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Why do rockets get sent off to space instead of jets?
Rockets and jets are very similar, but they have one key difference that allows rockets to work and space and keeps jets limited to Earth. It's air! We have air in our atmosphere, but not in space. Jet engines use the air in the atmosphere to propell forward: a rocket has to carry the air along with it in the form of oxydizers.
Both engines need air to create the combustion that allows them to thrust forward. Jet engines use the air that's readibly available around them instead of carrying it along, so they can't go to space.