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. 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 will 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 has 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 current 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 is 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 would 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 will 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 will 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, is to be 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, is 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 includes 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 increases the likelihood that these opportunities will not be realized. The Air Force claimed the X-37 Program is not specifically designed to demonstrate military technologies while on-orbit. Industry claimed, however, that the X-37 is 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.
X-37A Approach & Landing Technology Vehicle
The X-37 reflected in FY2003 President's Budget was an X-37 Orbital Vehicle. The FY2004 X-37 was an Approach & Landing Technology Vehicle (not the same project).
In early 2002 the Boeing Company completed the composite wings for the X-37 reusable spaceplane at its Huntington Beach, Calif., facility and delivered them to the High Desert Assembly Integration & Test facility in Palmdale, Calif. The wings of this next-generation Reusable Launch Vehicle (RLV) technology demonstrator are now co-located with the fuselage, produced by the Boeing Phantom Works prototyping center in St. Louis. The complex wings were produced by a Phantom Works composite development team at Huntington Beach using sophisticated, highly controlled machining and bonding processes. The fuselage is constructed of Graphite Bismaleimide (GrBMI), which is a high temperature composite ideally suited for reusable vehicles returning from orbit. GrBMI operates at 450oF, 100F higher than the current aluminum structure of the Space Shuttle, allowing for a thinner and lighter thermal protection system. In addition, the fuselage is primarily bonded together to minimize weight.
On Nov. 25, 2002 Boeing announced that it was awarded a NASA contract to continue development of the X-37 reusable spaceplane and conduct atmospheric and orbital flight tests. Under this $301 million Space Launch Initiative contract, which includes options through 2006, Boeing Phantom Works was to complete the final assembly of the X-37 Approach and Landing Test Vehicle and conduct an atmospheric flight test in April 2004. Then in final assembly at the Boeing Phantom Works X-Vehicle Assembly Facility in Palmdale, Calif., the X-37 is 27.5 feet in length and has a wingspan of 15 feet.
In July 2003 an approach and landing test version of the X-37, a spacecraft designed to demonstrate technologies for NASA's Orbital Space Plane Program, successfully completed structural testing at Boeing's Huntington Beach, CA, plant. The series of ground-based, proof tests were intended to verify the structural integrity of the X-37 Approach and Landing Test Vehicle. The tests apply pressure to the vehicle, simulating flight stresses and loads the X-37 may encounter in flight. The proof tests to validate the structural integrity of the airframe were successfully completed in July 2003. Atmospheric flight tests were scheduled for mid-2004. The purpose is to validate thermal effects during approach & landing (40,000 ft and below) and autonomous approach (no pilot) technology incorporating advanced thermal protection systems and design/ manufacturing techniques.
The X-37 government team was led by NASA's Marshall Space Flight Center, Huntsville, Ala., and also includes NASA's Ames Research Center, Moffet Field, Calif.; Kennedy Space Center, Fla.; Goddard Space Flight Center, Greenbelt, Md.; Langley Research Center, Hampton, Va.; Dryden Flight Research Center; and the U.S. Air Force Flight Test Center, Edwards Air Force Base, Calif.
During April 2004, the X-37 Approach and Landing Test Vehicle was to be dropped from a NASA B-52H at 45,000 feet and perform an autonomous landing on an Edwards Air Force Base runway. The test was to verify the X-37's flight dynamics and also extend the flight envelope beyond the low speed/low altitude tests carried out successfully by the sub-scale X-40A Space Maneuver Vehicle during 2001.
X-37B Orbital Test Vehicle
The Nov. 25, 2002 NASA contract initiated a design for an additional X-37 long-duration orbital vehicle, currently scheduled to be inserted into low Earth orbit by a Delta II booster in July 2006. All Boeing X-37 activities were structured to mature technologies needed for a future orbital space plane, and were designed to reduce risks for future reusable space transportation systems.
