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The Boeing X-37, also known as the Orbital Test Vehicle (OTV), is a reusable
robotic spacecraft Uncrewed spacecraft or robotic spacecraft are spacecraft without people on board. Uncrewed spacecraft may have varying levels of autonomy from human input, such as remote control, or remote guidance. They may also be autonomous, in which t ...
. It is boosted into space by a
launch vehicle A launch vehicle is typically a rocket-powered vehicle designed to carry a payload (a crewed spacecraft or satellites) from Earth's surface or lower atmosphere to outer space. The most common form is the ballistic missile-shaped multistage ...
, re-enters Earth's atmosphere, and lands as a
spaceplane A spaceplane is a vehicle that can flight, fly and gliding flight, glide as an aircraft in Earth's atmosphere and function as a spacecraft in outer space. To do so, spaceplanes must incorporate features of both aircraft and spacecraft. Orbit ...
. The X-37 is operated by the Department of the Air Force Rapid Capabilities Office, in collaboration with the United States Space Force, for orbital spaceflight missions intended to demonstrate reusable space technologies. It is a 120-percent-scaled derivative of the earlier Boeing X-40. The X-37 began as a
NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...
project in 1999, before being transferred to the
United States Department of Defense The United States Department of Defense (DoD, USDOD, or DOD) is an United States federal executive departments, executive department of the federal government of the United States, U.S. federal government charged with coordinating and superv ...
in 2004. Until 2019, the program was managed by Air Force Space Command. An X-37 first flew during a drop test in 2006; its first orbital mission was launched in April 2010 on an Atlas V rocket, and returned to Earth in December 2010. Subsequent flights gradually extended the mission duration, reaching in orbit for the fifth mission, the first to launch on a
Falcon 9 Falcon 9 is a Reusable launch system#Partial reusable launch systems, partially reusable, two-stage-to-orbit, medium-lift launch vehicle designed and manufactured in the United States by SpaceX. The first Falcon 9 launch was on June 4, 2010, an ...
rocket. The sixth mission launched on an Atlas V on 17 May 2020 and concluded on 12 November 2022, reaching 908 days in orbit. The seventh mission launched on 28 December 2023 on a Falcon Heavy rocket, entering a highly elliptical high Earth orbit, landing in March 2025 after 434 days in orbit.


Development


Origins

In 1999, NASA selected Boeing Integrated Defense Systems to design and develop an orbital vehicle, built by the California branch of Boeing Phantom Works. Over four years, $192 million was spent on the project, with NASA contributing $109 million, the U.S. Air Force $16 million, and Boeing $67 million. In late 2002, a new $301 million contract was awarded to Boeing as part of NASA's Space Launch Initiative framework. The aerodynamic design of the X-37 was derived from the larger Space Shuttle orbiter, hence the X-37 has a similar lift-to-drag ratio, and a lower cross range at higher altitudes and Mach numbers compared to DARPA's Hypersonic Technology Vehicle. An early requirement for the spacecraft called for a total mission delta-v of for orbital maneuvers. An early goal for the program was for the X-37 to rendezvous with satellites and perform repairs. The X-37 was originally designed to be carried into orbit in the cargo bay of the Space Shuttle, but underwent redesign for launch on a Delta IV or comparable
rocket A rocket (from , and so named for its shape) is a vehicle that uses jet propulsion to accelerate without using any surrounding air. A rocket engine produces thrust by reaction to exhaust expelled at high speed. Rocket engines work entirely ...
after it was determined that a shuttle flight would be uneconomical. The X-37 was transferred from NASA to the Defense Advanced Research Projects Agency (DARPA) on 13 September 2004. Thereafter, the program became a classified project because of its military applications. DARPA promoted the X-37 as part of the independent space policy that the
United States Department of Defense The United States Department of Defense (DoD, USDOD, or DOD) is an United States federal executive departments, executive department of the federal government of the United States, U.S. federal government charged with coordinating and superv ...
has pursued since the 1986 ''Challenger'' disaster.


