THE X-33
Scale Drawing of the X-33
The X-33, designed by Lockheed Martin, was made to be an unmanned suborbital space plane. The Lockheed X-33 design was intended to be like the shuttles in the fact that they could be stored easily and be able to be used over and over again for the missions that it may be going on. In the picture at the bottom left, it shows the testing of the X-33's Twin Linear Aerospike XRS-2200 Engines. These engines maintain its aerodynamic shape to help loose drag, also keeping the amount of power needed to get the X-33 of and going. It is a member of the class of altitude compensating nozzle engines. A space plane with a Aerospike engine uses 25-30% less fuel where most other rockets need extra thrust to get to orbit. The comparison of the forms of jet engines below shows the different designs and how they work to get thrust. In the image below is where they tested the X-33 launch facility already completed at Edwards Air Force Base.