Author Topic: DARPA Experimental Spaceplane 1 (XS-1) Program  (Read 278498 times)

Offline darkbluenine

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #60 on: 09/20/2013 03:12 AM »
I noticed that the payload for XS-1 in the proposer's day announcement (3-5Klb) essentially matches that of the classified X-42 H2O2/kerosene pop-up stage (4Klb).  Coincidence?

More on X-42:

http://en.wikipedia.org/wiki/X-42_Pop-Up_Upper_Stage
http://www.fas.org/spp/military/program/launch/x-42.htm
http://www.designation-systems.net/dusrm/app4/x-42.html

Offline a_langwich

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #61 on: 09/20/2013 04:43 AM »
The more I think about it, the more only a Grasshopper 2+ / F9R approach seems likely to fit in the budget. 

I wonder what it would cost to resurrect X-33 and finish it with some metal tanks?  It was supposed to hit Mach 13, and could maybe take the mass hit from less advanced propellant tanks and still hit Mach 10.  NASA put $922M and L-M put $357M into the vehicle.  The work remaining might fit a DARPA budget.

X-34 is an interesting data point.  IT was supposed to be a Mach 8 vehicle, and $112M was spent on the project.  Although it was too small for the stated payload, something "X-34-ish" could fit a DARPA budget.


I don't think the contractors or personnel involved in X-33 could even be put back together to finish a metal tank for DARPA's budget.

X-34?  Wikipedia says "Orbital and Rockwell withdrew less than a year after the contract was signed, because they decided the project could not be done for the promised amount."  It never got an engine, never got off the ground.  I'm afraid that may be TOO applicable a data point.  :) 

Offline ChrisWilson68

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #62 on: 09/20/2013 05:22 AM »
The more I think about it, the more only a Grasshopper 2+ / F9R approach seems likely to fit in the budget.  Mach 10 way out past atmospheric heating concerns [...]

Thing is, I doubt you could actually develop F9R/Grasshopper from scratch on the DARPA budget or schedule

Yeah, the easiest way to do it, by far, seems like the F9R/GH2 approach. ...
[No, there is another]

[Blue Origin's Vertical Rocket Takes Hop]

OK, let's call it the F9R/GH2/Blue Origin approach.  So there are two different programs that are well along this road.  Why does DARPA want to fund another to start from scratch?  Or, if they really want to have something go to mach 10 in the atmosphere, why do they want to do it the hard way when F9R and BO are showing its feasible to do it out of the atmosphere?

Or do we think SpaceX or Blue Origin will get this DARPA contract?

Offline simonbp

Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #63 on: 09/20/2013 05:27 AM »
X-33 is not really a valid comparison; this is a first stage, not an SSTO. The requirements are very different, and much more achievable than an SSTO.

X-34 is a better comparison, but it's important to remember that its failure was largely down to the very ambitious FASTRAC engine, not vehicle itself. Of course, that basic design later evolved into SpaceX's Merlin-1, so it's not impossible to imagine that it could have worked.

Plus, the real technology that X-34 was supposed to demonstrate (autonomous gliding recovery) has been well demonstrated by X-37, and isn't nearly as difficult with modern chips and sensors as it was in the late 1990s. A modernized (enlarged?) X-34 with a NK-33 could easily fit DARPA's requirements.

Offline ChrisWilson68

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #64 on: 09/20/2013 05:31 AM »
X-33 is not really a valid comparison; this is a first stage, not an SSTO. The requirements are very different, and much more achievable than an SSTO.

X-33 wasn't ever intended to be SSTO either.  It was supposed to be a purely sub-orbital demonstrator to buy down technology risk for the VentureStar, which was supposed to be SSTO.

I think the point of the other posters is that even if X-33 couldn't successfully demonstrate that VentureStar was feasible as an SSTO, the X-33 itself might have enough performance to be a reusable first stage of a two-stage launch system as envisioned by this DARPA RFP.
« Last Edit: 09/20/2013 05:31 AM by ChrisWilson68 »

Online Robotbeat

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #65 on: 09/20/2013 06:15 AM »
The more I think about it, the more only a Grasshopper 2+ / F9R approach seems likely to fit in the budget.  Mach 10 way out past atmospheric heating concerns [...]

Thing is, I doubt you could actually develop F9R/Grasshopper from scratch on the DARPA budget or schedule

Yeah, the easiest way to do it, by far, seems like the F9R/GH2 approach. ...
[No, there is another]

[Blue Origin's Vertical Rocket Takes Hop]

OK, let's call it the F9R/GH2/Blue Origin approach.  So there are two different programs that are well along this road.  Why does DARPA want to fund another to start from scratch?  Or, if they really want to have something go to mach 10 in the atmosphere, why do they want to do it the hard way when F9R and BO are showing its feasible to do it out of the atmosphere?