Glide testing

The X-37A vehicle that was used as an atmospheric drop test glider had no propulsion system. Instead of an operational vehicle's payload bay doors, it had an enclosed and reinforced upper
fuselage The fuselage (; from the French language, French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds Aircrew, crew, passengers, or cargo. In single-engine aircraft, it will usually contain an Aircraft engine, engine as wel ...
structure to allow it to be mated with a mothership. In September 2004, DARPA announced that for its initial atmospheric drop tests the X-37A would be launched from the Scaled Composites White Knight, a high-altitude research aircraft. On 21 June 2005, the X-37A completed a captive-carry flight underneath the White Knight from
Mojave Spaceport The Mojave Air and Space Port at Rutan Field is in Mojave, California, United States, at an elevation of . It is the first facility to be licensed in the United States for horizontal launches of reusable spacecraft, being certified as a spa ...
in Mojave, California. Through the second half of 2005, the X-37A underwent structural upgrades, including the reinforcement of its nose wheel supports. The X-37A's public debut for its first free flight, scheduled for 10 March 2006, was canceled due to an Arctic storm. The next flight attempt, on 15 March 2006, was canceled due to high winds. On 24 March 2006, the X-37A flew again but a datalink failure prevented a free flight and the vehicle returned to the ground still attached to its White Knight carrier aircraft. On 7 April 2006, the X-37A made its first free glide flight. During landing, the vehicle overran the runway and sustained minor damage. Following the vehicle's extended downtime for repairs, the program moved from Mojave to Air Force Plant 42 in Palmdale, California, for the remainder of the flight test program. White Knight continued to be based at Mojave, though it was ferried to Plant 42 when test flights were scheduled. Five additional flights were thought to have been performed,Source of flights: mission markings posted on side of White Knight aircraft two of which resulted in X-37 releases with successful landings. These two free flights occurred on 18 August 2006 and 26 September 2006.


X-37B Orbital Test Vehicle

On 17 November 2006, the U.S. Air Force announced that it would develop its own variant of NASA's X-37A. The Air Force version was designated the X-37B Orbital Test Vehicle (OTV). The OTV program was built on earlier industry and government efforts by DARPA, NASA, and the Air Force under the leadership of the Air Force Rapid Capabilities Office in partnership with NASA and the
Air Force Research Laboratory The Air Force Research Laboratory (AFRL) is a scientific research and development detachment of the United States Air Force Air Force Materiel Command, Materiel Command dedicated to leading the discovery, development, and integration of direct- ...
. Boeing was the prime contractor for the OTV program. The X-37B was designed to remain in orbit for up to 270 days at a time. The Secretary of the Air Force stated that the OTV program would focus on "risk reduction, experimentation, and operational concept development for reusable space vehicle technologies, in support of long-term developmental space objectives". The X-37B was originally scheduled for launch in the payload bay of the Space Shuttle, but after the Space Shuttle ''Columbia'' disaster, it was transferred to a Delta II 7920. The X-37B was subsequently transferred to a shrouded configuration on the Atlas V rocket, due to concerns over the unshrouded spacecraft's aerodynamic properties during launch. Following their missions, X-37B spacecraft primarily land on a runway at
Vandenberg Air Force Base Vandenberg may refer to: * Vandenberg (surname), including a list of people with the name * USNS ''General Hoyt S. Vandenberg'' (T-AGM-10), transport ship in the United States Navy, sank as an artificial reef in Key West, Florida * Vandenberg S ...
, California, with
Edwards Air Force Base Edwards Air Force Base (AFB) is a United States Air Force installation in California. Most of the base sits in Kern County, California, Kern County, but its eastern end is in San Bernardino County, California, San Bernardino County and a souther ...
as a secondary site. In 2010, manufacturing work began on the second X-37B, which conducted its maiden mission in March 2011. On 8 October 2014, NASA confirmed that X-37B vehicles would be housed at
Kennedy Space Center The John F. Kennedy Space Center (KSC, originally known as the NASA Launch Operations Center), located on Merritt Island, Florida, is one of the NASA, National Aeronautics and Space Administration's (NASA) ten NASA facilities#List of field c ...
in Orbiter Processing Facilities (OPF) 1 and 2, hangars previously occupied by the Space Shuttle. Boeing had said the space planes would use OPF-1 in January 2014, and the Air Force had previously said it was considering consolidating X-37B operations, housed at Vandenberg Air Force Base in California, nearer to their launch site at Cape Canaveral. NASA also stated that the program had completed tests to determine whether the X-37B, one-fourth the size of the Space Shuttle, could land on the former Shuttle runways. NASA furthermore stated that renovations of the two hangars would be completed by the end of 2014; the main doors of OPF-1 were marked with the message "Home of the X-37B" by this point.


