Author Topic: DARPA Experimental Spaceplane 1 (XS-1) Program  (Read 419504 times)

Offline TrevorMonty

Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #720 on: 05/31/2017 11:02 am »
I don't understand the choice of hydrolox for this launcher. I expect it complicates fuelling operations and the structural design of the launcher, compared to hydrocarbons. Why did they choose hydrogen? To reuse existing engine parts?
Because Boeing offered it.
Also there not lot reuseable domestic engines that would be suitable regardless of fuel. 2x Merlin but SpaceX aren't selling or 4-5 x Be3 which Boeing didn't choose for whatever reasons.

Offline envy887

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #721 on: 05/31/2017 11:28 am »
But why use 7 tonnes for engine mass when a single SSME is 3.3 tonnes?
slightly different based on RS-25 version.
But not 3.7 tonnes different.
« Last Edit: 05/31/2017 11:29 am by envy887 »

Offline john smith 19

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #722 on: 06/03/2017 02:56 pm »
My main question remains:

Why did not REL apply for this grant?
Several reasons.
Jess Sponable, the PM for the project stated he wanted any proposal to have an already developed engine, since it's such a key part of the project. SABRE is not there yet and Sponable was adamant they did not want to sponsor an engine development programme. That said Boeing's decision to switch engines and abandon Blue for a design of unknown specification ("like" an SSME covers a very broad range of options) is very suspicious.

IIRC REL did not have a US office at the time the project started.

To compete REL would have had to a)Form a relationship with a US airframe builder b)Persuade them they would have a SABRE ready in time for the budget available or c) Persuade them they could use the win to raise more capital to develop SABRE and d)Actually raise the additional capital and develop the engine.

Which given the fickleness of UK financial markets and the grudging support of the UK government (years late) would have made this a very high risk project for them.  :(

It would have also deeply enmeshed them in the US ITAR regulations making virtually any application outside the US very difficult. Sadly this may yet happen.  :(
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 john smith 19

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #723 on: 06/03/2017 03:01 pm »
I agree with the idea of competition and trying many different paths. 
Good to know.
Quote from: ChrisWilson68
What I disagree with is the government picking the winners. 
DARPA sponsors high risk, potentially game changing projects with applications within the DoD.
Perhaps you could outline how "the government picking the winners" could be avoided?
Quote from: ChrisWilson68
This program specified the requirements too narrowly, so it funneled money into one particular path to orbit, rather than letting competition determine the most promising paths to fund.
AFAIK I the specification was entirely in terms of performance. There was no specification on how it could be done, just that it got done.
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 #724 on: 06/03/2017 05:31 pm »
My main question remains:

Why did not REL apply for this grant?
Several reasons.
Jess Sponable, the PM for the project stated he wanted any proposal to have an already developed engine, since it's such a key part of the project. SABRE is not there yet and Sponable was adamant they did not want to sponsor an engine development programme. That said Boeing's decision to switch engines and abandon Blue for a design of unknown specification ("like" an SSME covers a very broad range of options) is very suspicious.

IIRC REL did not have a US office at the time the project started.

To compete REL would have had to a)Form a relationship with a US airframe builder b)Persuade them they would have a SABRE ready in time for the budget available or c) Persuade them they could use the win to raise more capital to develop SABRE and d)Actually raise the additional capital and develop the engine.

Which given the fickleness of UK financial markets and the grudging support of the UK government (years late) would have made this a very high risk project for them.  :(

It would have also deeply enmeshed them in the US ITAR regulations making virtually any application outside the US very difficult. Sadly this may yet happen.  :(

The article in the latest issue of Spaceflight magazine suggests this technology is pretty certainly going to the US . In fact as soon as BAE purchased its way into REL this was pretty inevitable.
« Last Edit: 06/03/2017 08:45 pm by Star One »

Offline brickmack

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #725 on: 06/03/2017 08:37 pm »
I wonder what the implications of the engine choice will be on the SLS program. 2 AR-22s aren't going to last long before they need a new version. Assuming they keep flying the same airframe after those engines are dead, another RS-25 or derivative of it would be useful (there's not really any alternatives in development with the same sort of performance, and unlike expendable rockets its not really feasible to stretch the tanks on a spaceplane), or even if they do replace Phantom Express with a larger vehicle a modern RS-25 could be vaguely competitive. If Boeing can convince Aerojet to have new RS-25s in production by, say, 2024 instead of 2027 (being that its a commercial project and they don't have to play nice with Aerojet for political reasons like NASA does), that eliminates the big gap in engine availability for SLS. Combine with lower costs for the SLS engines from additional commercial demand (maybe they could even fly Boeing's engines that are near end-of-life?), and SLS might be just the slightest bit less absurd (at least able to fly more than once every 2 years, anyway). Boeings engine choice here could've been intended to aid their other major project. Alternatively, if SLS is ultimately canceled before its first 4 flights are done, Boeing could get a rather large number of RS-25Ds without needing to pay for new production

