Thrust and propulsion require external pressure – a surface to push off of, or a medium to propel through. Without any kind of environment to repel against, thrust is impossible.
“By definition, a vacuum is devoid of matter. Space is almost an absolute vacuum, not because of suction but because it’s nearly empty.” – Jackie Faherty, Sr Scientist Dept of Astrophysics @ American Museum of Natural History NYC
“Space is a vacuum devoid of air — meaning that, unlike on Earth, there’s no atmosphere and no pressure exerted by air molecules.”
– LiveScience