Speculation regarding purpose

Most of the activities of the X-37B project are secret. The official Air Force statement is that the project is "an experimental test program to demonstrate technologies for a reliable, reusable, uncrewed space test platform for the U.S. Air Force". The primary objectives of the X-37B are twofold: reusable spacecraft technology and operating experiments, which can be returned to Earth. The Air Force states that this includes testing
avionics Avionics (a portmanteau of ''aviation'' and ''electronics'') are the Electronics, electronic systems used on aircraft. Avionic systems include communications, Air navigation, navigation, the display and management of multiple systems, and the ...
, flight systems, guidance and navigation, thermal protection, insulation, propulsion, and re-entry systems. In May 2010, Tom Burghardt speculated on ''Space Daily'' that the X-37B could be used as a spy satellite or to deliver weapons from space.
The Pentagon The Pentagon is the headquarters building of the United States Department of Defense, in Arlington County, Virginia, across the Potomac River from Washington, D.C. The building was constructed on an accelerated schedule during World War II. As ...
subsequently denied claims that the X-37B's test missions supported the development of space-based weapons. In January 2012, allegations were made that the X-37B was being used to spy on China's Tiangong-1 space station module. Former U.S. Air Force orbital analyst Brian Weeden later rejected this claim, emphasizing that the different orbits of the two spacecraft precluded any practical surveillance flybys. In October 2014, ''
The Guardian ''The Guardian'' is a British daily newspaper. It was founded in Manchester in 1821 as ''The Manchester Guardian'' and changed its name in 1959, followed by a move to London. Along with its sister paper, ''The Guardian Weekly'', ''The Guardi ...
'' reported the claims of security experts that the X-37B was being used "to test reconnaissance and spy sensors, particularly how they hold up against radiation and other hazards of orbit". In November 2016, the ''
International Business Times The ''International Business Times'' is an American online newspaper that publishes five national editions in four languages. The publication, sometimes called ''IBTimes'' or ''IBT'', offers news, opinion and editorial commentary on business and ...
'' speculated that the U.S. government was testing a version of the EmDrive electromagnetic microwave thruster on the fourth flight of the X-37B. In 2009, an EmDrive technology transfer contract with Boeing was undertaken via a State Department TAA and a UK export license, approved by the UK Ministry of Defence. Boeing has since stated that it is no longer pursuing this area of research. The U.S. Air Force has stated that the X-37B is testing a Hall-effect thruster system for Aerojet Rocketdyne. In July 2019, former
United States Secretary of the Air Force The secretary of the Air Force, sometimes referred to as the secretary of the Department of the Air Force, (SecAF, or SAF/OS) is the head of the United States Department of the Air Force, Department of the Air Force and the service secretary for ...
Heather Wilson explained that when an X-37B was in an elliptic orbit it could, at perigee, use the thin atmosphere to make an orbit change preventing some observers from discovering the new orbit for a while, permitting secret activities.


