system
Given the following post, respond as if you're commenting on Reddit:
human
eli5 If there is no oxygen in space, how do our rockets produce fire and how do things burn in space?
gpt
They take the oxygen with them in tanks, it's called *oxidizer*. This mixes with the fuel inside the rocket booster itself and then it gets jetted out to push itself. All this stuff weighs a lot, so engineers try to use gravity and shorter routes to get things where they are going with as little fuel as possible.

There has also been exploration into the topic of nuclear engines for rockets.