Boeing X-37
Encyclopedia
The Boeing X-37 (also known as the Orbital Test Vehicle) is an American
unmanned
vertical-takeoff, horizontal-landing (VTHL) spaceplane
. The X-37 is operated by the United States Air Force
for orbital spaceflight missions intended to demonstrate reusable space technologies. It is a reusable robotic
spaceplane that is a 120% scaled derivative of the X-40A
.
The X-37 began as a NASA
project in 1999, then was transferred to the U.S. Department of Defense
in 2004. It had its first flight as a drop test on 7 April 2006, at Edwards Air Force Base
. The spaceplane's first orbital mission, USA-212 was launched on 22 April 2010 using an Atlas V rocket. Its return to Earth on 3 December 2010 was the first test of the vehicle's heat shield and hypersonic aerodynamic handling. A second X-37B was launched on 5 March 2011 with the mission designation USA-226
.
branch of Boeing's Phantom Works
. Over a four-year period NASA contributed $109 million, the US Air Force $16 million, and Boeing $67 million to the project. In late 2002 a new $301 million contract was awarded to Boeing in the framework of NASA's Space Launch Initiative
.
The X-37 was transferred from NASA to the Defense Advanced Research Projects Agency (DARPA) on 13 September 2004. The program has become a classified project
, although it is not known whether DARPA will maintain this status for the project. NASA's spaceflight program may be centered around the Crew Exploration Vehicle
, while DARPA will promote the X-37 as part of the independent space policy that the US Department of Defense
has pursued since the Challenger disaster
.
The X-37 was originally designed to be carried into orbit in the Space Shuttle
cargo bay, but underwent redesign for launch on a Delta IV or comparable rocket
after it was determined that a shuttle flight would be uneconomical. The X-37's aerodynamic design was derived from the Space Shuttle, hence the X-37 has a similar lift-to-drag ratio, and a lower cross range at high altitudes and Mach numbers than DARPA's Hypersonic Technology Vehicle.
As part of its Space Support mission goals, X-37 was designed to rendezvous with friendly satellites to refuel them, or to replace failed solar arrays using a robotic arm. Its payload could also support Space Control (Defensive Counter-Space, Offensive Counter-Space), Force Enhancement and Force Application. An early requirement for the spacecraft called for a delta-v
of 7000 mile per hour to change its orbit.
had no propulsion system. Instead of an operational vehicle's payload bay doors it had an enclosed and reinforced upper fuselage
structure to allow it to be mated with a mothership. In September 2004 DARPA announced that for its initial atmospheric drop tests the X-37 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, Mojave, California
. Through the second half of 2005, the X-37A underwent structural upgrades including reinforcement of the nose wheel
supports. Further captive-carry flight tests and the first drop test were expected mid-February 2006. The X-37's public debut was scheduled for its first free flight on 10 March 2006, but was canceled due to an Arctic storm. The next attempt at flight on 15 March 2006 was canceled due to high winds.
On 24 March 2006, the X-37 flew, but a data link failure prevented the free flight and the vehicle returned to the ground still attached to its White Knight carrier. On 7 April 2006, the X-37 made its first free glide flight. During landing, the vehicle overran the runway and it sustained minor damage.
Following an extended downtime while the vehicle was repaired, the program moved from Mojave to Air Force Plant 42
(KPMD) in Palmdale, California
for the remainder of the flight test program. White Knight continued to be based at Mojave, but would ferry over to Plant 42 when flights were scheduled. Five additional flights were performed, two of which resulted in X-37 releases with successful landing
s. These free flights occurred on 18 August 2006 and 26 September 2006.
On 17 November 2006 the U.S. Air Force
announced it would develop the X-37B from the NASA X-37A. The Air Force version is designated X-37B Orbital Test Vehicle (OTV). The OTV program was built on earlier industry and government efforts by DARPA, NASA and the Air Force. The X-37B effort is led by the Air Force Rapid Capabilities Office, in partnership with NASA and the Air Force Research Laboratory
. Boeing is the prime contractor for the OTV program. The X-37B can remain in orbit for up to 270 days at a time.
