Re:The US military is getting serious about nuclear thermal ...
by Symmetry on Monday June 22, 2020 @09:17AM
(#23599816)
You can also have solar thermal propulsion where you reflect large amounts of sunlight onto some hydrogen to heat it up before using it as propellant. The efficiency is roughly the same since in both cases you're basically limited by the melting point of your engine. Solar thermal designs tend to have lower thrust than nuclear thermal but much more thrust than solar electric.
The advantages over solar power is thrust (which, within the solar system at least, is important if you want to get somewhere fast), and the fact that it works further out from the sun, which means you could use it to get mass to the outer planets (or mars) relatively quickly. Solar propulsion, yes, is limitless, but and can reach much faster speeds, but it can take so long to reach them, that by the time you're going faster than the NTR, the NTR has already arrived at its destination.
The advantage over chemical propulsion is efficiency.