Or do we think SpaceX or Blue Origin will get this DARPA contract?
They might get it. And it would probably be a good thing for everyone, since neither Blue Origin nor SpaceX have ever gotten close to demonstrating fast-turnaround (i.e. one launch in a day or less for several launches in a row) like Armadillo Aerospace, Masten Space Systems, and DC-X have.
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Offline a_langwich

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #66 on: 09/20/2013 06:23 AM »
The more I think about it, the more only a Grasshopper 2+ / F9R approach seems likely to fit in the budget.  Mach 10 way out past atmospheric heating concerns [...]

Thing is, I doubt you could actually develop F9R/Grasshopper from scratch on the DARPA budget or schedule

Yeah, the easiest way to do it, by far, seems like the F9R/GH2 approach.  But then the question is, with SpaceX already so far along that road, why bother duplicating it starting from scratch?


I don't think SpaceX is going in quite the same direction, so although I think that's the approach they have in mind, it would still require custom development.  They are looking for something much less capable in the orbital payload category, for far less money per flight, so roughly Falcon 1-sized payload and price.  (Actually, 2-3x the orbital payload of F1e, at slightly less price.)  But of course it would need "Falcon 5"-ish sizing to give it the performance overhead to do the turnarounds, stage recovery, and so on.  I would think a multi-engine approach is desirable to manage the thrust difference between a heavy launch and light recovery, and the engine-out capability is nice, too.  So maybe 5-9 50k-ish lb thrust engines, to be in the right size ballpark?  I'm not sure how well the F9R concept scales down, but I guess that's TBD.

Again, though, they are asking for someone to develop a new launch vehicle all the way to an orbital launch, plus return the complete first stage for complete and virtually instant reusability (which has never been done before), and to do this for a low-low-low unit price, and a pretty low developmental price.

SpaceX is close on some of these, but how long did it take them to get Falcon 1 ironed out?  They are still working on F9R, eleven years into development.  Blue Origin might be close, too, although there is the matter of putting a payload into orbit, and we don't have any data points about the price at which they could produce an orbital launch.  I don't know if Skunk Works or Phantom Works would tackle this, but probably not for cheap.

My guess?  This is where experienced govt bidders just plan to expect cost overruns, knowing that cost in governmental contracts is where there is the most forgiveness, and knowing the original spec was just some bureaucrat's pipe dream.  If you can meet the orbit and turnaround requirements, but come in 2-3x the original price figures, maybe everybody could live with that.  If they can't, then aim for the best demos you can under the money you have left.

Offline ChrisWilson68

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #67 on: 09/20/2013 06:54 AM »
The more I think about it, the more only a Grasshopper 2+ / F9R approach seems likely to fit in the budget.  Mach 10 way out past atmospheric heating concerns [...]

Thing is, I doubt you could actually develop F9R/Grasshopper from scratch on the DARPA budget or schedule

Yeah, the easiest way to do it, by far, seems like the F9R/GH2 approach.  But then the question is, with SpaceX already so far along that road, why bother duplicating it starting from scratch?


I don't think SpaceX is going in quite the same direction, so although I think that's the approach they have in mind, it would still require custom development.  They are looking for something much less capable in the orbital payload category, for far less money per flight, so roughly Falcon 1-sized payload and price.  (Actually, 2-3x the orbital payload of F1e, at slightly less price.)

True, but that just means SpaceX would have to develop a new, smaller upper stage and put it on the F9R first stage.  Problem solved!  Since you're not expending the F9R first stage, it doesn't matter what it costs, so you can still hit the per-flight cost goal and performance target.  In fact, the upper stage would be pretty much the same for any first stage that met the goals of this DARPA RFP.

Anyway, it sounds like the first phase contract is just for sub-orbital mach 10 flights by the first stage.  The ultimate goal is to add a second stage, but that's later.  So SpaceX could just walk in with their existing Grasshopper 2, meet all the milestones of phase one, and walk away with the money.

SpaceX is close on some of these, but how long did it take them to get Falcon 1 ironed out?  They are still working on F9R, eleven years into development.

It doesn't matter if they can use their existing F9R first stage.

Blue Origin might be close, too, although there is the matter of putting a payload into orbit, and we don't have any data points about the price at which they could produce an orbital launch.

It's hard to know with Blue Origin because they're so secretive.  My sense is they're a good way behind SpaceX on this, but I don't really know.

I don't know if Skunk Works or Phantom Works would tackle this, but probably not for cheap.

