Quote from: a_langwich on 09/20/2013 01:09 amThe 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.
The more I think about it, the more only a Grasshopper 2+ / F9R approach seems likely to fit in the budget.
Quote from: ChrisWilson68 on 09/20/2013 01:22 amQuote from: a_langwich on 09/20/2013 01:09 amThe 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 scheduleYeah, 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]
Quote from: a_langwich on 09/20/2013 01:09 amThe 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 scheduleYeah, the easiest way to do it, by far, seems like the F9R/GH2 approach. ...
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
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.
Quote from: Robotbeat on 09/20/2013 02:43 amQuote from: ChrisWilson68 on 09/20/2013 01:22 amQuote from: a_langwich on 09/20/2013 01:09 amThe 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 scheduleYeah, 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?
Quote from: a_langwich on 09/20/2013 01:09 amThe 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 scheduleYeah, 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?
Quote from: ChrisWilson68 on 09/20/2013 01:22 amQuote from: a_langwich on 09/20/2013 01:09 amThe 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 scheduleYeah, 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.)
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.
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.
Quote from: ChrisWilson68 on 09/20/2013 05:31 amI 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.
Quote from: a_langwich on 09/20/2013 06:23 amI 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.
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.)
Quote from: a_langwich on 09/20/2013 06:23 amSpaceX 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.
Maybe so, although Grasshopper 2 hasn't exactly gone Mach 10 (has it even flown?),
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.
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.
A modernized (enlarged?) X-34 with a NK-33 could easily fit DARPA's requirements.
...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....
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.
Just reread the pdf and noticed that GH/F9R style approach might not fit DARPA's long term intents for the XS-1:QuoteThe 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 ::)
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:
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.