tapered band heated to its disintegration temperature, though I have not done it myself (with an extreme enough taper, I don't see why it couldn't technically be done, especially with some clever restraint mechanism). There have been some reports of 890 fps slingshot records, though they may be anomalous. 500fps projectiles with unheated bands is not unheard of.
Hmm. Definitely a corner case then.  :(
Quote
Anyway, sorry. Off-topic and pointless.
Agreed. Still one for the scrapbook.  :)

Personally I am looking forward to seeing how the various entrants will handle the heat problem. One of the things that wrong footed the entrants to the X15 competition was that they did not realizes the USAF wanted an aircraft that could soak at the full Mach speed, as part of the experimental regime.

I don't think DARPA is calling for that capability, although M10 is well above any reusable vehicles operating range. X15 tried spray on ablator but that was a royal PITA to apply and strip off.  :(
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Star One

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #405 on: 07/22/2014 07:42 pm »

I suppose I should clarify... I believe it is /possible/ to break Mach 1 (with part of the band) with an extremely tapered band heated to its disintegration temperature, though I have not done it myself (with an extreme enough taper, I don't see why it couldn't technically be done, especially with some clever restraint mechanism). There have been some reports of 890 fps slingshot records, though they may be anomalous. 500fps projectiles with unheated bands is not unheard of.
Hmm. Definitely a corner case then.  :(
Quote
Anyway, sorry. Off-topic and pointless.
Agreed. Still one for the scrapbook.  :)

Personally I am looking forward to seeing how the various entrants will handle the heat problem. One of the things that wrong footed the entrants to the X15 competition was that they did not realizes the USAF wanted an aircraft that could soak at the full Mach speed, as part of the experimental regime.

I don't think DARPA is calling for that capability, although M10 is well above any reusable vehicles operating range. X15 tried spray on ablator but that was a royal PITA to apply and strip off.  :(

Talking of the build materials guess you missed this that I already posted up thread.

http://www.engadget.com/2014/07/11/darpa-materials-program/

Offline a_langwich

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #406 on: 07/23/2014 07:15 am »
Interesting point.  So reusable VTVL 1st stage and expendable 2nd?

Yeah. All the XS-1 contracts are focused on TSTO designs wiht reusable first stages with expendable 2nd stages, and I'm 95% sure Masten is going for a VTVL first stage for this effort. I mean, they could surprise us all, but I doubt it.

My impression as a way outsider (PeanutGallery, I'm with you!) is that neither XCOR nor Masten have considerable expertise in aerodynamics and high speed (multi-Mach) flight structures.  So, it would seem logical to me that they would focus on the vertical rocketry, which has lower demands than the other alternatives in this area.

If XCOR had extensive suborbital flight experience, that might be different (though as you suggest it might not make any difference as long as Masten was the lead), but they don't and airframe and structures seem to be the holdup. 

Quote
That's what I'm hoping. My instinct is it might be the combination of payload size and speed that makes it impossible to close.

That said would it be DARPA if the requirements weren't almost impossible to be met?  :)

Hopefully they're open to creative interpretations of their requirements. For instance if the Mach 10 requirement is only on one flight, and isn't the staging velocity for a 3-5klb to LEO upper stage but just the max speed a first stage can get to with a small or non-existant upper stage, it might work. Especially if there's no requirement for the vehicle to hit Mach 10 inside the atmosphere--for instance if you could get up to Mach 10, release a small payload, then do a boostback that slows you to something reasonable before you hit the thick part of the atmosphere, that might make it more realistic as well. We shall see.


I wonder, if you were looking to launch experiments like the X-43, even scaled up, how hard a requirement would that be?  I can't imagine you could do that (a relative flat trajectory up to Mach 10) and return to the launch site.  Not even sure how long the structure would remain glowingly hot, which would seem to me to preclude refueling for another flight.  :)  But I suppose you could make it the last flight of the ten, or just make the next flight a very short-hop ferry back toward launch site.  Or, in the spirit of your "creative interpretations," wait 23 hours for cooldown, then a short vertical flight nowhere, then the next day fly back toward the launch site. 

In my opinion, these are super-stretch goals, and the truth is if any of the competitors could meet the cost to orbit and a few day turnaround, I think all else would be forgiven.  By some customer, at least, if not DARPA.  If they could meet the payload to orbit and the turnaround time, and get $/LEO-lb in a currently competitive range, they probably have a future.  I don't see a whole lot of love, in the market or even at USAF, for the Mach 10 requirement, so my guess is it's the Requirement Most Likely To Be Creatively Interpreted.  Although the ten flights in ten days--for that matter, any of the rest!--might inspire some creative interpretation out of sheer desperation in trying to meet it.  "Can we use Lunar days?"

I'm excited to see what these companies conjure up.  The true test, IMO, of the program will be how many future Wikipedia entries have something like "the idea for this product sprang from work the company did for DARPA during the XS-1 program..."

Offline john smith 19

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #407 on: 07/23/2014 09:47 am »
Talking of the build materials guess you missed this that I already posted up thread.

http://www.engadget.com/2014/07/11/darpa-materials-program/
No I did see it but it's simply irrelevant in this time frame.