My guess?  This is where experienced govt bidders just plan to expect cost overruns, knowing that cost in governmental contracts is where there is the most forgiveness, and knowing the original spec was just some bureaucrat's pipe dream.  If you can meet the orbit and turnaround requirements, but come in 2-3x the original price figures, maybe everybody could live with that.  If they can't, then aim for the best demos you can under the money you have left.

DARPA contracts don't work quite the same way as contracts for operational systems.  They generally only have a fixed pool of money available, and DARPA just tries to get as much progress as they can for that amount of money.

Offline a_langwich

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #68 on: 09/20/2013 07:11 AM »

I think the point of the other posters is that even if X-33 couldn't successfully demonstrate that VentureStar was feasible as an SSTO, the X-33 itself might have enough performance to be a reusable first stage of a two-stage launch system as envisioned by this DARPA RFP.

Maybe it could reach Mach 10, but $1.2 billion to get not even as far as one unit assembled, makes it unlikely assembly could be finished (twelve years later now?) and a flight test going for what DARPA has to spend. 

And that's to get it Mach 10. 
Still need to alter the design to include a sizable payload bay, with staging from an internal payload bay at high Mach below 100 km (or redesigning it to carry an externable payload, take your pick).  You would need to consider whether you could even reach orbit with the required payload size, given the volume and weight constraints of your payload bay design.

I don't think a sub-scale SSTO prototype makes a good design basis for the first stage of a multi-stage launch system, but ignoring that, the scale of the X-33 program was simply too large for DARPA's budget, and every part of that design would need some reworking to finish it and alter it to the new specification. 

Offline ChrisWilson68

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #69 on: 09/20/2013 07:33 AM »

I think the point of the other posters is that even if X-33 couldn't successfully demonstrate that VentureStar was feasible as an SSTO, the X-33 itself might have enough performance to be a reusable first stage of a two-stage launch system as envisioned by this DARPA RFP.

Maybe it could reach Mach 10, but $1.2 billion to get not even as far as one unit assembled, makes it unlikely assembly could be finished (twelve years later now?) and a flight test going for what DARPA has to spend. 

And that's to get it Mach 10. 
Still need to alter the design to include a sizable payload bay, with staging from an internal payload bay at high Mach below 100 km (or redesigning it to carry an externable payload, take your pick).  You would need to consider whether you could even reach orbit with the required payload size, given the volume and weight constraints of your payload bay design.

I don't think a sub-scale SSTO prototype makes a good design basis for the first stage of a multi-stage launch system, but ignoring that, the scale of the X-33 program was simply too large for DARPA's budget, and every part of that design would need some reworking to finish it and alter it to the new specification.

I agree, I doubt X-33 could be modified and finished to meet the goals of this DARPA program for the money available.

Offline a_langwich

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #70 on: 09/20/2013 07:55 AM »

I don't think SpaceX is going in quite the same direction, so although I think that's the approach they have in mind, it would still require custom development.  They are looking for something much less capable in the orbital payload category, for far less money per flight, so roughly Falcon 1-sized payload and price.  (Actually, 2-3x the orbital payload of F1e, at slightly less price.)

True, but that just means SpaceX would have to develop a new, smaller upper stage and put it on the F9R first stage.  Problem solved!  Since you're not expending the F9R first stage, it doesn't matter what it costs, so you can still hit the per-flight cost goal and performance target.  In fact, the upper stage would be pretty much the same for any first stage that met the goals of this DARPA RFP.

Anyway, it sounds like the first phase contract is just for sub-orbital mach 10 flights by the first stage.  The ultimate goal is to add a second stage, but that's later.  So SpaceX could just walk in with their existing Grasshopper 2, meet all the milestones of phase one, and walk away with the money.

Maybe so, although Grasshopper 2 hasn't exactly gone Mach 10 (has it even flown?), nor do I know if they plan to go Mach 10 with it.  Well, then, F9R first stage...except they haven't exactly fully recovered a first stage yet either, and certainly haven't done back to back flights in two days.  A fully working synthesis of Grasshopper 2 and F9R, then.  Okay. 

I don't buy the "since you're not expending the first stage, it doesn't matter what it costs" argument.  You WILL expend it, after a small finite number of uses of each part of it, you just hope to do this part replacement more gradually on the ground, rather than wholesale into the ocean.  And we know from the shuttle program, not replacing a part does not automatically save the whole cost of the part; in fact, you may struggle to spend less than the cost of the part in order to verify that it's safe to re-use the part.  Tellingly, Musk (who is not a pessimist) is aiming for perhaps a 25% cost reduction from re-use, in the time frame under discussion.  Therefore, having a first stage sized for a $50 million rocket might not work for constructing a $10 million rocket.