Processing

Processing for the X-37 is carried out inside Bays 1 and 2 of the Orbiter Processing Facility (OPF) at
Kennedy Space Center The John F. Kennedy Space Center (KSC, originally known as the NASA Launch Operations Center), located on Merritt Island, Florida, is one of the NASA, National Aeronautics and Space Administration's (NASA) ten NASA facilities#List of field c ...
in Florida, where the vehicle is loaded with its payload. The X-37 is then placed inside a fairing along with its stage adapter and transported to the launch site. Previous launch sites have included SLC-41 and Kennedy Space Center LC-39A. Landing is at one of three sites across the US: the
Shuttle Landing Facility The Shuttle Landing Facility (SLF), also known as Launch and Landing Facility (LLF) , is an airport located on Merritt Island, Florida, Merritt Island in Brevard County, Florida, Brevard County, Florida, United States. It is a part of the Kennedy ...
at Kennedy Space Center,
Vandenberg Space Force Base Vandenberg Space Force Base , previously Vandenberg Air Force Base, is a United States Space Force Base in Santa Barbara County, California. Established in 1941, Vandenberg Space Force Base is a space launch base, launching spacecraft from the ...
, or
Edwards Air Force Base Edwards Air Force Base (AFB) is a United States Air Force installation in California. Most of the base sits in Kern County, California, Kern County, but its eastern end is in San Bernardino County, California, San Bernardino County and a souther ...
. To return to Kennedy Space Center, the X-37 is placed into a payload canister and loaded into a
Boeing C-17 The McDonnell Douglas/Boeing C-17 Globemaster III is a large military transport aircraft developed for the United States Air Force (USAF) between the 1980s to the early 1990s by McDonnell Douglas. The C-17 carries forward the name of two prev ...
cargo plane. Once at Kennedy, the X-37 is unloaded and towed to the OPF, where it is prepared for its next flight. Technicians must wear protective suits due to toxic hypergolic gases.


Design

The X-37 Orbital Test Vehicle is a reusable robotic
spaceplane A spaceplane is a vehicle that can flight, fly and gliding flight, glide as an aircraft in Earth's atmosphere and function as a spacecraft in outer space. To do so, spaceplanes must incorporate features of both aircraft and spacecraft. Orbit ...
. It is an approximately 120-percent-scale derivative of the Boeing X-40, measuring over in length, and features two angled tail fins. The X-37 launches atop an Atlas V 501 or a SpaceX
Falcon 9 Falcon 9 is a Reusable launch system#Partial reusable launch systems, partially reusable, two-stage-to-orbit, medium-lift launch vehicle designed and manufactured in the United States by SpaceX. The first Falcon 9 launch was on June 4, 2010, an ...
or Falcon Heavy rocket. The spaceplane is designed to operate in a speed range of up to
Mach The Mach number (M or Ma), often only Mach, (; ) is a dimensionless quantity in fluid dynamics representing the ratio of flow velocity past a Boundary (thermodynamic), boundary to the local speed of sound. It is named after the Austrian physi ...
25 on its reentry. The technologies demonstrated in the X-37 include an improved thermal protection system, enhanced
avionics Avionics (a portmanteau of ''aviation'' and ''electronics'') are the Electronics, electronic systems used on aircraft. Avionic systems include communications, Air navigation, navigation, the display and management of multiple systems, and the ...
, an autonomous guidance system and an advanced airframe. The spaceplane's thermal protection system is built upon previous generations of atmospheric reentry spacecraft, incorporating
silica Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , commonly found in nature as quartz. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and abundant f ...
ceramic A ceramic is any of the various hard, brittle, heat-resistant, and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porcela ...
tiles. The X-37's avionics suite was used by Boeing to develop its CST-100 crewed spacecraft. The development of the X-37 was 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 International Space Station (ISS) is a large space station that was Assembly of the International Space Station, assembled and is maintained in low Earth orbit by a collaboration of five space agencies and their contractors: NASA (United ...
", according to a NASA fact sheet. The X-37 for NASA was to be powered by one Aerojet AR2-3 engine using storable propellants, providing thrust of . The human-rated AR2-3 engine had been used on the dual-power NF-104A astronaut training vehicle and was given a new flight certification for use on the X-37 with hydrogen peroxide/
JP-8 JP-8, or JP8 (for "Jet Propellant 8"), is a jet fuel, specified and used widely by the US military. It is specified by MIL-DTL-83133 and British Defence Standard 91-87, and similar to commercial aviation's Jet A-1, but with the addition of corros ...
propellants. This was reportedly changed to a hypergolic nitrogen-tetroxide/hydrazine propulsion system. The X-37 lands automatically upon returning from orbit and is the third reusable spacecraft to have such a capability, after the
Soviet The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...
'' Buran'' shuttle and the U.S. space shuttle, which had automatic landing capability by the mid-1990s, but never tested it. The X-37 is the smallest and lightest orbital spaceplane flown to date; it has a launch mass of around and is approximately one quarter the size of the Space Shuttle orbiter. On 13 April 2015, the Space Foundation awarded the X-37 team with the 2015 Space Achievement Award "for significantly advancing the state of the art for reusable spacecraft and on-orbit operations, with the design, development, test and orbital operation of the X-37B space flight vehicle over three missions totaling 1,367 days in space".


