.

The National Aeronautics and Space Administration (NASA) is the agency of the United States Federal Government responsible for the civilian space program as well as aeronautics and aerospace research.

President Dwight D. Eisenhower established NASA in 1958[5] with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA's predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.[6][7]

Since that time, most US space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle, the Space Launch System and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches.

NASA science is focused on better understanding Earth through the Earth Observing System,[8] advancing heliophysics through the efforts of the Science Mission Directorate's Heliophysics Research Program,[9] exploring bodies throughout the Solar System with advanced robotic spacecraft missions such as New Horizons,[10] and researching astrophysics topics, such as the Big Bang, through the Great Observatories and associated programs.[11] NASA shares data with various national and international organizations such as from the Greenhouse Gases Observing Satellite.

Creation
Main article: Creation of NASA
Dr. William H. Pickering, (center) JPL Director, President John F. Kennedy, (right). NASA Administrator James E. Webb (background) discussing the Mariner program, with a model presented.

From 1946, the National Advisory Committee for Aeronautics (NACA) had been experimenting with rocket planes such as the supersonic Bell X-1.[12] In the early 1950s, there was challenge to launch an artificial satellite for the International Geophysical Year (1957–58). An effort for this was the American Project Vanguard. After the Soviet launch of the world's first artificial satellite (Sputnik 1) on October 4, 1957, the attention of the United States turned toward its own fledgling space efforts. The US Congress, alarmed by the perceived threat to national security and technological leadership (known as the "Sputnik crisis"), urged immediate and swift action; President Dwight D. Eisenhower and his advisers counseled more deliberate measures. This led to an agreement that a new federal agency mainly based on NACA was needed to conduct all non-military activity in space. The Advanced Research Projects Agency (ARPA) was created in February 1958 to develop space technology for military application.[13]

On July 29, 1958, Eisenhower signed the National Aeronautics and Space Act, establishing NASA. When it began operations on October 1, 1958, NASA absorbed the 46-year-old NACA intact; its 8,000 employees, an annual budget of US$100 million, three major research laboratories (Langley Aeronautical Laboratory, Ames Aeronautical Laboratory, and Lewis Flight Propulsion Laboratory) and two small test facilities.[14] A NASA seal was approved by President Eisenhower in 1959.[15] Elements of the Army Ballistic Missile Agency and the United States Naval Research Laboratory were incorporated into NASA. A significant contributor to NASA's entry into the Space Race with the Soviet Union was the technology from the German rocket program led by Wernher von Braun, who was now working for the Army Ballistic Missile Agency (ABMA), which in turn incorporated the technology of American scientist Robert Goddard's earlier works.[16] Earlier research efforts within the US Air Force[14] and many of ARPA's early space programs were also transferred to NASA.[17] In December 1958, NASA gained control of the Jet Propulsion Laboratory, a contractor facility operated by the California Institute of Technology.[14]
Space flight programs
At launch control for the May 28, 1964, Saturn I SA-6 launch. Wernher von Braun is at center.
Main article: List of NASA missions

NASA has conducted many manned and unmanned spaceflight programs throughout its history. Unmanned programs launched the first American artificial satellites into Earth orbit for scientific and communications purposes, and sent scientific probes to explore the planets of the solar system, starting with Venus and Mars, and including "grand tours" of the outer planets. Manned programs sent the first Americans into low Earth orbit (LEO), won the Space Race with the Soviet Union by landing twelve men on the Moon from 1969 to 1972 in the Apollo program, developed a semi-reusable LEO Space Shuttle, and developed LEO space station capability by itself and with the cooperation of several other nations including post-Soviet Russia. Some missions include both manned and unmanned aspects, such as the Galileo probe, which was deployed by astronauts in Earth orbit before being sent unmanned to Jupiter.
Manned programs

