Space


X-37 MSP Integrated Tech Testbed

The X-37 program was discontinued in 2003. The X-40A activities were merged with the X-37, where NASA, the Air Force, and Boeing share the cost of the program evenly. The X-37 program, originally a NASA initiative, was transferred to the Defense Advanced Research Projects Agency in 2004. NASA's original X-37 program began in l999 and ran until September 2004 when NASA transferred the program to DARPA. NASA envisioned building two vehicles, an Approach and Landing Test Vehicle, or ALTV, and an Orbital Vehicle. The ALTV 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 Labs. DARPA completed the ALTV 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's X-37B program builds upon the early development and testing conducted by NASA, DARPA and the Air Force Research Laboratory.

Pathfinder X-37 Program

The Pathfinder X-37 Program included the development of the X-37 in-space flight demonstrator, which was the first experimental vehicle to be flown in both orbital and reentry environments. The X-37, a reusable launch vehicle, was designed to operate in both the orbital and reentry phases of flight. The robotic space plane was intended at that time to play a key role in NASA's effort to dramatically reduce the cost of putting payloads into space. The USAF Space Maneuver Vehicle (SMV) and earlier programs formed the basis for the X-37 project. The Boeing core team had a heritage to the original REusable FLYback (REFLY) satellite concept. This was followed by the X-40 and X-40A programs and the incorporation of these programs into the X-37 project.

The X-37 was projected to be an orbital experimental vehicle to be lifted to orbit by the Space Shuttle or a reusable launch vehicle and returned to Earth under its own power. To be built by the Boeing Phantom Works under a cooperative agreement signed in July 1999, it was projected to be 27.5 feet long, about half the length of the Shuttle payload bay. It was expected to weigh about six tons and to have a wingspan of 15 feet, and it contains an experiment bay 7 feet long and 4 feet in diameter.

Capable of being ferried into orbit by the Space Shuttle or an expendable launch vehicle, the X-37 was to operate at speeds up to 25 times the speed of sound and test technologies in the harsh environments of space and atmospheric reentry. The X-37 would demonstrate dozens of advanced airframe, avionics and operations technologies that can support various launch vehicle and spacecraft designs. A major focus of the X-37 will seek improvement of today's spacecraft thermal protection systems. The systems now in use are fragile and expensive to maintain. After the X-37 is deployed, it would remain in orbit up to 21 days, performing a variety of experiments before reentering the atmosphere and landing on a conventional runway. Several locations are being studied for the landing site.

The X-37's on-orbit propulsion is provided by the AR-2/3, a high reliability engine with a legacy stretching back to the 1950s. Hydrogen peroxide and JP-8, a grade of kerosene commonly used as jet fuel, will propel the X-37 engine. Less toxic, more environmentally friendly and more compact than today's rocket propellants, JP-8 and hydrogen peroxide have applications for operational vehicles that could succeed the flight demonstrator.

NASA's X-37 was to test and validate technologies in the environment of space, as well as test system performance of the vehicle during orbital flight, reentry and landing. Results from the X-37 were intended to aid in the design and development of NASA's Orbital Space Plane - designed to provide a crew rescue and crew transport capability to and from the International Space Station. The X-37 was to demonstrate approximately 41 technologies aimed at significantly cutting the cost of space flight. These technologies include avionics and flight control software improvements, ground and flight operations, structures and mechanical systems, propulsion, and thermal protection system technologies.

The X-37's shape is a 120 percent scale derivative of the Air Force's X-40A, also designed and built by Boeing, which was released from a helicopter and glide-tested in 1998. The X-40A, which lacked the X-37's advanced thermal protection materials, rocket engine, experiment bay and other spacecraft systems, was released from a U.S. Army Chinook helicopter in a series of free flight tests in 2001 to reduce technical risk before flight testing the X-37.

In December 1998, NASA selected The Boeing Company of Seal Beach, Calif., for negotiations that led in July 1999 to the award of a four-year cooperative agreement to develop the X-37. Total value of the cooperative agreement, including government and Boeing contributions, was about $173 million with an approximate 50/50 sharing arrangement. The government share includes $16 million from the U.S. Air Force to demonstrate additional technologies needed to improve future military spacecraft.

As of 2001 plans called for the X-37 to be flown captive-carry on Dryden's B-52 carrier aircraft, then dropped from the B-52 for approach and landing tests later. Assembly, integration and checkout of the X-37 was planned at Boeing facilities in Palmdale and Seal Beach, Calif., in 2001 and 2002. Unpowered atmospheric tests were planned for 2002 at Edwards Air Force Base, Calif. The first unpowered flight test of the X-37 from the B-52 was planned for fall 2001. Following successful atmospheric flight tests, the X-37 was to be ferried into orbit aboard a space shuttle for orbital and atmospheric reentry test flights. The first orbital test flight, of two orbital missions, was planned for 2003.

The X-37 government team, led by NASA's Marshall Space Flight Center in Huntsville, Ala., also included NASA's Ames Research Center, Mountain View, Calif.; Kennedy Space Center, Fla.; Goddard Space Flight Center, Greenbelt, Md.; Langley Research Center, Hampton, Va.; Dryden Flight Research Center and the US Air Force Flight Test Center, both at Edwards Air Force Base. The X-37 industry team is led by The Boeing Co. of Seal Beach. Boeing facilities participating in the program are located in Seattle; St. Louis; Palmdale and Huntington Beach., Calif.

The Air Force decided to discontinue its support of the X-37 beyond FY2001. This decision increased the likelihood that these opportunities will not be realized. The Air Force claimed the X-37 Program was not specifically designed to demonstrate military technologies while on-orbit. Industry claimed, however, that the X-37 was a vital program, because of its importance in demonstrating in-space transportation operational capabilities.

NASA planned to move forward with demonstration flights involving the X-37. The X-37 may be viewed, therefore, as an initial and critical step within a long-term RLV technology development strategy for demonstrating how to operate a reusable rocket system in flight. The knowledge gained in such an undertaking would prove valuable in supporting both military and civilian space operations.




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