Science Realm
Science Realm is a United States Government project with the aim of creating a vertical-takeoff horizontal-landing (VTOHL) single stage to orbit (SSTO) craft, the term is also associated with the software this project uses to simulate takeoff and landing. Science Dawn. Science Realm's predecessor Science Dawn was a classified program to build a rocket-launched supersonic horizontal-take off horizontal-landing (HOTOL) SSTO spaceplane. However, it became clear that horizontal takeoff requirement was an inappropriate application of rocket thrust-to-weight ratio; the angle and relative size of rocket and earth meant the path of  least effort was almost completely vertical (completely against gravitation). Consequently, SCIENCE DAWN ended, and the focus transferred to SCIENCE REALM. Spaceplane. The Space Maneuver Vehicle (SMV) completed a successful autonomous approach and landing on its first flight test on 11 August 1998. The unmanned vehicle was dropped from a US Army UH-60 Black Hawk helicopter at an altitude of 9,000 feet, performed a controlled approach and landed on the runway. The total flight time was 90 seconds. During the initial portion of its free fall, the maneuver vehicle was stabilized by a parachute. After it is released from the parachute , the vehicle accelerated and perform a controlled glide. This glide simulated the final approach and landing phases of such a vehicle returning from orbit. Performance requirements. The project is split into four Maximum Performance Missions Sets, which attempt to define the maximum conditions for four general uses of the spaceplane. Due to the high secrecy of the project, instead of giving a threshold and objective for each mission requirement, missions sets are defined. Mark I. Demonstrator or ACTD non-orbital vehicle that can only pop up Mark II. Mark 2 defines an orbit capable vehicle with these requirements Science Realm