On Wed, 2002-10-30 at 09:30, Andrew Case wrote: > My sense is > that the best approach is to preheat the catalyst by firing on a warm > day :-) Simple is good.
"I'm sorry, Billy, but winter came early this year, so you're going to have to wait until next year to fly to the moon." Oh wait, Billy won't be going to the moon because it's not economical to fly only on warm days. Seriously, ERPS is interested in developing technology, and if we just want to test engines, silver is fine. Catalysts that work with >90% peroxide are necessary for operational projects that soon will need to be able to deal with low temperature launches. The cermet catalyst ERPS currently occasionally has access to requires a hell of a lot more preheating than a warm day can provide anyway. And if we have to preheat beyond "warm day" level anyway, I'd rather look at metallic catalysts such as platinum or hopefully something cheaper. There are other problems with the cermet catalyst besides the necessity of preheating. It showed a tendency to form channels that would result in liquid peroxide making it all the way through the catalyst bed and flying out the nozzle at odd angles. We've talked about making spherical pellets, but nobody's come up with a good manufacturing process for that yet, and spheres are even worse than pellets for surface area:volume. This is the reason I'd much rather deal with screens or foam than with ceramics or cermets, unless someone comes up with a way to make ceramic foam, in which case I may become excited about them again :)
signature.asc
Description: This is a digitally signed message part