The experimental rocket-powered aircraft programs started by NACA were extended by NASA as support for manned spaceflight. This was followed by a one-man space capsule program, and in turn by a two-man capsule program. Reacting to loss of national prestige and security fears caused by early leads in space exploration by the Soviet Union, in 1961 President John F. Kennedy proposed the ambitious goal "of landing a man on the Moon by the end of [the 1960s], and returning him safely to the Earth." This goal was met in 1969 by the Apollo program, and NASA planned even more ambitious activities leading to a manned mission to Mars. However, reduction of the perceived threat and changing political priorities almost immediately caused the termination of most of these plans. NASA turned its attention to an Apollo-derived temporary space laboratory, and a semi-reusable Earth orbital shuttle. In the 1990s, funding was approved for NASA to develop a permanent Earth orbital space station in cooperation with the international community, which now included the former rival, post-Soviet Russia. To date, NASA has launched a total of 166 manned space missions on rockets, and thirteen X-15 rocket flights above the USAF definition of spaceflight altitude, 260,000 feet (80 km).[18]
X-15 rocket plane (1959–68)
Main article: North American X-15

The X-15 was an NACA experimental rocket-powered hypersonic research aircraft, developed in conjunction with the US Air Force and Navy. The design featured a slender fuselage with fairings along the side containing fuel and early computerized control systems.[19] Requests for proposal were issued on December 30, 1954 for the airframe, and February 4, 1955 for the rocket engine. The airframe contract was awarded to North American Aviation in November 1955, and the XLR30 engine contract was awarded to Reaction Motors in 1956, and three planes were built. The X-15 was drop-launched from the wing of one of two NASA Boeing B-52 Stratofortresses, NB52A tail number 52-003, and NB52B, tail number 52-008 (known as the Balls 8). Release took place at an altitude of about 45,000 feet (14 km) and a speed of about 500 miles per hour (805 km/h).

Twelve pilots were selected for the program from the Air Force, Navy, and NACA (later NASA). A total of 199 flights were made between 1959 and 1968, resulting in the official world record for the highest speed ever reached by a manned powered aircraft (current as of 2014), and a maximum speed of Mach 6.72, 4,519 miles per hour (7,273 km/h).[20] The altitude record for X-15 was 354,200 feet (107.96 km).[21] Eight of the pilots were awarded Air Force astronaut wings for flying above 260,000 feet (80 km), and two flights by Joseph A. Walker exceeded 100 kilometers (330,000 ft), qualifying as spaceflight according to the International Aeronautical Federation. The X-15 program employed mechanical techniques used in the later manned spaceflight programs, including reaction control system jets for controlling the orientation of a spacecraft, space suits, and horizon definition for navigation.[21] The reentry and landing data collected were valuable to NASA for designing the Space Shuttle.[19]
Project Mercury (1959–63)
Main article: Project Mercury
Friendship 7, first US manned orbital spaceflight
Launch of Mercury-Atlas
Mercury-Atlas 6 launch on February 20, 1962
Still frame of John Glenn in orbit from camera inside Friendship 7

Shortly after the Space Race began, an early objective was to get a person into Earth orbit as soon as possible, therefore the simplest spacecraft that could be launched by existing rockets was favored. The US Air Force's Man in Space Soonest program considered many manned spacecraft designs, ranging from rocket planes like the X-15, to small ballistic space capsules.[22] By 1958, the space plane concepts were eliminated in favor of the ballistic capsule.[23]

When NASA was created that same year, the Air Force program was transferred to it and renamed Project Mercury. The first seven astronauts were selected among candidates from the Navy, Air Force and Marine test pilot programs. On May 5, 1961, astronaut Alan Shepard became the first American in space aboard Freedom 7, launched by a Redstone booster on a 15-minute ballistic (suborbital) flight.[24] John Glenn became the first American to be launched into orbit by an Atlas launch vehicle on February 20, 1962 aboard Friendship 7.[25] Glenn completed three orbits, after which three more orbital flights were made, culminating in L. Gordon Cooper's 22-orbit flight Faith 7, May 15–16, 1963.[26]