The Secretary of the Air Force stated the OTV program will 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 following the Columbia accident
, it was transferred to a Delta II 7920. It was subsequently transferred to a shrouded configuration on the Atlas V
following concerns over the unshrouded spacecraft's aerodynamic
properties during launch. Following their mission, X-37B spacecraft land on a runway at Vandenberg Air Force Base
, California, with Edwards Air Force Base
as an alternate site.
Manufacturing on the second X-37B, OTV-2 was underway in 2010; it was completed and was first launched in March 2011.
spaceplane. It is a 20% larger derivative of X-40. The OTV has a length of over 29 feet (8.8 m) and features two angled tail fins. The spaceplane's payload bay is available for experiments and other space payloads. It features thermal protection systems that are improved from previous generations of spacecraft. The thermal protection system uses improved silica ceramic tiles.
The X-37 is expected to operate in a velocity range of up to Mach 25
on reentry. Among the technologies to be demonstrated with the X-37 are improved thermal protection systems, avionics
, the autonomous guidance system
and an advanced airframe
. The vehicle is powered by a Rocketdyne
AR2-3 engine. The AR2-3 was the human-rated
rocket powerplant for 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
propellants. The X-37B now uses a hydrazine
monopropellant rocket
.
Because the X-37 is a robotic vehicle, it is capable of landing automatically upon returning from orbit. It is the second reusable spacecraft to have such a capability, the first being the Soviet Buran.
rocket at Cape Canaveral Air Force Station
, Florida on 22 April 2010, at 23:58 GMT. The spacecraft was placed into low Earth orbit
for testing.
While the U.S. Air Force revealed few orbital details after the first X-37B was successfully placed in orbit due to the secretive nature of the mission, amateur astronomers claimed to have identified the experimental spacecraft in orbit and shared their findings. A worldwide network of amateur astronomers reported that on 22 May it was in an inclination of 39.99 degrees, circling the Earth once every 90 minutes on an orbit 401 by. The amateur sky watchers reported the spacecraft's track went over North Korea
, Afghanistan
, and other trouble spots. They reported that the spacecraft passed over the same given spot on Earth every four days, and operated at an altitude of 255 miles (410.4 km), which is typical for a military surveillance satellite.
The U.S. Air Force announced on 30 November 2010 that the X-37 would return for a landing during the 3–6 December timeframe. As scheduled, OTV-1 de-orbited, reentered Earth's atmosphere, and landed at Vandenberg AFB on 3 December 2010, at 1:16 PST (09:16 UTC), making the first U.S. autonomous
landing
from space onto a runway. The X-37B had a tire blowout during landing and sustained minor damage to its underside.
A second X-37B mission, designated USA-226
, was launched aboard an Atlas V rocket, on 5 March 2011. The mission was classified and described by the US military as to test out new space technologies. On 29 November 2011, the Air Force announced it would extend the mission of USA-226 beyond the (} baseline design duration.
newspaper wrote that the X-37B program raised concerns about an arms race in space. The Xinhua News Agency
took a more moderate tone in questioning if the secretive program might lead to weapons in space. Tom Burghardt wrote for Spacedaily.com
that the X-37B could be used as a spy satellite
or to deliver weapons from space. The Pentagon
has denied claims that the X-37B's mission supports the development of space-based weapons.
Evolved Expendable Launch Vehicle.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
unmanned
Unmanned aerial vehicle
An unmanned aerial vehicle , also known as a unmanned aircraft system , remotely piloted aircraft or unmanned aircraft, is a machine which functions either by the remote control of a navigator or pilot or autonomously, that is, as a self-directing entity...
vertical-takeoff, horizontal-landing (VTHL) spaceplane
Spaceplane
A spaceplane is a vehicle that operates as an aircraft in Earth's atmosphere, as well as a spacecraft when it is in space. It combines features of an aircraft and a spacecraft, which can be thought of as an aircraft that can endure and maneuver in the vacuum of space or likewise a spacecraft that...
