[AR] Re: [UK OFFICIAL] Moon Express - HTP/kero
- From: "John Dom" <johndom@xxxxxxxxx>
- To: <arocket@xxxxxxxxxxxxx>
- Date: Mon, 17 Jul 2017 15:17:51 +0200
Henry Spencer wrote on 140717:
...it's kinda surprising to go with peroxide when there are (generally
speaking) better alternatives available.
What alternatives, and "better" by what criteria? When you're developing
your own propulsion system, having to do every test at a hazmat site is a
tremendous pain (and a large expense), and that's what hydrazine (and even
worse, N2O4) demands. The LLNL piston-pump guys (Whitehead et al) worked
first with hydrazine and then switched to peroxide, and were much impressed
at how much easier development became.
The Mercury capsule 90 % hydrogen peroxide monopropellant RCS which used a
silver type (incl. and pure platinum screens in the end) cat packs had
proven to be unreliable. Such a pain HP thrusters were abandoned in favor of
the NTO/hydrazine fuel biprop. For Gemini, Apollo and all deep space
projects that is.
Later exceptions were Scout, Soyuz, rocketbelt maniacs, ... whose thrusters
or turbopumps use catalytically decomposed monoprop peroxide to this day.
John
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