posted on Sep, 5 2016 @ 07:39 PM
a reply to: Phage
The S400 propulsion system
burns MMH and MON...
These are very different from LOX and RP-1. They are hypergolics. Starting to find refs now...
Gunther's Amos-4 site
(as Amos-6 data is harder to find)
A forum post on MMH fuel
with a qualified
SpaceX employee reply
edit on 9/5/2016 by drphilxr because: cleaning up
"Hypergolic propellants are fuels and oxidizers that ignite spontaneously on contact with each other and require no ignition source. The easy start
and restart capability of hypergols make them ideal for spacecraft maneuvering systems. Also, since hypergols remain liquid at normal temperatures,
they do not pose the storage problems of cryogenic propellants. Hypergols are highly toxic and must be handled with extreme care.
Hypergolic fuels commonly include hydrazine, monomethyl hydrazine (MMH) and unsymmetrical dimethyl hydrazine (UDMH). Hydrazine gives the best
performance as a rocket fuel, but it has a high freezing point and is too unstable for use as a coolant. MMH is more stable and gives the best
performance when freezing point is an issue, such as spacecraft propulsion applications. UDMH has the lowest freezing point and has enough thermal
stability to be used in large regeneratively cooled engines. Consequently, UDMH is often used in launch vehicle applications even though it is the
least efficient of the hydrazine derivatives. Also commonly used are blended fuels, such as Aerozine 50 (or "50-50"), which is a mixture of 50% UDMH
and 50% hydrazine. Aerozine 50 is almost as stable as UDMH and provides better performance.
The oxidizer is usually nitrogen tetroxide (NTO) or nitric acid. In the United States, the nitric acid formulation most commonly used is type III-A,
called inhibited red-fuming nitric acid (IRFNA), which consists of HNO3 + 14% N2O4 + 1.5-2.5% H2O + 0.6% HF (added as a corrosion inhibitor). Nitrogen
tetroxide is less corrosive than nitric acid and provides better performance, but it has a higher freezing point. Consequently, nitrogen tetroxide is
usually the oxidizer of choice when freezing point is not an issue, however, the freezing point can be lowered with the introduction nitric oxide. The
resulting oxidizer is called mixed oxides of nitrogen (MON). The number included in the description, e.g. MON-3 or MON-25, indicates the percentage of
nitric oxide by weight. While pure nitrogen tetroxide has a freezing point of about -9 oC, the freezing point of MON-3 is -15 oC and that of MON-25 is
edit on 9/5/2016 by drphilxr because: more
edit on 9/5/2016 by drphilxr because: correction to ref