Liquid Neon Rocket Design

[samblohm]

It is my understanding that when neon goes from a liquid to a gas, it has an expansion ratio of 1:1400. Would using N- and N+ be a realistic rocket fuel? I understand that it would take a lot of energy but is there a way to figure out how much?

[Bob S]

Are you talking about operating below the triple point (-229 deg C)? Or are you talking about using it as supercritical fluid at room temp? At what pressure?

[Mech_Engineer]

It's probably best to look at a potential fuel from a stored energy standpoint than an expansion ratio standpoint. Water-steam has an expansion ratio of about 1:1700, but the expansion actually requires energy added, making water by itself useless as a rocket fuel (however Hydrogen Peroxide H2O2 is useful with a catalyst because it is an exothermic reaction and creates steam and oxygen).