Space Ship 1 proved that with creative design and strategic placement of ablator you could build a vehicle that would hit M3 out of conventional composites.

Personally my vote for the best TPS that never was is Autoclave Aerated Concrete. Actually proposed by Grumman as part of their STS submission in the 70's it's a closed cell inorganic foam (IE mostly waterproof) with a SG of about 0.3. AFAIK it's good to 1600c and is classed as non combustible.

However it was not as light as the Lockheed tiles at 0.19 so failed the NASA performance-uber-alles test.  :(
Leaving the Shuttle tiles at $12000/m^2 installation cost (blankets were about $3000).

BTW in the early 80's NASA developed a design methodology and washer shape that allowed stress free attachment of materials with grossly different thermal coefficients of expansion, like for example ceramic tiles and Aluminum (roughly a 1:3 ratio).

And of course ceramic nuts, bolts and washers are now standard (albeit expensive) industrial parts available from several mfgs.

There's a surprising amount of stuff on the shelf. Wheather it's still being made is another matter.
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Star One

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #408 on: 07/23/2014 10:43 am »
Thanks for that.

If they wanted to man this sort of vehicle wonder what sort of G loads the pilots would experience, comparable to the Shuttle or Dream Chaser.

Offline john smith 19

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #409 on: 07/23/2014 08:40 pm »
Thanks for that.

If they wanted to man this sort of vehicle wonder what sort of G loads the pilots would experience, comparable to the Shuttle or Dream Chaser.
Unlikely. Designed unmanned suggests they will be running a lower safety factor (1.25 Vs 1.4 for crew) and a higher acceleration. ELV's hit something like 8g. I don't know if XS-1 will do this but higher acceleration means lower gravity losses, which is good. How high they go will probably be part of the design choices of the different teams.
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

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Offline PeanutGallery

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #412 on: 07/23/2014 09:31 pm »
http://masten.aero/2014/07/xs-1pr/
Is it me, or does the image that's included in this article of a winged vehicle seem to not quite jibe with David Masten's quote:
Quote
Company founder and CTO David Masten said, “....XS-1 is a great program to join with our vertical landing technology.”

I guess having wings wouldn't preclude a vehicle from landing vertically, but aren't wings mainly for re-entry and fly back?...the extra weight seems like a loss, unless I'm missing something.  ???

Offline QuantumG

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #413 on: 07/23/2014 09:58 pm »
https://twitter.com/dmasten/status/492064889360244736

Quote from: Dave Masten
Quote from: QuantumG
@mastenspace yeah, what's with the wings dude? Getting religion from @XCOR?

@QuantumG @mastenspace @XCOR actually, RTLS. But yesterday, optimizer removed the wings.

No wings no more. Thank Heinlein!
Human spaceflight is basically just LARPing now.

Offline john smith 19

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #414 on: 07/23/2014 10:01 pm »
I guess having wings wouldn't preclude a vehicle from landing vertically, but aren't wings mainly for re-entry and fly back?...the extra weight seems like a loss, unless I'm missing something.  ???
Well historically there are a class of VTOL aircraft called "tail sitters."

For any one with an awareness of the HOTOL and Skylon programmes you have to wonder why people still think putting the engines in the back for a winged high Mach vehicle is a good idea.  :(

Maybe the shift in mass properties when the 2nd stage is launched makes all the difference but my instinct is that will simply make the control problem worse, as  you've now got a (mostly) empty set of tanks up front with a big lump of engines at the back.

So whatever's going to bring that nose down is going to need a lot  of control authority.  :(

[EDIT Or of course just ditch the wings. "Optimzer says no" ? ]
« Last Edit: 07/23/2014 10:01 pm by john smith 19 »
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline TrevorMonty

Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #415 on: 07/24/2014 05:47 am »
If there are no wings, somebody needs to update Parabolic Arc with correct pictures. Lucky this is not SpaceX other wise there would be a new thread few dozen posts by now.

Offline simonbp

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #416 on: 07/24/2014 06:07 am »
Reposting the picture for posterity. Mostly to confuse them as why a vehicle with the word "Masten" written on it has WINGS. ;)
« Last Edit: 07/24/2014 06:07 am by simonbp »

Offline Star One

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Offline jongoff

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #418 on: 07/24/2014 09:06 pm »
Reposting the picture for posterity. Mostly to confuse them as why a vehicle with the word "Masten" written on it has WINGS. ;)

Apparently the Masten guys called them "Fings" instead of wings. It was still meant to take off and land vertically. I'm glad though that the optimization analysis has the "fings" going away again--they look kind of goofy on a VTVL bird.

~Jon

Offline john smith 19

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #419 on: 07/25/2014 06:47 pm »
Apparently the Masten guys called them "Fings" instead of wings. It was still meant to take off and land vertically. I'm glad though that the optimization analysis has the "fings" going away again--they look kind of goofy on a VTVL bird.
I  thought this would happen.

Well, fings ain't what they used to be.  :)

Slightly more on topic this suggests Masten is closing in on a design to fly the mission with a reasonable amount of safety margin. Which is excellent progress in a fairly short time.
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 TBC. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

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