Operational history

The two operational X-37Bs have completed seven orbital missions; they have spent a combined 4,208.66 days (11.53 years) in space.


OTV-1

The first X-37B launched on its first mission–OTV-1/ USA-212–on an Atlas V rocket from Cape Canaveral SLC-41 on 22 April 2010 at 23:52 UTC. The spacecraft was placed into
low Earth orbit A low Earth orbit (LEO) is an geocentric orbit, orbit around Earth with a orbital period, period of 128 minutes or less (making at least 11.25 orbits per day) and an orbital eccentricity, eccentricity less than 0.25. Most of the artificial object ...
for testing. While the U.S. Air Force revealed few orbital details of the mission, a worldwide network of amateur astronomers claimed to have identified the spacecraft in orbit. On 22 May 2010, the spacecraft was in an inclination of 39.99°, circling the Earth once every 90 minutes on an orbit . OTV-1 reputedly passed over the same given spot on Earth every four days, and operated at an altitude that is typical for military surveillance satellites. Such an orbit is also common among civilian LEO satellites, and the spaceplane's altitude was the same as that of the ISS and most other crewed spacecraft. The U.S. Air Force announced a 3–6 December landing on 30 November 2010. As scheduled, the X-37B was de-orbited, reentered Earth's atmosphere, and landed successfully at
Vandenberg AFB Vandenberg Space Force Base , previously Vandenberg Air Force Base, is a United States Space Force Base in Santa Barbara County, California. Established in 1941, Vandenberg Space Force Base is a space launch base, launching spacecraft from the ...
on 3 December 2010, at 09:16 UTC, conducting the first US autonomous orbital landing onto a runway. This was the first such landing since the Soviet Buran shuttle in 1988. In all, OTV-1 spent in space. OTV-1 suffered a tire blowout during landing and sustained minor damage to its underside.


OTV-2

The second X-37B launched on its inaugural mission, designated OTV-2/
USA-226 OTV-2 (also known as USA-226) was the first flight of the second Boeing Boeing X-37, X-37B, an American unmanned robotic VTHL, vertical-takeoff, horizontal-landing spaceplane. It was launched aboard an Atlas V rocket from Cape Canaveral Air ...
, aboard an Atlas V rocket from Cape Canaveral SLC-41 on 5 March 2011 at 22:46 UTC. The mission was classified and described by the U.S. military as an effort to test new space technologies. On 29 November 2011, the U.S. Air Force announced that it would extend USA-226 beyond the 270-day baseline duration. In April 2012, General William L. Shelton of the Air Force Space Command declared the ongoing mission a "spectacular success". On 30 May 2012, the Air Force stated that the X-37B would land at Vandenberg AFB in June 2012. The spacecraft landed autonomously on 16 June 2012, having spent in space.


OTV-3

The third mission and second flight of the first X-37B, OTV-3 was originally scheduled to launch on 25 October 2012, but was postponed because of an engine issue with the Atlas V launch vehicle. It was successfully launched from Cape Canaveral SLC-41 on 11 December 2012 at 18:03 UTC. Once in orbit, the spacecraft was designated USA-240. Landing occurred at Vandenberg AFB on 17 October 2014 at 16:24 UTC, after a total time in orbit of .


