Quote from: john smith 19 on 10/01/2013 07:01 pmQuote from: jongoff on 10/01/2013 05:38 pmI don't know for sure (we finished our two Phase 1 contracts a few weeks ago), but my guess would be that no they're not open, and the Proposer's Day will more likely get postponed if the gov't stays shut down for long.Good question. I thought they'd come under Defense, so not discretionary and hence stay open. I guess some bits of the DoD are less critical than others. Actually, you're right that I don't know for sure if DARPA is part of the shutdown or not. I just sent an email to the address provided for the proposer's day to see if they're delaying. If I get an answer, I'll repost it here.~Jon
Quote from: jongoff on 10/01/2013 05:38 pmI don't know for sure (we finished our two Phase 1 contracts a few weeks ago), but my guess would be that no they're not open, and the Proposer's Day will more likely get postponed if the gov't stays shut down for long.Good question. I thought they'd come under Defense, so not discretionary and hence stay open. I guess some bits of the DoD are less critical than others.
I don't know for sure (we finished our two Phase 1 contracts a few weeks ago), but my guess would be that no they're not open, and the Proposer's Day will more likely get postponed if the gov't stays shut down for long.
Given that DARPA has sliderules, too, I would suspect either that they know all of this, and are planning something different than has been described here, or else, this is RASCAL Mark II.
Knowing Jess Sponable, I don't think he is planning to execute via concept that won't be affordable/won't fly/won't work. Of course, I knew the RASCAL program manager, and was surprised how that went.
I just heard back from the DARPA XS-1 team, and apparently they're still on for the Proposer's Day next week. Apparently at least for now, they're not part of the government that has been shut down.
Sometimes when a DARPA program manager sells a program to the office leadership, they have to make compromises to get the money. But that said, I agree wholeheartedly that I don't think Jess would be even trying to startup a program that he didn't feel had a realistic shot of flying within a budget that he was confident he could get from DARPA. So, I agree that any interpretation of the requirements that implies "this would only fly if they had $1B for the program" is probably a misinterpretation. Jess ain't stupid.
The RL10A-5 used in the DC-X had quite pathetic thrust (64.7kn) and ISP (373), admittedly with a 4:1 exp. ratio.
Jeff Foust is reporting that DARPA changed its mind and will now be postponing the Proposer's Day next week, due to the gov't shutdown. Which is a bummer. Once things are up again, I'm sure they'll post a new date.
A new date will hopefully de-conflict my schedule. Depending on what the new date is, I'll try to attend and report back here. As we get closer, if folks have topics they want notes on, post here or shoot me a PM.
Returning to topic I suggested the AJ26, RL10 and Merlin 1D as active engine programmes that could have a stage built round them and have either been used in or planned for use in reusable vehicles.It did occur to me that the SSME should technically be on the list due to the disposable version for the SLS, but I think all the current ones are earmarked for launches and I've no idea what stage the expendable version is at (RS25D or E?)Can anyone suggest any others?
Yes, DARMA engine could be dark horse. They actually brought a full engine to Space Access a few years ago, it was quite solidly built; it reminded me of the V-2's engine.
I'm still curious what engine Lockheed Martin test-fired 15x as part of the RBS Pathfinder program at their Colorado R&D location. Skunk Works is in California? Didn't think they wanted to be in the engine business. Maybe it wasn't a first stage engine? Or are they working on in-house propulsion, perhaps in conjunction with XCOR's piston pump guys, perhaps with an eye toward more vertical integration to compete on pricing? Probably just a red herring. But RBS wanted AFAIK an ORSC kerolox first stage and hydrolox second, and the ORSC engine was viewed by the NRC as one of the program risks (so it would make sense to tackle the long pole in the tent first, right?).
The cupboard really is bare, especially in hydrocarbon, which is probably what XS-1 will require. I wouldn't be surprised if Phase 1 involves subsystem work, including bringing a new engine or two forward.
