Quote from: yg1968 on 09/12/2013 11:58 pmQuote from: baldusi on 09/12/2013 09:47 pmMay be they mentioned that it has to reach Mach 10 by itself (i.e. no US nor payload)? Which I think is sort of normal for expendable version.Yes. Mach 10 for the first stage or the plane.Just to be clear, the Mach 10 requirement may be met by either the reusable booster (before staging) or the expendable stage (after staging)?Thanks for any clarification.
Quote from: baldusi on 09/12/2013 09:47 pmMay be they mentioned that it has to reach Mach 10 by itself (i.e. no US nor payload)? Which I think is sort of normal for expendable version.Yes. Mach 10 for the first stage or the plane.
May be they mentioned that it has to reach Mach 10 by itself (i.e. no US nor payload)? Which I think is sort of normal for expendable version.
From the briefing it sounded to me like the Mach 10 requirement was for the reusable booster before staging.
Quote from: jongoff on 09/13/2013 05:14 pmFrom the briefing it sounded to me like the Mach 10 requirement was for the reusable booster before staging.That's disappointing. I'll have to listen to the recording.The flight rate requirements on the XS-1 slide above also seem contradictory. The test requirement is high at 10 flights in 10 days, but the system's recurring costs goals are based around a very low operational flight rate of 10 flights per year.
Quote from: darkbluenine on 09/13/2013 06:11 pmThe flight rate requirements on the XS-1 slide above also seem contradictory. The test requirement is high at 10 flights in 10 days, but the system's recurring costs goals are based around a very low operational flight rate of 10 flights per year.That's not contradictory. It's conservative.
The flight rate requirements on the XS-1 slide above also seem contradictory. The test requirement is high at 10 flights in 10 days, but the system's recurring costs goals are based around a very low operational flight rate of 10 flights per year.
Quote from: Robotbeat on 09/13/2013 06:33 pmQuote from: darkbluenine on 09/13/2013 06:11 pmThe flight rate requirements on the XS-1 slide above also seem contradictory. The test requirement is high at 10 flights in 10 days, but the system's recurring costs goals are based around a very low operational flight rate of 10 flights per year.That's not contradictory. It's conservative.I get that the annual flight rate is conservative. But the test requirement is very aggressive. It's either going to pull the development in two different, contradictory, potentially incompatible directions. Or the government is going to pay a lot to develop something it doesn't need -- a highly operational vehicle in the absence of payloads and missions to exploit the vehicle's high operational tempo.It's like the XS-1 is trying to be the spaceplane equivalent of an Antares and an F9R at the same time. Only with an even greater difference in flight rate.
Quote from: Robotbeat on 09/13/2013 06:33 pmQuote from: darkbluenine on 09/13/2013 06:11 pmThe flight rate requirements on the XS-1 slide above also seem contradictory. The test requirement is high at 10 flights in 10 days, but the system's recurring costs goals are based around a very low operational flight rate of 10 flights per year.That's not contradictory. It's conservative.I get that the annual flight rate is conservative. But the test requirement is very aggressive. It's either going to pull the development in two different, contradictory, potentially incompatible directions. Or the government is going to pay a lot to develop something it doesn't need -- a highly operational vehicle in the absence of payloads and missions to exploit the vehicle's high operational tempo....
There aren't payloads enough for a highly operational vehicle until the price can be brought down by a highly operational vehicle. The only way to break this paradox is to make a vehicle viable at both ends of the spectrum. IMHO.
Quote from: Robotbeat on 09/13/2013 07:54 pmThere aren't payloads enough for a highly operational vehicle until the price can be brought down by a highly operational vehicle. The only way to break this paradox is to make a vehicle viable at both ends of the spectrum. IMHO.Remember, this is DARPA that we're talking about. Someone in the military must think that the fast turn around maybe needed and is assuming that payloads for such a quick succession of launches would be available. Or more precisely, be required. I don't know of any mass production line of satillites going on, but it doesn't mean that they couldn't have other payloads in mind.
It sounds like someone at DARPA has concluded that the problem with RASCAL was the team selected as the winner, and not the program requirements.It would be interesting for someone to start up a new topic on the history of the RASCAL program, for the purposes of comparing and contrasting RASCAL with XS-1.
It seems to me that grasshopper 2 / 1st stage of F9R could easily fullfil these requirements. Is it likely that spacex would participate in this program?
