Can a rocket burn in a vacuum?
If rockets need oxygen to burn, how do they work in space?
A common argument thrown around by conspiracy theorists and moon-landing deniers is that rockets cannot function in a vacuum because they require oxygen in order to burn.
While the latter part of that sentence may be true, as you can see from the accompanying video, the former is not.
Rockets can operate in a vacuum because they carry an oxidiser, often in the form of liquid oxygen, that allows them to burn their engine fuel. Unlike jets, rockets do not get the oxygen that they need to run from the air around them.