The Soviet Union (USSR) competed with its own single-pilot spacecraft, Vostok. They sent the first man in space, by launching cosmonaut Yuri Gagarin into a single Earth orbit aboard Vostok 1 in April 1961, one month before Shepard's flight.[27] In August 1962, they achieved an almost four-day record flight with Andriyan Nikolayev aboard Vostok 3, and also conducted a concurrent Vostok 4 mission carrying Pavel Popovich.
Project Gemini (1961–66)
Ed White performs the first US spacewalk in 1965 during the Gemini 4.
Main article: Project Gemini

Based on studies to grow the Mercury spacecraft capabilities to long-duration flights, developing space rendezvous techniques, and precision Earth landing, Project Gemini was started as a two-man program in 1962 to overcome the Soviets' lead and to support the Apollo manned lunar landing program, adding extravehicular activity (EVA) and rendezvous and docking to its objectives. The first manned Gemini flight, Gemini 3, was flown by Gus Grissom and John Young on March 23, 1965.[28] Nine missions followed in 1965 and 1966, demonstrating an endurance mission of nearly fourteen days, rendezvous, docking, and practical EVA, and gathering medical data on the effects of weightlessness on humans.[29][30]

Under the direction of Soviet Premier Nikita Khrushchev, the USSR competed with Gemini by converting their Vostok spacecraft into a two- or three-man Voskhod. They succeeded in launching two manned flights before Gemini's first flight, achieving a three-cosmonaut flight in 1963 and the first EVA in 1964. After this, the program was canceled, and Gemini caught up while spacecraft designer Sergei Korolev developed the Soyuz spacecraft, their answer to Apollo.
Spacecraft and launch vehicle comparison of Apollo, Gemini and Mercury. The Saturn IB and Mercury-Redstone launch vehicles are left out.
Project Apollo (1961–72)
Main article: Apollo program

The U.S public's perception of the Soviet lead in putting the first man in space, motivated President John F. Kennedy to ask the Congress on May 25, 1961 to commit the federal government to a program to land a man on the Moon by the end of the 1960s, which effectively launched the Apollo program.[31]

Apollo was one of the most expensive American scientific programs ever. It cost more than $20 billion in 1960s dollars[32] or an estimated $206 billion in present-day US dollars.[33] (In comparison, the Manhattan Project cost roughly $26.3 billion, accounting for inflation.)[33][34] It used the Saturn rockets as launch vehicles, which were far bigger than the rockets built for previous projects.[35] The spacecraft was also bigger; it had two main parts, the combined command and service module (CSM) and the lunar landing module (LM). The LM was to be left on the Moon and only the command module (CM) containing the three astronauts would eventually return to Earth.
Buzz Aldrin on the Moon, 1969

The second manned mission, Apollo 8, brought astronauts for the first time in a flight around the Moon in December 1968.[36] Shortly before, the Soviets had sent an unmanned spacecraft around the Moon.[37] On the next two missions docking maneuvers that were needed for the Moon landing were practiced[38][39] and then finally the Moon landing was made on the Apollo 11 mission in July 1969.[40]

The first person to stand on the Moon was Neil Armstrong, who was followed by Buzz Aldrin, while Michael Collins orbited above. Five subsequent Apollo missions also landed astronauts on the Moon, the last in December 1972. Throughout these six Apollo spaceflights, twelve men walked on the Moon. These missions returned a wealth of scientific data and 381.7 kilograms (842 lb) of lunar samples. Topics covered by experiments performed included soil mechanics, meteoroids, seismology, heat flow, lunar ranging, magnetic fields, and solar wind.[41] The Moon landing marked the end of the space race; and as a gesture, Armstrong mentioned mankind when he stepped down on the Moon.[42]
Apollo 17's lunar roving vehicle, 1972

Apollo set major milestones in human spaceflight. It stands alone in sending manned missions beyond low Earth orbit, and landing humans on another celestial body.[43] Apollo 8 was the first manned spacecraft to orbit another celestial body, while Apollo 17 marked the last moonwalk and the last manned mission beyond low Earth orbit to date. The program spurred advances in many areas of technology peripheral to rocketry and manned spaceflight, including avionics, telecommunications, and computers. Apollo sparked interest in many fields of engineering and left many physical facilities and machines developed for the program as landmarks. Many objects and artifacts from the program are on display at various locations throughout the world, notably at the Smithsonian's Air and Space Museums.
Skylab (1965–79)
Main article: Skylab
Skylab space station, 1974