The orbital version of the vehicle was being developed to test and validate technologies in the environment of space and will test vehicle system performance during orbital flight, reentry and landing. Technologies to be demonstrated include thermal protection systems; autonomous advanced guidance, navigation and control systems; high temperature structures; conformal reusable insulation; and high temperature seals.
The purpose of the X-37 Orbital Vehicle was to provide a versatile technology demonstrator platform on which to mature, through demonstration, critical technologies required by future space transportation systems. It would validate ascent, on-orbit, and re-entry environments incorporating a broad range of technologies including autonomous (no pilot) approach and landing, advanced guidance and navigation, advanced thermal protection systems and power distribution systems, and streamlined flight operations. The Project began the formulation phase in FY03. The planning was based on a Preliminary Design Review (PDR) in CY 2004, a Critical Design Review (CDR) in early 2005, and an orbital flight test in CY 2006.
When fielded, the unpiloted and autonomously operated X-37B will be the only X-vehicle capable of conducting continuous on-orbit operations for up to 21 days. In addition, the vehicle will serve as a test bed for approximately 30 airframe, propulsion and operation technologies and gather test data in the Mach 25 (reentry) region of flight. Within the airframe itself, a variety of experiments and technologies would be tested, including a highly durable high-temperature thermal protection system and important new aerodynamic features. Its modular design also includes a seven-foot by four-foot bay for other experiments.
The Air Force is working on a space vehicle that will allow government scientists to transport advanced technology into orbit, test its capability there, then bring it home to see how it fared in the harsh environment of space. The X-37B Orbital Test Vehicle is similar to the space shuttle, except it's about a fourth the size and unmanned. The OTV can return from space on its own. The OTV gets itself ready for re-entry, descends through the atmosphere, lines up on the runway, puts down its landing gear and it does it all on its own. The vehicle will land at either Vandenberg or Edwards Air Force bases in California.
The OTV will serve as a test platform for satellites and other space technologies. The vehicle allows satellite sensors, subsystems, components and associated technology to be transported into the environment where they will be used -- space. Scientists will prepare components in the OTV's experiment bay, and then the craft is launched into space aboard an Atlas V launch vehicle. Once in space, the OTV begins testing its payload. The doors aboard the craft could simply open, exposing the experiment bay, or mission scientists could design more elaborate experiments. The OTV is a very flexible space test platform for any number of various experiments.
Being able to test parts in their actual operational environment will allow scientists to better judge how those parts will perform when deployed, so fewer redundancies may occur in future satellites. Rather than build unproven components into a high-cost satellite, with multiple layers of redundancy to make sure they work -- the Air Force can use the OTV to get those components into space to see how they respond to the environment, and make sure they work the way they were designed. "When the OTV returns to Earth, you can inspect the tested component and use that information to potentially alter your design.
The Air Force's Rapid Capabilities Office has been tasked with acquiring, testing and demonstrating the OTV. By 2006 much of the X-37B system vehicle is now being built and would soon move into a testing phase. By late 2006 the Office was getting into the subsystem and systems-wide testing, which will go on for about a year. The Air Force was projecting a first launch for the beginning of 2008.
Aviation Week reported (29 July 2008)that the "Atlas V Eastern Range launch slot that had originally been reserved for the Atlas V launch of NASA's Lunar Reconnaissance Orbiter and Lunar Crater Observation and Sensing Satellite" will instead be used for "the first mission of the USAF/Boeing X-37B space maneuvering vehicle."
After a few flight tests in space, the OTV should be ready to begin experimentation in orbit. The first flight or two will be to check out the OTV itself to make sure it works the way it is designed to. After that, the Air Force would get into the realm of using it as a reusable space test platform -- putting space components into its experimental bay and taking them to space for testing.
Though the OTV is designed to provide a testing platform for new space technologies, it is made up of several advanced, untested technologies itself. There are a number of cutting-edge technologies on the OTV besides the auto de-orbit capability. It has new thermal protection tiles underneath and high-temperature components and seals throughout that need to be proven in orbit. There will be a great deal of extremely useful data coming from the OTV on its first flights. The plan is to share this data with other government agencies such as NASA.