Quote from: dkovacic on 09/14/2013 07:55 amIt seems to me that grasshopper 2 / 1st stage of F9R could easily fullfil these requirements. Is it likely that spacex would participate in this program?I'm actually not sure about that. What's F9R's staging velocity? I thought it was quite a bit short of Mach 10, something like Mach 6 or so. That said, with a much smaller upper stage on it (optimized for a 1-4klb payload), it *might* be able to do it. But then, do people really think F9R can turn around 10x in 10 days after doing a full Mach10 flight? Maybe. But I'm not totally sure.~Jon
The use of a high altitude nuclear blast would take out a major number of satillites, both civilian and military. Getting the holes in both the GPS system patched and replacing at least some of the military CNC and surveilance sats would prove critical in this kind of scenerio.
I thought RASCAL was an air-launched rocket concept where they were using some LOX injection in the jet stage's engines to allow a low-subsonic staging velocity...this seems at least to me to be fairly different.
The F-4X and RF-4X were proposals for advanced F-4E derivatives designed by General Dynamics to carry the HIAC-1 long focal length camera as part of Project Peace Jack. This project was a joint Israel-USAF study for an advanced photo-reconnaissance aircraft capable of Mach 3+ performance.The HIAC-1 camera was an advanced high-altitude reconnaissance camera that had a focal length of 66 inches which offered unparalled resolution at extreme ranges The HIAC-1 camera was originally so large and heavy that it could only be carried by the Martin/General Dynamics RB-57F. However, later versions were sufficiently slimmed down so that they could potentially be carried by smaller aircraft such as the F-4 Phantom.Israel had always wanted the HIAC-1 camera for its own use in keeping track of its Arab neighbors, but its requests had always been turned down. However, in 1971, US attitudes towards export of the HIAC-1 camera changed and approval was given for the development of a pod (designated G-139) which could carry this camera on the belly of a Phantom. The prototype G-139 pod was over 22 feet long and weighed over 4000 pounds, and was first tested on an RF-4C in October of 1971.Unfortunately, the G-139 was still so large and bulky that the performance of the Phantom when it was carrying the pod was unacceptably poor. The Peace Jack project originated in an attempt to improve the performance of the Phantom when carrying this camera. Both the USAF and the government of Israel contributed funds for the project.Rather than trying to slim down the reconnaissance pod, the original goal of the General Dynamics team was to improve the performance of the Phantom that was carrying it. The improved performance was to be obtained by using water injection for pre-compressor cooling, which would provided increased engine thrust at high altitudes. A similar system had been used successfully in the past in various F-4 record attempts. The water was to be contained in a pair of gigantic 2500-gallon tanks which were to be attached conformally to the intersection joints of the fuselage spine and the engine nacelles. The water injection system promised to give a 150 percent increase in engine thrust at altitude. In order to accommodate the increased engine thrust that would now be available, new air intakes had to be designed. The area of the intakes was to be made much larger and they were to contain a sophisticated system of internal cowls, splitter plates, vortex generators and bleeds. With the new intakes and the water injection system, it was anticipated that maximum speeds of up to Mach 3.2 and cruising speeds of up to Mach 2.7 could be attained. The project came to be known as the F-4X, although this was not an official USAF designation.Israel was clearly very interested in the F-4X, as it promised a performance which would approach that of the USAF's SR-71. This would enable it to fly unimpeded anywhere it wanted to. However, the advanced performance of the F-4X clearly made it a possible candidate for a new interceptor. Consequently, the US State Department became more than a little worried about the export of such advanced technology overseas, since it promised to give Israel a potential interceptor which was more capable than anything currently in the US arsenal, one which might one day pose a threat to the SR-71. In addition, the Air Force was itself rather nervous about the F-4X project, since it might threaten to divert support away from the F-15 program which was just then getting underway. As a result, the State Department decided to disallow export of this technology to Israel.
It seems to me that grasshopper 2 / 1st stage of F9R could easily fullfil these requirements.
Quote from: dkovacic on 09/14/2013 07:55 amIt seems to me that grasshopper 2 / 1st stage of F9R could easily fullfil these requirements.An expendable Falcon 9 stages at Mach 10. But the reusable version will stage at Mach 6.
There would probably have to be significant engine and TPS changes or testing to meet the 10-in-10 requirement, too.
It's theoretically possible, but given how much SpaceX already has on its plate, SpaceX dropping out of Stratolaunch, and Musk's focus on Mars, I don't see the company diverting itself for XS-1.
Technically, F9R doesn't have that capability, yet. We hope it will, but we don't know at this point. I've only seen one leg.