SpaceX is close on some of these, but how long did it take them to get Falcon 1 ironed out?  They are still working on F9R, eleven years into development.

It doesn't matter if they can use their existing F9R first stage.

True.  I was thinking about any other company bidding on the project. 

I agree with comments earlier, I think SpaceX has its plate full.  I don't think they can just use the existing F9R stage as is (because a recoverable F9R doesn't exist yet), and I don't think they want to distract either the F9R work OR the Grasshopper work for a side project that's worth less money to them than executing their current goals.  The only way it would make sense is if they can essentially win the DARPA money by inviting DARPA to watch them continue development on Grasshopper 2, and I don't think that checks all the boxes DARPA wants checked.  (For example, justifying why they spent that money.)

Could be wrong, though; we'll see if SpaceX submits a proposal.

Online Robotbeat

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #71 on: 09/20/2013 08:11 AM »
Grasshopper 2 is the same thing as a F9R first stage, with the only possible difference being ballast instead of 8 extra engines.
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Offline ChrisWilson68

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #72 on: 09/20/2013 08:16 AM »
Maybe so, although Grasshopper 2 hasn't exactly gone Mach 10 (has it even flown?),

No, it hasn't flown at all.  It might not work, but if it works as designed, it should be able to go mach 10.  If it can't, F9v1.1 won't be able to put satellites in orbit, because Grasshopper 2 is just the current F9v1.1 plus legs.

I don't buy the "since you're not expending the first stage, it doesn't matter what it costs" argument.  You WILL expend it, after a small finite number of uses of each part of it, you just hope to do this part replacement more gradually on the ground, rather than wholesale into the ocean.

True, except that the "small" part is questionable.  I think SpaceX's goal is to be able to have a large finite number of uses of each part.  I suspect they'll eventually get there, but we don't know how many iterations they'll have to do to get to that point.  I was assuming F9R works as SpaceX hopes.

And we know from the shuttle program, not replacing a part does not automatically save the whole cost of the part; in fact, you may struggle to spend less than the cost of the part in order to verify that it's safe to re-use the part.  Tellingly, Musk (who is not a pessimist) is aiming for perhaps a 25% cost reduction from re-use, in the time frame under discussion.  Therefore, having a first stage sized for a $50 million rocket might not work for constructing a $10 million rocket.

The 25% cost reduction quote might be due to a lot of things.  A big part of it might be that Musk is not counting on a lot of short-term demand elasticity.  That is, if he were to lower the price by much more, the number of additional customers might not go up by that much.  SpaceX still has to cover all their fixed costs, so even if they can reuse their first stage an unlimited number of times for free, they wouldn't be able to reduce the cost of each flight to orbit by very much if the launch rate didn't go up by a lot.

Musk has also said that long term he hopes to reduce launch costs by an order of magnitude or more.

I agree with comments earlier, I think SpaceX has its plate full.  I don't think they can just use the existing F9R stage as is (because a recoverable F9R doesn't exist yet), and I don't think they want to distract either the F9R work OR the Grasshopper work for a side project that's worth less money to them than executing their current goals.  The only way it would make sense is if they can essentially win the DARPA money by inviting DARPA to watch them continue development on Grasshopper 2, and I don't think that checks all the boxes DARPA wants checked.  (For example, justifying why they spent that money.)

Could be wrong, though; we'll see if SpaceX submits a proposal.

Yeah, we'll have to see.  I tend to agree that SpaceX might not want the distraction, unless it just pays them to do what they were going to do anyway (which it actually might).

Offline a_langwich

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #73 on: 09/20/2013 08:25 AM »
A modernized (enlarged?) X-34 with a NK-33 could easily fit DARPA's requirements.

It was air-launched, designed to reach Mach 8, with no payload or payload bay.  You might have to make a few changes to accomodate these differences.

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #74 on: 09/20/2013 08:33 AM »
...

The 25% cost reduction quote might be due to a lot of things.  A big part of it might be that Musk is not counting on a lot of short-term demand elasticity.  That is, if he were to lower the price by much more, the number of additional customers might not go up by that much.  SpaceX still has to cover all their fixed costs, so even if they can reuse their first stage an unlimited number of times for free, they wouldn't be able to reduce the cost of each flight to orbit by very much if the launch rate didn't go up by a lot.
...
THIS.
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Offline R7

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #75 on: 09/20/2013 08:42 AM »
Just reread the pdf and noticed that GH/F9R style approach might not fit DARPA's long term intents for the XS-1:

Quote
The long-term intent is for XS-1 technologies to be transitioned to support not only next-generation launch for Government and commercial customers, but also global reach hypersonic and space access aircraft.

