For comparison, a nuclear spaceflight to Mars would consume tons upon tons of chemical fuel.

相比之下，前往火星的核航天飞行将消耗成吨的化学燃料。

Gone are the days of heavy chemical fuel burns and trans-Mars injection orbits.

得花上数天时间，消耗大量化学燃料，才能将飞船送入火星转移轨道。