"It's simply easier to ignite - that seems like a really bad reason to use it."
LOL that's what makes injector design and combustion instability less of a problem than for kero/LOX. Its not a bug, its a huge feature. Aside from hard starts being chemically impossible, screaming combustion modes are less likely. This means a more reliable and cheaper rocket because the ignition system that doesn't exist, can't fail, and the cooling system doesn't have to worry about screaming modes melting thru, and the injectors don't have to have weird performance robbing (heavy) acoustic baffles.
Well, these are all relative. You can still screw up the cooling system of a hypergolic nozzle or make it scream (think about it, a rocket engine is just a giant gigawatt class whistle, after all). Its just harder to screw up than nonhypergolic.
Finally from a chemical standpoint they're not environmentally stable toxins. Organomercury compounds, or tetraethyl lead, now those would be bad ideas to spray all over the environment. But UDMH and Nit Tet are "shelf stable" but not "environmentally stable". Oh they suck all right but they're going to "poison the land" for about a day, not a millenia or basically permanently. Both break down into completely harmless stuff. Of course before they breakdown, or if they end up breaking down in your liver, then not so good.
LOL that's what makes injector design and combustion instability less of a problem than for kero/LOX. Its not a bug, its a huge feature. Aside from hard starts being chemically impossible, screaming combustion modes are less likely. This means a more reliable and cheaper rocket because the ignition system that doesn't exist, can't fail, and the cooling system doesn't have to worry about screaming modes melting thru, and the injectors don't have to have weird performance robbing (heavy) acoustic baffles.
Well, these are all relative. You can still screw up the cooling system of a hypergolic nozzle or make it scream (think about it, a rocket engine is just a giant gigawatt class whistle, after all). Its just harder to screw up than nonhypergolic.
Finally from a chemical standpoint they're not environmentally stable toxins. Organomercury compounds, or tetraethyl lead, now those would be bad ideas to spray all over the environment. But UDMH and Nit Tet are "shelf stable" but not "environmentally stable". Oh they suck all right but they're going to "poison the land" for about a day, not a millenia or basically permanently. Both break down into completely harmless stuff. Of course before they breakdown, or if they end up breaking down in your liver, then not so good.