OTV-4

The fourth X-37B mission, OTV-4, was codenamed AFSPC-5 and designated as USA-261 in orbit. It was the second flight of the second X-37B vehicle. The X-37B launched on an Atlas V rocket from Cape Canaveral SLC-41 on 20 May 2015 at 15:05 UTC. Objectives included a test of Aerojet Rocketdyne's XR-5A Hall-effect thruster in support of the Advanced Extremely High Frequency communications satellite program, and a NASA investigation on the performance of various materials in space for at least 200 days. The vehicle spent what was then a record-breaking in orbit before landing at
Kennedy Space Center The John F. Kennedy Space Center (KSC, originally known as the NASA Launch Operations Center), located on Merritt Island, Florida, is one of the NASA, National Aeronautics and Space Administration's (NASA) ten NASA facilities#List of field c ...
's
Shuttle Landing Facility The Shuttle Landing Facility (SLF), also known as Launch and Landing Facility (LLF) , is an airport located on Merritt Island, Florida, Merritt Island in Brevard County, Florida, Brevard County, Florida, United States. It is a part of the Kennedy ...
on 7 May 2017 at 11:47 UTC.


OTV-5

The fifth X-37B mission, designated USA-277 in orbit, was launched from Kennedy Space Center Launch Complex 39A on 7 September 2017 at 14:00 UTC, just before the arrival of
Hurricane Irma Hurricane Irma was an extremely powerful and devastating tropical cyclone that was the first Category 5 hurricane to strike the Leeward Islands on record, followed by Hurricane Maria, Maria two weeks later. At the time, it was considered ...
. The launch vehicle was a
Falcon 9 Falcon 9 is a Reusable launch system#Partial reusable launch systems, partially reusable, two-stage-to-orbit, medium-lift launch vehicle designed and manufactured in the United States by SpaceX. The first Falcon 9 launch was on June 4, 2010, an ...
rocket, and a number of small satellites also shared the ride. The spacecraft was inserted at a higher inclination orbit than previous missions, further expanding the X-37B's envelope. During the flight, the spacecraft modified its orbit using an on-board propulsion system. While the complete payload for OTV-5 is classified, the Air Force announced that one experiment flying is the Advanced Structurally Embedded Thermal Spreader II (ASETS-II), which measures the performance of an oscillating heat pipe. The mission was completed with the vehicle landing at the Shuttle Landing Facility on 27 October 2019 at 07:51 UTC.


OTV-6

The sixth X-37B mission (OTV-6), U.S. Space Force 7 (formerly known as AFSPC 7), launched on an Atlas V 501 rocket from Cape Canaveral SLC-41 on 17 May 2020 at 13:14:00 UTC. This mission is the first time the spaceplane has carried a service module, a ring attached to the rear of the vehicle for hosting multiple experiments. The mission hosts more experiments than prior X-37B flights, including two NASA experiments. One is a sample plate evaluating the reaction of select materials to conditions in space. The second studies the effect of ambient space radiation on seeds. A third experiment designed by the Naval Research Laboratory (NRL) transforms solar power into radio frequency microwave energy, then studies transmitting that energy to
Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...
. The X-37B remains a Department of the Air Force asset, but the newly established U.S. Space Force is responsible for the launch, on-orbit operations, and landing. The X-37B released a small, satellite named FalconSat-8 (USA-300) around 28 May 2020. Developed by United States Air Force Academy cadets in partnership with the
Air Force Research Laboratory The Air Force Research Laboratory (AFRL) is a scientific research and development detachment of the United States Air Force Air Force Materiel Command, Materiel Command dedicated to leading the discovery, development, and integration of direct- ...
(AFRL), the small satellite carries five experimental payloads. The spacecraft will test a novel electromagnetic propulsion system, low-weight antenna technology and a commercial reaction wheel to provide attitude control in orbit. According to the United States Air Force Academy, FalconSat-8's experiments include: * Magnetogradient Electrostatic Plasma Thruster (MEP) – Novel electromagnetic propulsion system * MetaMaterial Antenna (MMA) – Low size, weight, power antenna with
phased array In antenna (radio), antenna theory, a phased array usually means an electronically scanned array, a computer-controlled Antenna array, array of antennas which creates a radio beam, beam of radio waves that can be electronically steered to point ...
-like performance * Carbon nanotube experiment (CANOE) – RF cabling with carbon nanotube braiding flexed using shape-memory alloy * Attitude Control and Energy Storage (ACES) – Commercial reaction wheel modified into a flywheel for energy storage and release * SkyPad – Off-the-shelf cameras and GPUs integrated into low-SWAP (size, weight and power) package The mission was completed with the vehicle landing at the Shuttle Landing Facility on 12 November 2022 at 10:22 UTC.