. The X-37 is operated by the United States Air Force
United States Air Force
The United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...
for orbital spaceflight missions intended to demonstrate reusable space technologies. It is a reusable robotic
Robotic spacecraft
A robotic spacecraft is a spacecraft with no humans on board, that is usually under telerobotic control. A robotic spacecraft designed to make scientific research measurements is often called a space probe. Many space missions are more suited to telerobotic rather than crewed operation, due to...
spaceplane that is a 120% scaled derivative of the X-40A
Boeing X-40
-See also:-External links:* * * * *...
.
The X-37 began as a NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
project in 1999, then was transferred to the U.S. Department of Defense
United States Department of Defense
The United States Department of Defense is the U.S...
in 2004. It had its first flight as a drop test on 7 April 2006, at Edwards Air Force Base
Edwards Air Force Base
Edwards Air Force Base is a United States Air Force base located on the border of Kern County, Los Angeles County, and San Bernardino County, California, in the Antelope Valley. It is southwest of the central business district of North Edwards, California and due east of Rosamond.It is named in...
. The spaceplane's first orbital mission, USA-212 was launched on 22 April 2010 using an Atlas V rocket. Its return to Earth on 3 December 2010 was the first test of the vehicle's heat shield and hypersonic aerodynamic handling. A second X-37B was launched on 5 March 2011 with the mission designation USA-226
USA-226
USA-226 is the first flight of the second Boeing X-37B, the Orbital Test Vehicle 2 , an American unmanned robotic vertical-takeoff, horizontal-landing spaceplane. It was launched aboard an Atlas V rocket from Cape Canaveral on 2011, and is currently being operated in low Earth orbit...
.
Origins
In 1999, NASA selected Boeing Integrated Defense Systems to design and develop the vehicle, built by the CaliforniaCalifornia
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
branch of Boeing's Phantom Works
Boeing Phantom Works
The Phantom Works division is the advanced prototyping arm of the Defense and Security side of The Boeing Company. Its primary focus is developing advanced military products and technologies, many of them highly classified, and has produced breakthroughs in defense, space and security.Founded by...
. Over a four-year period NASA contributed $109 million, the US Air Force $16 million, and Boeing $67 million to the project. In late 2002 a new $301 million contract was awarded to Boeing in the framework of NASA's Space Launch Initiative
Space Launch Initiative
The Space Launch Initiative was a NASA and U.S. Department of Defense joint research and technology project to determine the requirements to meet all the nation’s hypersonics, space launch and space technology needs...
.
The X-37 was transferred from NASA to the Defense Advanced Research Projects Agency (DARPA) on 13 September 2004. The program has become a classified project
Classified information in the United States
The United States government classification system is currently established under Executive Order 13526, the latest in a long series of executive orders on the topic. Issued by President Barack Obama in 2009, Executive Order 13526 replaced earlier executive orders on the topic and modified the...
, although it is not known whether DARPA will maintain this status for the project. NASA's spaceflight program may be centered around the Crew Exploration Vehicle
Crew Exploration Vehicle
The Crew Exploration Vehicle was the conceptual component of the U.S. NASA Vision for Space Exploration that later became known as the Orion spacecraft...
, while DARPA will promote the X-37 as part of the independent space policy that the US Department of Defense
United States Department of Defense
The United States Department of Defense is the U.S...
has pursued since the Challenger disaster
Space Shuttle Challenger disaster
The Space Shuttle Challenger disaster occurred on January 28, 1986, when Space Shuttle Challenger broke apart 73 seconds into its flight, leading to the deaths of its seven crew members. The spacecraft disintegrated over the Atlantic Ocean, off the coast of central Florida at 11:38 am EST...
.
