Quote from: john smith 19 on 07/14/2016 11:18 amBut smallsats mean that a relatively small LV can now deploy a LEO constellation in one launch to deliver continuing capability over that area as they rise and set over the regions local horizon, as well as all areas along their orbital track. No I would not say this is a cost effective solution long term but that's not the point. The goal is quick response to sudden threats which can be resolved and the space assets left to reenter when their job is done.
But smallsats mean that a relatively small LV can now deploy a LEO constellation in one launch to deliver continuing capability over that area as they rise and set over the regions local horizon, as well as all areas along their orbital track. No I would not say this is a cost effective solution long term but that's not the point. The goal is quick response to sudden threats which can be resolved and the space assets left to reenter when their job is done.
Quote from: Rocket Science on 07/13/2016 08:02 pm10 flights in 10 days seem like someone has been reading from Elon's playbook. You have that backward. Sponable was Project Manager for the DC-X project that demonstrated 2 flights in 26 hours for a M3 capable LH2 fueled vehicle 25 years ago.
10 flights in 10 days seem like someone has been reading from Elon's playbook.
Quote from: whitelancer64 on 07/13/2016 11:00 pmTo expound: DARPA is a military think tank. 200 geniuses in an office building doing nothing but thinking of how to win the next big war.Urban myth. That is not what DARPA is. DARPA employees are not doers, they are funders and project managers. They have other groups do the work.
To expound: DARPA is a military think tank. 200 geniuses in an office building doing nothing but thinking of how to win the next big war.
Great NSF article. However I'm still scratching my head over this DARPA effort.Yes, reusable launch systems are good things to pursue, but it really does seem like they are ignoring current events. For instance, wouldn't it make sense to focus on current technologies to see how far they can go?I guess what bothers me is that DARPA is being overly specific about what they want, such as the 10 launches in 10 days, and to me fake requirements breed capabilities that don't match reality - which means the systems could end up being unsustainable (i.e. why not 5 in 10 days, or??). Not unlike the Shuttle, which was supposedly designed for high reusability, yet there wasn't a need for it's full capabilities.It just seems like DARPA has skipped too far ahead of this issue, and is missing out on surveying WHAT IS POSSIBLE using the technologies that have far less risk. Especially since they point out that this effort has a TRL of 5, and the X-33 program, which was very challenging, had a TRL of 3. Plus they don't have much money, which further muddies things. I think their risk/reward ratio is not right.As an example, what if instead of focusing on an SSTO that has a low payload capability, that they focused on using existing reusable stage technology, and added a reusable upper stage? Which is essentially what Elon Musk had originally hoped he could do with the Falcon family, but I think they found such a capability was a lower priority than the various other efforts they were working.Any who, still watching this with a curious eye...
Quote from: john smith 19 on 07/13/2016 09:23 pmQuote from: Rocket Science on 07/13/2016 08:02 pm10 flights in 10 days seem like someone has been reading from Elon's playbook. You have that backward. Sponable was Project Manager for the DC-X project that demonstrated 2 flights in 26 hours for a M3 capable LH2 fueled vehicle 25 years ago.As someone on aRocket pointed out. Apparently they actually had the vehicle ready to fly in only 8hrs once, but the White Sands range personnel didn't want to stick around past the end of their formal shift, so they made them come back and fly again the next day.~Jon
This is something that really deserves to be better known. The folklore around LH2 is that it's very maintenance heavy, based on the record of the SSME but this has a lot to do with the staged combustion cycle using the partially combusted propellant to drive the turbines directly.Avoiding staged combustion, or separating the heating from the turbine driving (like SABRE) radically changes support. issues.
You're not wrong, wrt using combustion products directly as turbine drive gas. Aside from thermal effects, combustion products make for some fun failure modes, even with hydrolox (you have water vapor running through the same machine as cryogens). I will say, however, that a helium HEX loop, or any large use of helium, does negatively affect operability. It's a really nice coolant, but damn does it leak. Of course, so does hydrogen...through single crystal metal.
This all sounds like it's related to the Launch Cost Elasticity discussion, except that AFAICS the rapid turn around isn't even a nice to have requirement.
<snip>That is launch on demand, not launch-on-whenever-the-launch-services-company-has-a-gap-in-its-schedule. As a services that is quite attractive.
Quite attractive to whom? I find it very hard to imagine any customer with the possible exception of the military (or NSF etc.) who would have any interest in such a capability.
While this might be something the government could see a need for, it's equally something that likely (hopefully) would never be used.
That doesn't sound like a good basis for a company to invest a lot of money to build a system for.It seems to me analogous to a company spending a lot of its own money on designing Minuteman silos.
That suggests you've spent too long thinking the ELV mindset. No other transport medium requires you to book a ticket for a chance to take a trip (given the roughly 1 in 50 failure rate) years in advance of the date of travel.No other medium stops you from owning the means of transport. No one buys a rocket, they buy a chance put their payload on a rocket.
Anyone want to make educated guesses on who takes the Phase II contract? I personally hope Masten wins it, but I think Northrop Grumman taking it is almost a given at this juncture. I think Boeing is unlikely to win since they were publicly uncomfortable with the internal contributions and I think they still have egg on their face in DARPA's eyes from the ALASA debacle.
The contract, proposed through Vector's acquired Garvey Spacecraft Corporation subsidiary, complements an earlier SBIR award from the Defense Advanced Research Projects Agency (DARPA) that addresses the use of the Vector-R first stage as a second stage for the XS-1 Experimental Spaceplane.
http://defensenews-alert.blogspot.com/2016/09/vector-space-systems-awarded-25m-in.htmlQuoteThe contract, proposed through Vector's acquired Garvey Spacecraft Corporation subsidiary, complements an earlier SBIR award from the Defense Advanced Research Projects Agency (DARPA) that addresses the use of the Vector-R first stage as a second stage for the XS-1 Experimental Spaceplane.Seems to be the only XS-1 related news lately. Anyone got something better?
As previously discussed in the VSS thread;http://www.prnewswire.com/news-releases/vector-space-systems-completes-acquisition-of-garvey-spacecraft-corporation-to-enhance-micro-satellite-launch-capabilities-300301053.html