I didn’t mention it last week, because I was having posting problems, but Leonard David has a good overview of the program, with some quotes from Yours Truly.
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I didn’t mention it last week, because I was having posting problems, but Leonard David has a good overview of the program, with some quotes from Yours Truly.
Comments are closed.
Very nice article and interview. 🙂
On top of my very long comment (or two) over at Selenian Boondock’s post on the XS-1 program, suggesting the odd horizontally-oriented vertical launch and landing mode to reduce facilities and labor, is my worry that it’s possibly to meet the XS-1 relatively modest payload goals with a more conventional hypersonic vehicle, but one that wouldn’t have any significant growth potential.
There are reasonable size limitations for pure aerodynamic takeoff (due to scaling laws for wing structural weights), and if the vehicle is very large and expensive then upscaling becomes problematic. As I recall, the XS-1 payload requirements to LEO are 0.5 to 2.5 tons. The Falcon 9 v1.1 has a LEO capability of about 14 tons, and they can carry small satellites as revenue-generating secondary payloads, as can the other commercial launch firms.
If the XS-1 works, dramatically lowering the cost and ease of putting the small satellites into orbit, yet relies on an architecture that can’t be conveniently upscaled to put 7 to 10 ton payloads into orbit (never mind larger ones), it might prove more a hindrance to space development than a leap forward. It could deprive the commercial launch industry of the secondary revenue streams (and ease of market entry with a smaller initial capability), while creating a serious break-point in the cost structure, such that more and more satellite makers try to squeeze into the lower cost, lower mass niche. Such a situation would arise if it costs $1 million to put a 2 ton satellite up ($250/lb), but $30 million to put a 6 ton satellite up ($2500/lb).
So if I was in DARPA’s position, and the goal is to make technological or architectural breakthroughs in launch costs and flight right that can be applied towards future development, I’d be wary of approaches that are somewhat “brute force”, such as pushing the size of the launching aircraft to the technological limits just to deliver a relatively tiny payload, however cheap and convenient it may be for the exact application of launching small satellites. The military, of course, probably won’t see it that way, because they could really make use of the capabilities stated as the program’s goals.