Skylab was the United States' first and only independently built space station.[44] Conceived in 1965 as a workshop to be constructed in space from a spent Saturn IB upper stage, the 169,950 lb (77,088 kg) station was constructed on Earth and launched on May 14, 1973 atop the first two stages of a Saturn V, into a 235-nautical-mile (435 km) orbit inclined at 50° to the equator. Damaged during launch by the loss of its thermal protection and one electricity-generating solar panel, it was repaired to functionality by its first crew. It was occupied for a total of 171 days by 3 successive crews in 1973 and 1974.[44] It included a laboratory for studying the effects of microgravity, and a solar observatory.[44] NASA planned to have a Space Shuttle dock with it, and elevate Skylab to a higher safe altitude, but the Shuttle was not ready for flight before Skylab's re-entry on July 11, 1979.[45]

To save cost, NASA used one of the Saturn V rockets originally earmarked for a canceled Apollo mission to launch the Skylab. Apollo spacecraft were used for transporting astronauts to and from the station. Three three-man crews stayed aboard the station for periods of 28, 59, and 84 days. Skylab's habitable volume was 11,290 cubic feet (320 m3), which was 30.7 times bigger than that of the Apollo Command Module.[45]
Apollo-Soyuz Test Project (1972–75)
Apollo-Soyuz crews with models of spacecraft, 1975
Main article: Apollo-Soyuz Test Project

On May 24, 1972, US President Richard M. Nixon and Soviet Premier Alexei Kosygin signed an agreement calling for a joint manned space mission, and declaring intent for all future international manned spacecraft to be capable of docking with each other.[46] This authorized the Apollo-Soyuz Test Project (ASTP), involving the rendezvous and docking in Earth orbit of a surplus Apollo Command/Service Module with a Soyuz spacecraft. The mission took place in July 1975. This was the last US manned space flight until the first orbital flight of the Space Shuttle in April 1981.[47]

The mission included both joint and separate scientific experiments, and provided useful engineering experience for future joint US–Russian space flights, such as the Shuttle–Mir Program[48] and the International Space Station.
Space Shuttle program (1972–2011)
Main article: Space Shuttle program
Launch of the space shuttle

The Space Shuttle became the major focus of NASA in the late 1970s and the 1980s. Planned as a frequently launchable and mostly reusable vehicle, four space shuttle orbiters were built by 1985. The first to launch, Columbia, did so on April 12, 1981,[49] the 20th anniversary of the first known human space flight.[50]

Its major components were a spaceplane orbiter with an external fuel tank and two solid-fuel launch rockets at its side. The external tank, which was bigger than the spacecraft itself, was the only major component that was not reused. The shuttle could orbit in altitudes of 185–643 km (115–400 miles)[51] and carry a maximum payload (to low orbit) of 24,400 kg (54,000 lb).[52] Missions could last from 5 to 17 days and crews could be from 2 to 8 astronauts.[51]

On 20 missions (1983–98) the Space Shuttle carried Spacelab, designed in cooperation with the European Space Agency (ESA). Spacelab was not designed for independent orbital flight, but remained in the Shuttle's cargo bay as the astronauts entered and left it through an airlock.[53] Another famous series of missions were the launch and later successful repair of the Hubble Space Telescope in 1990 and 1993, respectively.[54]

In 1995, Russian-American interaction resumed with the Shuttle-Mir missions (1995–1998). Once more an American vehicle docked with a Russian craft, this time a full-fledged space station. This cooperation has continued with Russia and the United States as two of the biggest partners in the largest space station built: the International Space Station (ISS). The strength of their cooperation on this project was even more evident when NASA began relying on Russian launch vehicles to service the ISS during the two-year grounding of the shuttle fleet following the 2003 Space Shuttle Columbia disaster.

