2020年4月10日 · To be specific, the Proton-M — a booster rocket used for decades to carry commercial and military payloads — relies on a combination of unsymmetrical dimethylhydrazine (better known as heptyl fuel) and nitrogen tetroxide. without providing any source for that claim, and no reason why that name was chosen.

Heptyl: This is how Russians refer to UDMH, aka Hydrazine. Hydrazine is very toxic and dangerous for humans to be around, and Kazakhstan has had hydrazine rained down on it many times when rockets have failed. It's nasty but no human deaths have been attributed to it as a result due to the remoteness of the region.

Can Monomethylhydrazine and Unsymmetrical dimethylhydrazine be used one in place of another for the class of the existing orbital maneuver engines (with reduced performance may be)?