The X-37 was originally designed to be carried into orbit in the Space Shuttle
Space Shuttle
The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...
cargo bay, but underwent redesign for launch on a Delta IV or comparable rocket
Launch vehicle
In spaceflight, a launch vehicle or carrier rocket is a rocket used to carry a payload from the Earth's surface into outer space. A launch system includes the launch vehicle, the launch pad and other infrastructure....
after it was determined that a shuttle flight would be uneconomical. The X-37's aerodynamic design was derived from the Space Shuttle, hence the X-37 has a similar lift-to-drag ratio, and a lower cross range at high altitudes and Mach numbers than DARPA's Hypersonic Technology Vehicle.
As part of its Space Support mission goals, X-37 was designed to rendezvous with friendly satellites to refuel them, or to replace failed solar arrays using a robotic arm. Its payload could also support Space Control (Defensive Counter-Space, Offensive Counter-Space), Force Enhancement and Force Application. An early requirement for the spacecraft called for a delta-v
Delta-v
In astrodynamics a Δv or delta-v is a scalar which takes units of speed. It is a measure of the amount of "effort" that is needed to change from one trajectory to another by making an orbital maneuver....
of 7000 mile per hour to change its orbit.
Glide tests
The vehicle that was used as an atmospheric drop test gliderGlider aircraft
Glider aircraft are heavier-than-air craft that are supported in flight by the dynamic reaction of the air against their lifting surfaces, and whose free flight does not depend on an engine. Mostly these types of aircraft are intended for routine operation without engines, though engine failure can...
had no propulsion system. Instead of an operational vehicle's payload bay doors it had an enclosed and reinforced upper fuselage
Fuselage
The fuselage is an aircraft's main body section that holds crew and passengers or cargo. In single-engine aircraft it will usually contain an engine, although in some amphibious aircraft the single engine is mounted on a pylon attached to the fuselage which in turn is used as a floating hull...
structure to allow it to be mated with a mothership. In September 2004 DARPA announced that for its initial atmospheric drop tests the X-37 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, Mojave, California
Mojave, California
Mojave is a census-designated place in Kern County, California, United States. Mojave is located east of Bakersfield, at an elevation of 2762 feet...
. Through the second half of 2005, the X-37A underwent structural upgrades including reinforcement of the nose wheel
Undercarriage
The undercarriage or landing gear in aviation, is the structure that supports an aircraft on the ground and allows it to taxi, takeoff and land...
supports. Further captive-carry flight tests and the first drop test were expected mid-February 2006. The X-37's public debut was scheduled for its first free flight on 10 March 2006, but was canceled due to an Arctic storm. The next attempt at flight on 15 March 2006 was canceled due to high winds.
On 24 March 2006, the X-37 flew, but a data link failure prevented the free flight and the vehicle returned to the ground still attached to its White Knight carrier. On 7 April 2006, the X-37 made its first free glide flight. During landing, the vehicle overran the runway and it sustained minor damage.
Following an extended downtime while the vehicle was repaired, the program moved from Mojave to Air Force Plant 42
Plant 42
Air Force Plant 42 is a federally owned military aerospace facility under the control of the Air Force Material Command in Palmdale, California...
(KPMD) in Palmdale, California
Palmdale, California
Palmdale is a city located in the center of northern Los Angeles County, California, United States.Palmdale was the first community within the Antelope Valley to incorporate as a city on August 24, 1962; 47 years later, voters approved creating a charter city in November, 2009. Palmdale is...
for the remainder of the flight test program. White Knight continued to be based at Mojave, but would ferry over to Plant 42 when flights were scheduled. Five additional flights were performed, two of which resulted in X-37 releases with successful landing
Landing
thumb|A [[Mute Swan]] alighting. Note the ruffled feathers on top of the wings indicate that the swan is flying at the [[Stall |stall]]ing speed...
s. These free flights occurred on 18 August 2006 and 26 September 2006.