And retracting what I said about it being obfuscated hypersonic bomber research. Does not seem obfuscated at all  ::)
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Offline ChrisWilson68

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #76 on: 09/20/2013 08:58 AM »
Just reread the pdf and noticed that GH/F9R style approach might not fit DARPA's long term intents for the XS-1:

Quote
The long-term intent is for XS-1 technologies to be transitioned to support not only next-generation launch for Government and commercial customers, but also global reach hypersonic and space access aircraft.

And retracting what I said about it being obfuscated hypersonic bomber research. Does not seem obfuscated at all  ::)

Why can't your hypersonic bomber go out of the atmosphere?  Is it that the point of the hypersonic bomber is not to look like an ICBM so you don't get nuked in return?

Really, the effect of a hypersonic bomber isn't that much different from the effect of an ICBM except that it's reusable.  If you made an ICBM that could fly back and be reused, would that fill the hypersonic bomber role?  Either a hypersonic bomber or an ICBM is just as capable of carrying both nuclear and non-nuclear payloads.

Offline john smith 19

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #77 on: 09/20/2013 09:53 AM »
I noticed that the payload for XS-1 in the proposer's day announcement (3-5Klb) essentially matches that of the classified X-42 H2O2/kerosene pop-up stage (4Klb).  Coincidence?

More on X-42:
The actual RFP lists 1000-4000lb as a  payload. But the match is quite good.

I liked the idea of the OSC "Upper Stage Flight Experiment" and I never really got what was so classified about it.

The references you listed indicated there was a problem with the composite (and IIRC common bulkhead) HTP/Kero tank and OSC were building another, but no indication if that worked.

AFAIK its never flown so it could be sitting around the AFRL warehouse.

Note that OSC RLV proposal with the same designation was also about 40 000lb, so any winged carrier vehicle is still a pretty big beast.

VTOL is looking pretty good for simplicity. Admittedly if it gives the 2nd stage any significant horizontal velocity it's going to be quite a ways downrange before separation.

I'll note that HMX has stated that Spacex will sell Merlins and he indicated they would be about $5m each. Not sure if that includes the pressurized fuel TVC actuators though.

I'm not sure what sort of deal Aerojet would give you on AJ26s.
« Last Edit: 09/20/2013 09:59 AM by john smith 19 »
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Offline ChrisWilson68

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #78 on: 09/20/2013 10:11 AM »
I'll note that HMX has stated that Spacex will sell Merlins and he indicated they would be about $5m each. Not sure if that includes the pressurized fuel TVC actuators though.

$5m an engine for Merlin is not a good deal.  SpaceX currently lists Falcon Heavy for $77.1m for up to 6.4 tons to GTO.  That FH includes 28 engines, so if you bought a FH launch and just removed the engines and threw away everything else it would only cost you $2.75m per engine.

Offline john smith 19

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Re: DARPA Experimental Spaceplane 1 (XS-1) Program
« Reply #79 on: 09/20/2013 10:43 AM »
$5m an engine for Merlin is not a good deal.  SpaceX currently lists Falcon Heavy for $77.1m for up to 6.4 tons to GTO.  That FH includes 28 engines, so if you bought a FH launch and just removed the engines and threw away everything else it would only cost you $2.75m per engine.

I never said it was a good deal. And (AFAIK) you can't buy an F9 to drive away and carve up. You buy a ticket to launch your payload on it. Everything else is pretty much Spacex's show.

What it does mean is a high thrust, high T/W  LOX/RP1 engine is available without a bidder needing to develop it from scratch. Aerojet may offer a deal on AJ26's but I've no idea what they'd charge.

Is it good enough for single day turnaround right now? Only Spacex can have anything like an answer to that.  :(
Obviously given Musk's goals they are working on the issues (and of course will have designed some known problems out from day 1) but how far have they got?

$5m/piece and you can pick them up a week Friday (or whatever) is a pretty good deal if it saves developing an engine from scratch on a (relatively) small budget and a short timescale.

Outside of these options you have the short nozzle RL10's used on the DC-X. They did a re-flight in 26 hours without removal, tear down and detailed inspection 20 years ago.  But you've got LH2 to deal with.

DARPA's "clients" are the US military. While LH2 was acceptable for SSTO for an operational system I strongly doubt they'd be happy for it on anything which required less performance and was expected to be operated and maintained by soldiers.

Yes DoD uses Delta IV and the Centaur upper stage but I'm not sure how many military personnel are actually closely involved with those vehicles, rather than ULA employees.
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