Green salty propellant

Nicolas Rasmont, Emil J. Broemmelsiek, and Joshua L. Rovey at Illinois propose a "salt-based" propellant, under megapascal-range pressure (Earth pressure is 100 kPa, so five times that or more). FAM-110A so-called: a green double-salt ionic liquid consisting of 41% wt. 1-ethyl-3-methylimidazolium ethyl sulfate and 59% wt. hydroxylammonium nitrate. "Imidazole" means carbon / nitrogen, which I didn't know; "ethyl" and "methyl" are, as we all should know, carbon and hydrogen. These "salts", then, are wholly non-metallic. DOI 10.1016/j.combustflame.2020.04.014.

COLOUR INTO SPACE 5/3/22: "Green" is a figure of speech. Hydroxylammonium nitrate, or AF-M315E, has salmon hue. NASA was already testing this as of the time of poasting, although maybe not with this 1-ethyl-3-methylimidazolium ethyl sulfate.

They are looking to smaller satellites; also, as a replacement for hydrazine which, you'll remember from Europa Report, is poison. The pressurising agent is nitrogen gas but assuredly they can use helium where that's more economic, like on the Moon. I am unsure if the nitrogen is mixed with the two reagents - I expect, not, as it would dilute the mix. And they are looking to deep space, raising the specific-impulse... I don't think they are rocketing stuff out a major planet's well, like Branson promises.

For Venus, that's moot. The ambient pressure gets into the 500 kPa range at, what, 35 km altitude and below. At 3 mPA = 30 bar, where the burn rate is reliable (0.142 ± 0.029 m/s): 17 km on down. Said atmosphere, CO₂ and N₂, is additionally inert. No need for added gas down here! And besides the hydrogen, all the other elements are readily available in the air and haze. Rasmont's crew does warn against water intake from the atmosphere, but on Venus - LOL.

A more serious question here would be, at what temperature do these (pressurised) reagents spontaneously combine in the heat - or, if separate, decompose and/or turn to gas. I'd fill the fuel-tanks in a chilled pressurised environment; the tanks themselves would be insulative. Except where they're ignited. Which is done when I open the bay doors to the outside.

Considering Venus' insane drag, I don't see this being blasted from the surface. To get from surface to cloud, Venereans use balloons and/or tethered kites. I wonder instead about jet turbines.