Offline AncientU

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #726 on: 06/07/2017 12:59 pm »
I wonder what the implications of the engine choice will be on the SLS program. 2 AR-22s aren't going to last long before they need a new version. Assuming they keep flying the same airframe after those engines are dead, another RS-25 or derivative of it would be useful (there's not really any alternatives in development with the same sort of performance, and unlike expendable rockets its not really feasible to stretch the tanks on a spaceplane), or even if they do replace Phantom Express with a larger vehicle a modern RS-25 could be vaguely competitive. If Boeing can convince Aerojet to have new RS-25s in production by, say, 2024 instead of 2027 (being that its a commercial project and they don't have to play nice with Aerojet for political reasons like NASA does), that eliminates the big gap in engine availability for SLS. Combine with lower costs for the SLS engines from additional commercial demand (maybe they could even fly Boeing's engines that are near end-of-life?), and SLS might be just the slightest bit less absurd (at least able to fly more than once every 2 years, anyway). Boeings engine choice here could've been intended to aid their other major project. Alternatively, if SLS is ultimately canceled before its first 4 flights are done, Boeing could get a rather large number of RS-25Ds without needing to pay for new production

At $50M+ each... those engines are not Boeing's.
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Offline brickmack

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #727 on: 06/07/2017 04:48 pm »
Not like NASA would have any better use for them if SLS dies. It would be mutually beneficial for them to hand them over cheaply. Boeing gets cheap engines, NASA gets a new cheap reusable launcher. They've sold off surplus parts for way less than they're worth before

Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #728 on: 06/13/2017 07:29 pm »
https://spaceflightnow.com/2017/06/13/boeing-darpa-to-base-xs-1-spaceplane-at-cape-canaveral/

Boeing, DARPA to base XS-1 spaceplane at Cape Canaveral
Quote
A reusable suborbital spaceplane the size of a business jet being developed by Boeing and the Defense Department’s research and development arm could be launching and landing at Cape Canaveral in 2020, officials said after the defense contractor won a competition last month to design and test the vehicle.
Quote
The spacecraft booster would return to land at one of two runways on Florida’s Space Coast: Kennedy Space Center’s Shuttle Landing Facility, a three-mile-long landing strip, or the Skid Strip at Cape Canaveral Air Force Station.
Quote
“We conducted trade studies with Blue Origin in the first phase of the program,” Sampson wrote in an email to Spaceflight Now. “Boeing selected the Aerojet Rocketdyne engine for this next phase as it offers a flight proven, reusable engine to meet the DARPA mission requirements.”
Quote
Aerojet Rocketdyne said it will provide two engines for the XS-1 program with “legacy shuttle flight experience to demonstrate reusability, a wide operating range and rapid turnarounds.”
Quote
The Phantom Express booster stage will have advanced, lightweight composite cryogenic tanks to hold the super-cold propellants feeding the AR-22 engine. Hybrid metallic-composite wings and control surfaces on the spaceplane will be fitted with “third-generation thermal protection” to withstand the rigors of hypersonic flight and re-entry temperatures of more than 2,000 degrees Fahrenheit (1,100 degrees Celsius), according to DARPA and Boeing.
« Last Edit: 06/13/2017 07:30 pm by tvg98 »

Offline Lars-J

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #729 on: 06/14/2017 12:33 am »
I'm still curious how they plan to push the XS-1 to Mach 10 while still enabling a glide back to the launch site. That's either a mighty impressive glide ratio, or the requirements are already being lowered.

Offline QuantumG

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #730 on: 06/14/2017 12:35 am »
The requirement was enough to convince Masten to (temporarily) put wings on their vehicle.
Human spaceflight is basically just LARPing now.

Offline brickmack

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #731 on: 06/14/2017 03:22 pm »
I'm still curious how they plan to push the XS-1 to Mach 10 while still enabling a glide back to the launch site. That's either a mighty impressive glide ratio, or the requirements are already being lowered.

Who said it would do both in the same mission? Mach 10 seems to be just a one-off test objective, not part of the operational flight profile. Certainly don't need to go that fast on a booster for an orbital flight. They can land it downrange somewhere on that test flight, and RTLS on all the llwer velocity tests and on orbital missions

Offline envy887

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #732 on: 06/14/2017 05:33 pm »
I'm still curious how they plan to push the XS-1 to Mach 10 while still enabling a glide back to the launch site. That's either a mighty impressive glide ratio, or the requirements are already being lowered.

Who said it would do both in the same mission? Mach 10 seems to be just a one-off test objective, not part of the operational flight profile. Certainly don't need to go that fast on a booster for an orbital flight. They can land it downrange somewhere on that test flight, and RTLS on all the llwer velocity tests and on orbital missions

I'm still curious how they are going to land downrange. Neither Vandy nor the Cape have a suitable landing strip downrange, unless they do a dog-leg and fly it up the coast?

Offline oldAtlas_Eguy

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #733 on: 06/14/2017 05:40 pm »
RocketLab has shown that for a small payload you can create an US that uses RP-1/LOX, a electrically pumped high ISP VAC engine, and very lightweight carbon composite tanks and structure. So the technology has been demonstrated that the XS-1 (if the booster works as advertised) can do a fast call-up launch of up to 1.3mt to LEO and repeat this every day for as long as necessary.

