Why can't space ships use propellers or conventional airplane jets to move in space?

lothruin

Any kind of propeller or traditional turbine jet engine requires air pressure to work. Of course, there's no atmosphere in space, so such propulsion is not viable. However, certain types of closed-cycle gas turbine engines have been proposed for long-term space applications. Dec 08 03, 9:53 AM

Baloo55th

Jets would work - if you could get them out there and supply them with oxygen. Rocket engines use a mix that contains both fuel and oxygen to burn it - cos there ain't no oxygen out there like there is in the air. Propellors will work without oxygen so long as you've got some sort of gas to pull through - and something to turn them with (elastic bands will do if they're big enough!) If anyone wants to look at the British space effort, here's the link http://www.starchaser.co.uk/ It's in a factory back of Manchester way - well worth a visit. We went there with our Cubs and Scouts earlier in the year. Great. Dec 08 03, 3:38 PM

Gnomon

Rockets will work in space, but jets won't. Jets take air in and compress it and shoot it out the back at a higher speed. This won't work in space where there is no air. Rockets take air or other gases from inside the spaceship and shoot them out the back to make the spaceship go forward. Dec 08 03, 5:05 PM

lothruin

Right. Conventional jet engines are open-cycle turbine engines, meaning they pull in air from the atmosphere for compression. Incidentally, it doesn't really matter if it is oxygen or not, it has to be gaseous. There has to be some air pressure. They've developed some closed-cycle turbine jet engines that CAN be used in space because the gas they pull in comes from within a closed system. Dec 08 03, 5:43 PM