Mission

The X-37B Orbital Test Vehicle (OTV), is an experimental test program to demonstrate technologies for a reliable, reusable, unmanned space test platform for the US Space Force. The primary objectives of the X-37B are twofold: the development of reusable spacecraft technologies for America's future in space, and operating experiments which can be returned to, and examined, on Earth.
 

Features

The X-37B Orbital Test Vehicle is the most advanced re-entry spacecraft. Based on NASA's X-37 design, the unmanned OTV is designed for vertical launch to low Earth orbit altitudes where it can perform long duration space technology experimentation and testing. Upon command from the ground, the OTV autonomously re-enters the atmosphere, descends and lands horizonta11y on a runway. The X-37B is the first vehicle since NASA's Shuttle Orbiter with the ability to return experiments to Earth for further inspection and analysis, but with an on-orbit time of 270 days or greater, the X-37B can stay in space for much longer.
 
Technologies being tested in the program include advanced guidance, navigation and control, thermal protection systems, avionics, high temperature structures and seals, conformal reusable insulation, lightweight electromechanical flight systems, advanced propulsion systems, advanced materials and autonomous orbital flight, reentry and landing systems.
 

Background

The Department of the Air Force Rapid Capabilities Office is leading the Department of Defense's Orbital Test Vehicle initiative, by direction of the Undersecretary of Defense for Acquisition and Sustainment and the Secretary of the Air Force. The Space Force OTV effort leverages contractor and government investments in the X-37 program by the Department of the Air Force, NASA and the Defense Advanced Research Projects Agency to continue fu11-scale development and on-orbit testing of a long-duration, reusable space vehicle.
 
NASA's original X-37 program began in 1999 and ran until September 2004 when NASA transferred the program to DARPA. NASA envisioned building two vehicles, an Approach and Landing Test Vehicle, or ALTY, and an Orbital Vehicle. The ALTY validated flight dynamics and extended the flight envelope beyond the low speed/low altitude tests conducted by NASA from 1998 through 2001 on the X-40A, a sub-scale version of the X-37 developed by Air Force Research Laboratory. DARPA completed the ALTY portion of the X-37 program in September 2006 by successfully executing a series of captive carry and free flight tests. NASA's X-37 Orbital Vehicle was never built, but its design was the starting point for the Air Force's X-37B Orbital Test Vehicle program.
 
The Air Force has successfully flown and recovered six X-37B missions, OTV-1 through OTV-6, beginning with its first launch on April 22, 2010 from Cape Canaveral Space Force Station, Fla. OTV-1 through OTV-3 all landed successfully at Vandenberg SFB, Calif., and OTV-4, OTV-5, and OTV-6 successfully landed at Kennedy Space Center, Florida. The OTV has spent a total of 3,774 days on orbit, successfully checking out the X-37B's reusable flight, reentry and landing technologies as well as operating experiments to benefit the national space and scientific communities.