OTV-7

The fourth flight of second X-37B and seventh overall X-37B mission was planned to be launched on SpaceX's Falcon Heavy on 12 December 2023. It was rescheduled for 28 December 2023, when it was successfully launched at 8:07 pm EST (01:07:00 UTC on December 29). The orbit is higher than any spaceplane, in a highly elliptical HEO orbit. In October 2024, OTV-7 was due to undertake aerobraking maneuvers to safely dispose of its service module. The mission ended on with landing at Vandenberg Space Force Base on 7 March 2025 at 07:22 UTC.


Variants


X-37A

The X-37A Approach and Landing Test Vehicle (ALTV) was an initial NASA version of the spacecraft used in drop glide tests in 2005 and 2006.


X-37B

The X-37B is a modified version of the NASA X-37A, built for the U.S. Air Force. Two have been built and used for multiple orbital missions.


X-37C

In 2011, Boeing announced plans for a scaled-up variant of the X-37B, referring to it as the X-37C. This spacecraft was planned to be between 165% and 180% of the size of the X-37B, allowing it to transport up to six astronauts inside a pressurized compartment housed in the cargo bay. The Atlas V was this variant's proposed launch vehicle. In this role, Boeing's X-37C could potentially compete with the corporation's CST-100 Starliner commercial space capsule. , with NASA selecting Starliner and SpaceX Crew Dragon, there has been no further announcement to develop X-37C.


Specifications (X-37B)


See also

* Boeing X-20 Dyna-Soar, the U.S. Air Force's original (1958–1963) spaceplane program, cancelled before craft was constructed * Dream Chaser, a lifting-body spaceplane being developed by Sierra Nevada Corporation * Orbital Sciences X-34, a proposed uncrewed suborbital reusable-rocket technology testbed * RLV Technology Demonstration Programme, Indian reusable spaceplane development project * Hermes (spacecraft), a proposed ESA spacecraft design * HOPE-X, a similar-sized vehicle of comparable role by
JAXA The is the Japanese national air and space agency. Through the merger of three previously independent organizations, JAXA was formed on 1 October 2003. JAXA is responsible for research, technology development and launch of satellites into o ...
(cancelled) * HYFLEX, a Japanese lifting body spaceplane in 1996, precursor to HOPE-X * Intermediate eXperimental Vehicle (IXV), an ESA designed experimental reentry vehicle * Shenlong (spacecraft), a Chinese reusable robotic spaceplane under development, first tested in 2011 (suborbital flight) * Chinese reusable experimental spacecraft, a reusable spaceplane under development * Skylon (spacecraft), a British reusable uncrewed spaceplane in development * Space Rider, a planned robotic spaceplane follow-up to IXV by ESA * Collier Trophy * List of USA satellites * List of X-planes


Explanatory notes


References


Sources

* *


Further reading

* *


External links


X-37 Orbital Test Vehicle fact sheet
from the U.S. Air Force
X-37B Orbital Test Vehicle page
at Boeing.com

at NASA.gov * {{DEFAULTSORT:X-37 X-37 Spaceplanes DARPA projects NASA programs Rocket-powered aircraft V-tail aircraft Mojave Air and Space Port Air Force Research Laboratory projects Military space program of the United States X-37, Boeing Spacecraft launched by Atlas rockets SpaceX military payloads Reusable spacecraft Secret space vehicles Equipment of the United States Space Force Uncrewed spacecraft Military vehicles introduced in the 2010s Collier Trophy recipients Tailless delta-wing aircraft Aircraft with retractable tricycle landing gear