X-37B Orbital Test Vehicle
United States Air Force
The United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...
announced it would develop the X-37B from the NASA X-37A. The Air Force version is designated X-37B Orbital Test Vehicle (OTV). The OTV program was built on earlier industry and government efforts by DARPA, NASA and the Air Force. The X-37B effort is led by the Air Force Rapid Capabilities Office, in partnership with NASA and the Air Force Research Laboratory
Air Force Research Laboratory
The Air Force Research Laboratory is a scientific research organization operated by the United States Air Force Materiel Command dedicated to leading the discovery, development, and integration of affordable aerospace warfighting technologies; planning and executing the Air Force science and...
. Boeing is the prime contractor for the OTV program. The X-37B can remain in orbit for up to 270 days at a time.
The Secretary of the Air Force stated the OTV program will 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 following the Columbia accident
Space Shuttle Columbia disaster
The Space Shuttle Columbia disaster occurred on February 1, 2003, when shortly before it was scheduled to conclude its 28th mission, STS-107, the Space Shuttle Columbia disintegrated over Texas and Louisiana during re-entry into the Earth's atmosphere, resulting in the death of all seven crew members...
, it was transferred to a Delta II 7920. It was subsequently transferred to a shrouded configuration on the Atlas V
Atlas V
Atlas V is an active expendable launch system in the Atlas rocket family. Atlas V was formerly operated by Lockheed Martin, and is now operated by the Lockheed Martin-Boeing joint venture United Launch Alliance...
following concerns over the unshrouded spacecraft's aerodynamic
Aerodynamics
Aerodynamics is a branch of dynamics concerned with studying the motion of air, particularly when it interacts with a moving object. Aerodynamics is a subfield of fluid dynamics and gas dynamics, with much theory shared between them. Aerodynamics is often used synonymously with gas dynamics, with...
properties during launch. Following their mission, X-37B spacecraft land on a runway at Vandenberg Air Force Base
Vandenberg Air Force Base
Vandenberg Air Force Base is a United States Air Force Base, located approximately northwest of Lompoc, California. It is under the jurisdiction of the 30th Space Wing, Air Force Space Command ....
, California, with Edwards Air Force Base
Edwards Air Force Base
Edwards Air Force Base is a United States Air Force base located on the border of Kern County, Los Angeles County, and San Bernardino County, California, in the Antelope Valley. It is southwest of the central business district of North Edwards, California and due east of Rosamond.It is named in...
as an alternate site.
Manufacturing on the second X-37B, OTV-2 was underway in 2010; it was completed and was first launched in March 2011.
Design
The X-37 Orbital Test Vehicle is a reusable roboticRobotic spacecraft
A robotic spacecraft is a spacecraft with no humans on board, that is usually under telerobotic control. A robotic spacecraft designed to make scientific research measurements is often called a space probe. Many space missions are more suited to telerobotic rather than crewed operation, due to...
spaceplane. It is a 20% larger derivative of X-40. The OTV has a length of over 29 feet (8.8 m) and features two angled tail fins. The spaceplane's payload bay is available for experiments and other space payloads. It features thermal protection systems that are improved from previous generations of spacecraft. The thermal protection system uses improved silica ceramic tiles.
The X-37 is expected to operate in a velocity range of up to Mach 25
Mach number
Mach number is the speed of an object moving through air, or any other fluid substance, divided by the speed of sound as it is in that substance for its particular physical conditions, including those of temperature and pressure...
on reentry. Among the technologies to be demonstrated with the X-37 are improved thermal protection systems, avionics
Avionics
Avionics are electronic systems used on aircraft, artificial satellites and spacecraft.Avionic systems include communications, navigation, the display and management of multiple systems and the hundreds of systems that are fitted to aircraft to meet individual roles...
, the autonomous guidance system
Guidance system
A guidance system is a device or group of devices used to navigate a ship, aircraft, missile, rocket, satellite, or other craft. Typically, this refers to a system that navigates without direct or continuous human control...
and an advanced airframe
Airframe
The airframe of an aircraft is its mechanical structure. It is typically considered to include fuselage, wings and undercarriage and exclude the propulsion system...