I scraped together a few other engines that don't meet your active program criterion, but they come close:
CHASE-10 -- LOX/CH4. 22Klb thrust. Est. 10K sec of reusability. 180 test firings to date. Heavy engine with low Isp, but that may not matter much in the XS-1 first-stage application, especially given the high reusability that the engine offers. Developed in South Korea by ex-Hyundai engineers. They established a firm in Denver called DARMA Technology to offer it in the US:http://www.darmatechnology.com/chase-10-methane-rocket-engine.html
BE-3 -- LOX/LH2. 100Klb thrust. Presumably highly reusable. At least 1 test firing at Stennis earlier this year. Developed by Blue Origin under commercial crew. I'm skeptical of big LH2 engines in these highly reliable military applications given RS-25 experience, but maybe Blue has figured out something Rocketdyne hasn't:http://rocketry.wordpress.com/2013/03/06/blue-origin-tests-its-be-3-engine/
RL-60 -- LOX/LH2. 60Klb thrust. At least restartable. Test-fired back in 2003 but shelved afterward. Replacement for RL-10; same displacement with twice the thrust and some fraction of the cost:http://www.aero-news.net/index.cfm?do=main.textpost&id=4ddce23e-0de1-4d1f-bd76-3d78da86c0ba
Raptor -- LOX/CH4 upper stage or family. AFAIK, SpaceX has not released/leaked any other details.
It will have a lower TRL, but I wonder if DARPA has some old pulse detonation engine technology from Blackswift that they might also try to leverage for XS-1?
BE-3 is a 445kN (100klbf) tap off cycle. I.e. they tap some of the combustion chamber gas and use it to run the turbopump. I understand that requires an open cycle. It's very interesting because it doesn't have a gas generator but it doesn't have the scaling problems of the expander cycle. On the other hand, it's probably not very good at isp, since you can only get to something like 900K in the turbine blades. And the Japanese have shown open cycle expander to 1.5MN. I'm guessing, thus, that it won't be run close to stoichiometric.The Raptor is known to be a staged combustion and around 3MN (they stated 650klbf). Quite a bit big than any other engine you mentioned. For first stage reusability, CH4 sort of rules, given the coking-free nature of the fuel, easiness of a fuel rich combustion cycle, it's isp (around 10s above similar RP-1) and the relative density (only 30% more than RP-1, compared to 200% of H2). I still think that they secret for the sort of development that DARPA wants would be a cycle that uses oxidizer in our atmosphere as much as possible. And in that case a fuel that uses a huge amount of oxidizer is preferred, hence, the Skylon.
Which reminds me--the DARMA guys are now just about 15min down the road, and I still haven't made it over to visit them yet this year.
Get over there and tell them they need to show up for the XS-1 proposer's day if they're not already planning to do so and to reach out to the potential vehicle builders and primes. It's probably the best shot they have of getting that engine into a vehicle.
"How it’s configured, how it gets up, and how it gets back are pretty much all on the table—we’re looking for the most creative yet practical solutions possible."
After phase 1, Sponable said DARPA will examine the cost estimates those companies will provide to develop XS-1 before making a decision on phase 2, with a goal of flight tests in 2017 or 2018."
At the STA meeting, Sponable emphasized that while XS-1 was being funded by DARPA, it was not the agency’s goal to develop a vehicle for the government. DARPA director Arati Prabhakar, he said, "wants to make sure we transition this to industry, not to the United States Air Force and not to NASA." Those agencies, he said, can instead purchase launch services using the XS-1 vehicle from the company that develops it.
There's a summary article on the XS-1 announcement(s) at the Space Review:http://www.thespacereview.com/article/2379/1A couple details are new (at least to me).One, Sponable is quoted as saying:Quote"How it’s configured, how it gets up, and how it gets back are pretty much all on the table—we’re looking for the most creative yet practical solutions possible."Going back to a point I raised earlier in the thread, it doesn't sound like XS-1 will have an RTLS requirement. If true, that opens up a lot of solution space. It may be easier/less expensive to build a second landing/launch site on some island off Africa (or wherever) and turn XS-1 around and launch back due west after an eastward launch than incorporate an RTLS capability, especially when DDT&E costs and payload mass penalties are incorporated. Also seems synergistic with non-launch applications for the military.Second, we also get a sense of schedule and programmatic content from the article:It sounds like Phase 1 is a design cycle, although I wonder if they’ll push an technologies before Phase 2.Third, the article makes clear that DARPA wants this capability to reside in industry as a service. The resulting capability is not a military or government vehicle:That sounds promising to me from a launch point-of-view. Will help minimize requirements from non-launch applications and maximize practicality/low-cost. It sounds like Sponable's management chain shares his convictions.