On 10/30/2013 4:46 PM, Henry Spencer wrote:
The one borderline exception is spacecraft maneuvering propulsion, where there has long been interest in systems that slowly electrolyze water and store the resulting gases to be burned (much more rapidly) in a GOX/GH2 thruster. This offers a dense non-hazardous main tank and fairly high Isp, at the cost of relatively heavy and complex hardware and a constraint that burns be small and widely spaced. (And also, tricky development -- several past attempts at such systems ended in nasty explosions, in one case fatal to an experimenter. Although Tethers Unlimited recently successfully hot-fired such a system.)
Bigelow had Orion Propulsion develop such a system (water electrolysis -> stored GOX & GH2 -> orbital RCS thrusters) for their Sundancer module. Sundancer was then cancelled in favor of the larger BA330, which as of 2011 was also slated for use of such a system in one of two RCS modules it would carry. (http://images.spaceref.com/news/2011/bigelow.chrtz.isdc.pdf, page 6)
Any more recent word on how Bigelow is doing with that?RE the explosions you cite, any more details on who that happened to? Hydrogen is tricky stuff to work with, of course. It's very hard to make plumbing not leak GH2, due to the small molecular size, plus hydrogen in air is explosive in concentrations ranging IIRC from ~2% to ~70%. Very easy to end up with BOOM when working with hydrogen if you're the slightest bit careless.
Henry
