# Are there any situations where hot rather than cold propellants might be advantageous?

Given that cryogenic fuel and oxidisers exist, I wonder if the reverse is workable.

Are there fuels or oxidisers that have been considered for rockets that must be kept hot to be usable? By hot I mean significantly above room temperature to reach either liquid or gaseous form, whatever needed for the engine.

• Opposite, as in not cryogenic, or opposite, as in much hotter than room temperature? – Nathan Tuggy Apr 12 '18 at 23:01
• I am not familiar with the term thermogenic, and googling it mostly turns up references in the medical field. Can you clarify your question, perhaps giving some reason why you think such propellants might exist? Are you asking, perhaps, about propellants that would have to be kept warm for storage? – Organic Marble Apr 12 '18 at 23:31
• From an impulse perspective added beryllium would make a nice fuel. 1560K melting point would make it pretty "thermogenic" I guess. So a rocket using LOX, LH2 and LBe would perform a lot better than even LOX/LH2 (5295 m/s vs 4462 m/s acc. Wikipedia). Note that while cryogenics boil off, thermogenics would freeze which probably keeps them from being practical. – Christoph Apr 13 '18 at 6:50
• +1 good job on the rewrite! There are already four votes to re-open, almost there! – uhoh Apr 16 '18 at 3:41
• @Paul I was mainly thinking of using elrments or compounds that are solid at room temperature as fuels. If we could use gaseous carbon and liquid oxygen in an engine that would be very helpfull for in sitiu resource utilization on mars for example. – lijat Apr 22 '18 at 20:24