This would also mean that for the SF/DOD, that USs with payloads possibly already attached would be sitting in storage ready for mate and launch on a XS-1 within a single day time-frame. This would also presuppose that different payload types in sufficient quantity would be manufacture in groups in order to have them as needed. This changes a great deal of operational space acquisition policies. Payloads and USs are purchased like munitions (aircraft missiles).

The basic question is what is the XS-1's max carry mass for the US-"wet". and the Delta V supplied by the XS-1 at US separation. This would then give you what different US designs would be able to do in payload performance to LEO.

Offline Lars-J

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #734 on: 06/14/2017 11:27 pm »
I'm still curious how they plan to push the XS-1 to Mach 10 while still enabling a glide back to the launch site. That's either a mighty impressive glide ratio, or the requirements are already being lowered.

Who said it would do both in the same mission? Mach 10 seems to be just a one-off test objective, not part of the operational flight profile. Certainly don't need to go that fast on a booster for an orbital flight. They can land it downrange somewhere on that test flight, and RTLS on all the llwer velocity tests and on orbital missions

Even an nominal orbital launch is going to make glide-back RTLS very challenging. (Mach 5+?) Will this SSME derivative engine be able to restart? If not they are limited to...
A) hot staging
B) glide only
Either option is very challenging.

Offline groundbound

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #735 on: 06/15/2017 03:58 am »
I'm still curious how they plan to push the XS-1 to Mach 10 while still enabling a glide back to the launch site. That's either a mighty impressive glide ratio, or the requirements are already being lowered.

Who said it would do both in the same mission? Mach 10 seems to be just a one-off test objective, not part of the operational flight profile. Certainly don't need to go that fast on a booster for an orbital flight. They can land it downrange somewhere on that test flight, and RTLS on all the llwer velocity tests and on orbital missions

I'm still curious how they are going to land downrange. Neither Vandy nor the Cape have a suitable landing strip downrange, unless they do a dog-leg and fly it up the coast?

For 10 million bucks or so I bet SpaceX could be convinced to make OCISLY tailhook-compatible.

Offline john smith 19

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #736 on: 06/25/2017 12:32 pm »
Even an nominal orbital launch is going to make glide-back RTLS very challenging. (Mach 5+?) Will this SSME derivative engine be able to restart? If not they are limited to...
A) hot staging
B) glide only
Either option is very challenging.
This brings us back to the question how much like an RS25 is this engine?

Those who remember the Ares situation, where both Boeing and LM proposed RS25 US, and ARJ turning round and saying "Y'know we said SSME's could do altitude starts? Turns out they can't" should indeed be very wary of AJR's assurances on what they can (and can't) do.  :(

OTOH M10 gives the vehicle a much larger amount of KE to play with. High speed aerodynamics have also advanced a great deal since the Shuttle, so a better hypersonic glide ratio should be possible.

Taken together that (theoretically) could let the vehicle do a big (low stress) loop to bleed off energy and still have enough to execute a gliding RTLS.
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 Archibald

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #737 on: 06/25/2017 05:45 pm »
I wonder about the Block III SSME. It is kind of "second chance" for that engine which never flew with the original shuttle. Can somebody points me to documents on that engine ? never found much.

time to bring back that thread maybe ? https://forum.nasaspaceflight.com/index.php?topic=26810.0
« Last Edit: 06/25/2017 05:47 pm by Archibald »
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Offline john smith 19

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #738 on: 07/15/2017 09:22 am »
A small technical detail on M10.

The Shuttle did air data sensing by deploying dual redundant pitot booms at M5, but they only produced reliable readings below M3, when it had lost a lot of KE.

The X38 was slated to have a "flush mount" ADS with more pressure sensing pipes to cope with the surface geometry effects of being mounted in the nose. I think the X37b also uses such a system.

In principal these systems can operate to much higher Mach numbers, giving a much better idea of aerodynamic forces on the vehicle. I'm not sure if the X37b has been remote piloted during its landings or if this ability to more accurately generate air data has made that unnecessary.
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 dchill

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #739 on: 07/15/2017 11:31 pm »
...
The X38 was slated to have a "flush mount" ADS with more pressure sensing pipes to cope with the surface geometry effects of being mounted in the nose. I think the X37b also uses such a system.

In principal these systems can operate to much higher Mach numbers, giving a much better idea of aerodynamic forces on the vehicle. I'm not sure if the X37b has been remote piloted during its landings or if this ability to more accurately generate air data has made that unnecessary.

I'm guessing some of the future vehicles like the SR-72 and any Reaction Engines Limited derivatives might use something like the BAE LASSI system, unless it's still 5 years away by the time those programs go into full development.  That's assuming that technology solves some of the high mach issues.  It might be coming too late for XS-1...
http://www.baesystems.com/en/blog/lassi-laser-air-speed-sensing-instrument

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