Well, you know me quark, now I have to rush to the defence of peroxide! Seriously though, is Isp that bad? I thought it was only slightly worse than MMH/NTO. What combination were you thinking of?
Honestly, what it comes down to is that I don't think HTP really gains you all that much, compared to more developed systems. It's not that it's bad, it's that the trade isn't positive enough.
(or NOFBX once proven safe and reliable)
But I think you are right for spacecraft that don't return to Earth. I see no rush to replace traditional hypergolics with something less toxic or corrosive in that field. To the degree there is an urge to use HAN / ADN it seems to be driven more by a desire for higher Isp than monopropellant hydrazine than by a desire for better handling characteristics.
As far as pulling this back to micro-rocketry, my propellant choice, if I were head designer, would be biprop N2O with Ethanol.
Quote from: strangequark on 11/07/2011 02:48 pmAs far as pulling this back to micro-rocketry, my propellant choice, if I were head designer, would be biprop N2O with Ethanol.Any specific reason to prefer N2O over HTP or ethanol over IPA?
The physical limit is the atmospheric drag, so I've made a quick-and-dirty spreadsheet to evaluate it.The spreadsheet finds properly that air drag is tiny at normal-sized launchers, like 50m/s performance wasted by Vega, which is compact but accelerates strongly. That explains why Energiya or the SSTL were as streamlined as a cathedral.
This site might be of interest :-http://sugarshot.org/It is almost the opposite in that very low grade propellant (sugar and potassium nitrate) is used and the goal is to reach 100km rather than orbit.