The Shuttle fleet lost two orbiters and 14 astronauts in two disasters: Challenger in 1986, and Columbia in 2003.[55] While the 1986 loss was mitigated by building the Space Shuttle Endeavour from replacement parts, NASA did not build another orbiter to replace the second loss.[55] NASA's Space Shuttle program had 135 missions when the program ended with the successful landing of the Space Shuttle Atlantis at the Kennedy Space Center on July 21, 2011. The program spanned 30 years with over 300 astronauts sent into space.[56]
International Space Station (1993–present)
Main article: International Space Station
The International Space Station

The International Space Station (ISS) combines NASA's Space Station Freedom project with the Soviet/Russian Mir-2 station, the European Columbus station, and the Japanese Kibō laboratory module.[57] NASA originally planned in the 1980s to develop Freedom alone, but US budget constraints led to the merger of these projects into a single multi-national program in 1993, managed by NASA, the Russian Federal Space Agency (RKA), the Japan Aerospace Exploration Agency (JAXA), the European Space Agency (ESA), and the Canadian Space Agency (CSA).[58][59] The station consists of pressurized modules, external trusses, solar arrays and other components, which have been launched by Russian Proton and Soyuz rockets, and the US Space Shuttles.[57] It is currently being assembled in Low Earth Orbit. The on-orbit assembly began in 1998, the completion of the US Orbital Segment occurred in 2011 and the completion of the Russian Orbital Segment is expected by 2016.[60][61][dated info] The ownership and use of the space station is established in intergovernmental treaties and agreements[62] which divide the station into two areas and allow Russia to retain full ownership of the Russian Orbital Segment (with the exception of Zarya),[63][64] with the US Orbital Segment allocated between the other international partners.[62]
The STS-131 (light blue) and Expedition 23 (dark blue) crew members in April 2010

Long duration missions to the ISS are referred to as ISS Expeditions. Expedition crew members typically spend approximately six months on the ISS.[65] The initial expedition crew size was three, temporarily decreased to two following the Columbia disaster. Since May 2009, expedition crew size has been six crew members.[66] Crew size is expected to be increased to seven, the number the ISS was designed for, once the Commercial Crew Program becomes operational.[67] The ISS has been continuously occupied for the past 15 years and 190 days, having exceeded the previous record held by Mir; and has been visited by astronauts and cosmonauts from 15 different nations.[68][69]

The station can be seen from the Earth with the naked eye and, as of 2016, is the largest artificial satellite in Earth orbit with a mass and volume greater than that of any previous space station.[70] The Soyuz spacecraft delivers crew members, stays docked for their half-year-long missions and then returns them home. Several uncrewed cargo spacecraft service the ISS, they are the Russian Progress spacecraft which has done so since 2000, the European Automated Transfer Vehicle (ATV) since 2008, the Japanese H-II Transfer Vehicle (HTV) since 2009, the American Dragon spacecraft since 2012, and the American Cygnus spacecraft since 2013. The Space Shuttle, before its retirement, was also used for cargo transfer and would often switch out expedition crew members, although it did not have the capability to remain docked for the duration of their stay. Until another US manned spacecraft is ready, crew members will travel to and from the International Space Station exclusively aboard the Soyuz.[71] The highest number of people occupying the ISS has been thirteen; this occurred three times during the late Shuttle ISS assembly missions.[72]

The ISS program is expected to continue until at least 2020, and may be extended beyond 2028.[73]
Commercial Resupply Services (2006–present)
Main article: Commercial Resupply Services
The Dragon is seen being berthed to the ISS in May 2012
The Standard variant of Cygnus is seen berthed to the ISS in September 2013

The development of the Commercial Resupply Services (CRS) vehicles began in 2006 with the purpose of creating American commercially operated uncrewed cargo vehicles to service the ISS.[74] The development of these vehicles was under a fixed price milestone-based program, meaning that each company that received a funded award had a list of milestones with a dollar value attached to them that they didn't receive until after they had successful completed the milestone.[75] Private companies were also required to have some "skin in the game" which refers raising an unspecified amount of private investment for their proposal.[76]