. The vehicle is powered by a Rocketdyne
Pratt & Whitney Rocketdyne
Pratt & Whitney Rocketdyne is a United States company that designs and produces rocket engines that use liquid propellants. Pratt & Whitney Rocketdyne, headquartered in Canoga Park, California, is a division of Pratt & Whitney, itself a wholly owned subsidiary of United Technologies Corporation...
AR2-3 engine. The AR2-3 was the human-rated
Human-rating certification
Human-rated or man-rated are terms used to describe the certification of a spacecraft, launch vehicleor airplaneas worthy of transporting humans. NASA and the U.S. GAO now uses "Human-rating" when describing requirements for these systems...
rocket powerplant for the dual-power NF-104A
Lockheed NF-104A
The Lockheed NF-104A was an American mixed power, high-performance, supersonic aerospace trainer that served as a low cost astronaut training vehicle for the X-15 and projected X-20 Dyna-Soar programs....
astronaut training vehicle and was given a new flight certification for use on the X-37 with hydrogen peroxide
Hydrogen peroxide
Hydrogen peroxide is the simplest peroxide and an oxidizer. Hydrogen peroxide is a clear liquid, slightly more viscous than water. In dilute solution, it appears colorless. With its oxidizing properties, hydrogen peroxide is often used as a bleach or cleaning agent...
/JP-8
JP-8
JP-8, or JP8 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....
propellants. The X-37B now uses a hydrazine
Hydrazine
Hydrazine is an inorganic compound with the formula N2H4. It is a colourless flammable liquid with an ammonia-like odor. Hydrazine is highly toxic and dangerously unstable unless handled in solution. Approximately 260,000 tons are manufactured annually...
monopropellant rocket
Monopropellant rocket
A monopropellant rocket is a rocket that uses a single chemical as its propellant.-Chemical-reaction monopropellant rockets:...
.
Because the X-37 is a robotic vehicle, it is capable of landing automatically upon returning from orbit. It is the second reusable spacecraft to have such a capability, the first being the Soviet Buran.
Operational history
The first orbital flight of OTV-1, the first X-37B, with a mission name of USA-212, was launched on an Atlas VAtlas V
Atlas V is an active expendable launch system in the Atlas rocket family. Atlas V was formerly operated by Lockheed Martin, and is now operated by the Lockheed Martin-Boeing joint venture United Launch Alliance...
rocket at Cape Canaveral Air Force Station
Cape Canaveral Air Force Station
Cape Canaveral Air Force Station is an installation of the United States Air Force Space Command's 45th Space Wing, headquartered at nearby Patrick Air Force Base. Located on Cape Canaveral in the state of Florida, CCAFS is the primary launch head of America's Eastern Range with four launch pads...
, Florida on 22 April 2010, at 23:58 GMT. The spacecraft was placed into low Earth orbit
Low Earth orbit
A low Earth orbit is generally defined as an orbit within the locus extending from the Earth’s surface up to an altitude of 2,000 km...
for testing.
While the U.S. Air Force revealed few orbital details after the first X-37B was successfully placed in orbit due to the secretive nature of the mission, amateur astronomers claimed to have identified the experimental spacecraft in orbit and shared their findings. A worldwide network of amateur astronomers reported that on 22 May it was in an inclination of 39.99 degrees, circling the Earth once every 90 minutes on an orbit 401 by. The amateur sky watchers reported the spacecraft's track went over North Korea
North Korea
The Democratic People’s Republic of Korea , , is a country in East Asia, occupying the northern half of the Korean Peninsula. Its capital and largest city is Pyongyang. The Korean Demilitarized Zone serves as the buffer zone between North Korea and South Korea...
