Skylon

Skylon is a proposed spaceplane designed to launch satellites and cargo into space more efficiently. It combines features of an airplane and a rocket, taking off horizontally from a runway and flying like a plane into the upper atmosphere, then using its onboard engines to reach orbit. Its innovative hybrid engine, the SABRE, cools incoming air to act as both an airbreather and a rocket, reducing the need for large fuel tanks. This approach aims to lower launch costs, enable quick reusability, and make space access more routine and affordable. However, Skylon remains in development and has yet to be built and tested.