On December 23, 2008, NASA awarded Commercial Resupply Services contracts to SpaceX and Orbital Sciences Corporation.[77] SpaceX uses its Falcon 9 rocket and Dragon spacecraft.[78] Orbital Sciences uses its Antares rocket and Cygnus spacecraft. The first Dragon resupply mission occurred in May 2012.[79] The first Cygnus resupply mission occurred in September 2013.[80] The CRS program now provides for all America's ISS cargo needs; with the exception of a few vehicle-specific payloads that are delivered on the European ATV and the Japanese HTV.[81]
Commercial Crew Program (2010–present)
Main article: Commercial Crew Development

The Commercial Crew Development (CCDev) program was initiated in 2010 with the purpose of creating American commercially operated crewed spacecraft capable of delivering at least four crew members to the ISS, staying docked for 180 days and then returning them back to Earth.[82] It is hoped that these vehicles could also transport non-NASA customers to private space stations such those planned by Bigelow Aerospace.[83] Like COTS, CCDev is also a fixed price milestone-based developmental program that requires some private investment.[75]

In 2010, NASA announced the winners of the first phase of the program, a total of $50 million was divided among five American companies to foster research and development into human spaceflight concepts and technologies in the private sector. In 2011, the winners of the second phase of the program were announced, $270 million was divided among four companies.[84] In 2012, the winners of the third phase of the program were announced, NASA provided $1.1 billion divided among three companies to further develop their crew transportation systems.[85] In 2014, the winners of the final round were announced.[86] SpaceX's Dragon V2 (planned to be launched on a Falcon 9 v1.1) received a contract valued up to $2.6 billion and Boeing's CST-100 (to be launched on an Atlas V) received a contract valued up to $4.2 billion.[87] NASA expects these vehicles to begin transporting humans to the ISS in 2017.[87]

Dragon V2

Computer rendering of CST-100 in orbit

Beyond Low Earth Orbit program (2010–present)
Artist's rendering of the 70 mt variant of SLS launching Orion

For missions beyond low Earth orbit (BLEO), NASA has been directed to develop the Space Launch System (SLS), a Saturn-V class rocket, and the two to six person, beyond low Earth orbit spacecraft, Orion. In February 2010, President Barack Obama's administration proposed eliminating public funds for the Constellation program and shifting greater responsibility of servicing the ISS to private companies.[88] During a speech at the Kennedy Space Center on April 15, 2010, Obama proposed a new heavy-lift vehicle (HLV) to replace the formerly planned Ares V.[89] In his speech, Obama called for a manned mission to an asteroid as soon as 2025, and a manned mission to Mars orbit by the mid-2030s.[89] The NASA Authorization Act of 2010 was passed by Congress and signed into law on October 11, 2010.[90] The act officially canceled the Constellation program.[90]
Orion spacecraft design as of January 2013

The Authorization Act required a newly designed HLV be chosen within 90 days of its passing; the launch vehicle was given the name "Space Launch System". The new law also required the construction of a beyond low earth orbit spacecraft.[91] The Orion spacecraft, which was being developed as part of the Constellation program, was chosen to fulfill this role.[92] The Space Launch System is planned to launch both Orion and other necessary hardware for missions beyond low Earth orbit.[93] The SLS is to be upgraded over time with more powerful versions. The initial capability of SLS is required to be able to lift 70 mt into LEO. It is then planned to be upgraded to 105 mt and then eventually to 130 mt.[92][94]

Exploration Flight Test 1 (EFT-1), an unmanned test flight of Orion's crew module, was launched on December 5, 2014, atop a Delta IV Heavy rocket.[94] Exploration Mission-1 (EM-1) is the unmanned initial launch of SLS that would also send Orion on a circumlunar trajectory, which is planned for 2017.[94] The first manned flight of Orion and SLS, Exploration Mission 2 (EM-2) is to launch between 2019 and 2021; it is a 10- to 14-day mission planned to place a crew of four into Lunar orbit.[94] As of March 2012, the destination for EM-3 and the intermediate focus for this new program is still in-flux.[95]
Unmanned programs
Pioneer 3 and 4 launched in 1958 and 1959, respectively
Main article: Unmanned NASA missions

More than 1,000 unmanned missions have been designed to explore the Earth and the solar system.[96] Besides exploration, communication satellites have also been launched by NASA.[97] The missions have been launched directly from Earth or from orbiting space shuttles, which could either deploy the satellite itself, or with a rocket stage to take it farther.

