Recently, I designed (in my head) a Hypervelocity Passenger Vehicle (just a cool name for really high speed transports). I immediately ran into engine design problems ( I like designing everything stand-alone), since regular jet engines can't get to Mach 8.8 without burning up into flames, and rocket engines are too polluting (and also I was obsessed with nuclear jet engines which doesn't use up any fuel whatsoever) So I spent roughly 2 minutes having a headache before coming up with an insane solution. A railgun-powered ramjet. (I named it Excel 1) However it would require laser-cooling systems to cool the Mach 8.8 air to a temperature where it becomes superconductive before being ejected out from the end by a railgun-style pulse engine design. My questions: At which temperature would air become superconductive? Is it possible to make a material which could sustain that temperature without shattering? Would it be possible?