No one can hear you scream in space, but that doesn’t mean there’s no sound in space. You just have to know how to listen.
NASA has a huge archive of emissions that come from Out There that they’ve turned into audible sound waves. If you’re looking for some creepy sounds for Halloween, might I suggest plasma waves from Saturn with a side of Jupiter’s magnetosphere? Then you can finish off your mix with radar echoes from the surface of Titan followed by whatever the hell is happening with Enceladus. Pair everything with an ultra-cold liquid helium-3 and you’re good to go.