, Afghanistan
Afghanistan
Afghanistan , officially the Islamic Republic of Afghanistan, is a landlocked country located in the centre of Asia, forming South Asia, Central Asia and the Middle East. With a population of about 29 million, it has an area of , making it the 42nd most populous and 41st largest nation in the world...
, and other trouble spots. They reported that the spacecraft passed over the same given spot on Earth every four days, and operated at an altitude of 255 miles (410.4 km), which is typical for a military surveillance satellite.
The U.S. Air Force announced on 30 November 2010 that the X-37 would return for a landing during the 3–6 December timeframe. As scheduled, OTV-1 de-orbited, reentered Earth's atmosphere, and landed at Vandenberg AFB on 3 December 2010, at 1:16 PST (09:16 UTC), making the first U.S. autonomous
Autonomous robot
Autonomous robots are robots that can perform desired tasks in unstructured environments without continuous human guidance. Many kinds of robots have some degree of autonomy. Different robots can be autonomous in different ways...
landing
Landing
thumb|A [[Mute Swan]] alighting. Note the ruffled feathers on top of the wings indicate that the swan is flying at the [[Stall |stall]]ing speed...
from space onto a runway. The X-37B had a tire blowout during landing and sustained minor damage to its underside.
A second X-37B mission, designated USA-226
USA-226
USA-226 is the first flight of the second Boeing X-37B, the Orbital Test Vehicle 2 , an American unmanned robotic vertical-takeoff, horizontal-landing spaceplane. It was launched aboard an Atlas V rocket from Cape Canaveral on 2011, and is currently being operated in low Earth orbit...
, was launched aboard an Atlas V rocket, on 5 March 2011. The mission was classified and described by the US military as to test out new space technologies. On 29 November 2011, the Air Force announced it would extend the mission of USA-226 beyond the (} baseline design duration.
Controversy
In April 2010, the China DailyChina Daily
The China Daily is an English language daily newspaper published in the People's Republic of China.- Overview :China Daily was established in June 1981 and has the widest print circulation of any English-language newspaper in the country...
newspaper wrote that the X-37B program raised concerns about an arms race in space. The Xinhua News Agency
Xinhua News Agency
The Xinhua News Agency is the official press agency of the government of the People's Republic of China and the biggest center for collecting information and press conferences in the PRC. It is the largest news agency in the PRC, ahead of the China News Service...
took a more moderate tone in questioning if the secretive program might lead to weapons in space. Tom Burghardt wrote for Spacedaily.com
Spacedaily.com
SpaceDaily.com is a popular online news site for space industry professionals.-History:SpaceDaily.com was founded in 1995 in Tokyo by Simon Mansfield with an initial focus on Japanese space news and planetary image archives. In 1997 the website grew to include global space coverage building from...
that the X-37B could be used as a spy satellite
Spy satellite
A spy satellite is an Earth observation satellite or communications satellite deployed for military or intelligence applications....
or to deliver weapons from space. The Pentagon
The Pentagon
The Pentagon is the headquarters of the United States Department of Defense, located in Arlington County, Virginia. As a symbol of the U.S. military, "the Pentagon" is often used metonymically to refer to the Department of Defense rather than the building itself.Designed by the American architect...
has denied claims that the X-37B's mission supports the development of space-based weapons.
X-37A
The X-37A was the initial version for NASA; the X-37A Approach and Landing Test Vehicle (ALTV) was used in drop glide tests.X-37C
In 2011, Boeing announced plans for a scaled up variant of the X-37B, referring to the spacecraft as the X-37C. The size of the X-37C would be approximately 165 to 180 percent of the X-37B and could transport up to six astronauts inside a pressurized compartment housed in the cargo bay. The proposed launch vehicle is the Atlas VAtlas V
Atlas V is an active expendable launch system in the Atlas rocket family. Atlas V was formerly operated by Lockheed Martin, and is now operated by the Lockheed Martin-Boeing joint venture United Launch Alliance...
Evolved Expendable Launch Vehicle.