The first US unmanned satellite was Explorer 1, which started as an ABMA/JPL project during the early part of the Space Race. It was launched in January 1958, two months after Sputnik. At the creation of NASA the Explorer project was transferred to this agency and still continues to this day. Its missions have been focusing on the Earth and the Sun, measuring magnetic fields and the solar wind, among other aspects.[98] A more recent Earth mission, not related to the Explorer program, was the Hubble Space Telescope, which as mentioned above was brought into orbit in 1990.[99]

The inner Solar System has been made the goal of at least four unmanned programs. The first was Mariner in the 1960s and '70s, which made multiple visits to Venus and Mars and one to Mercury. Probes launched under the Mariner program were also the first to make a planetary flyby (Mariner 2), to take the first pictures from another planet (Mariner 4), the first planetary orbiter (Mariner 9), and the first to make a gravity assist maneuver (Mariner 10). This is a technique where the satellite takes advantage of the gravity and velocity of planets to reach its destination.[100]

The first successful landing on Mars was made by Viking 1 in 1976. Twenty years later a rover was landed on Mars by Mars Pathfinder.[101]

Outside Mars, Jupiter was first visited by Pioneer 10 in 1973. More than 20 years later Galileo sent a probe into the planet's atmosphere, and became the first spacecraft to orbit the planet.[102] Pioneer 11 became the first spacecraft to visit Saturn in 1979, with Voyager 2 making the first (and so far only) visits to Uranus and Neptune in 1986 and 1989, respectively. The first spacecraft to leave the solar system was Pioneer 10 in 1983. For a time it was the most distant spacecraft, but it has since been surpassed by both Voyager 1 and Voyager 2.[103]

Pioneers 10 and 11 and both Voyager probes carry messages from the Earth to extraterrestrial life.[104][105] Communication can be difficult with deep space travel. For instance, it took about 3 hours for a radio signal to reach the New Horizons spacecraft when it was more than halfway to Pluto.[106] Contact with Pioneer 10 was lost in 2003. Both Voyager probes continue to operate as they explore the outer boundary between the Solar System and interstellar space.[107]

On November 26, 2011, NASA's Mars Science Laboratory mission was successfully launched for Mars. Curiosity successfully landed on Mars on August 6, 2012, and subsequently began its search for evidence of past or present life on Mars.[108][109][110]
Recent and planned activities

NASA's ongoing investigations include in-depth surveys of Mars and Saturn and studies of the Earth and the Sun. Other active spacecraft missions are MESSENGER for Mercury, New Horizons (for Jupiter, Pluto, and beyond), and Dawn for the asteroid belt. NASA continued to support in situ exploration beyond the asteroid belt, including Pioneer and Voyager traverses into the unexplored trans-Pluto region, and Gas Giant orbiters Galileo (1989–2003), Cassini (1997–), and Juno (2011–).

The New Horizons mission to Pluto was launched in 2006 and successfully performed a flyby of Pluto on July 14, 2015. The probe received a gravity assist from Jupiter in February 2007, examining some of Jupiter's inner moons and testing on-board instruments during the flyby. On the horizon of NASA's plans is the MAVEN spacecraft as part of the Mars Scout Program to study the atmosphere of Mars.[111]
Vision mission for an interstellar precursor spacecraft by NASA

On December 4, 2006, NASA announced it was planning a permanent moon base.[112] The goal was to start building the moon base by 2020, and by 2024, have a fully functional base that would allow for crew rotations and in-situ resource utilization. However, in 2009, the Augustine Committee found the program to be on a "unsustainable trajectory."[113] In 2010, President Barack Obama halted existing plans, including the Moon base, and directed a generic focus on manned missions to asteroids and Mars, as well as extending support for the International Space Station.[114]

Since 2011, NASA's strategic goals have been[115]

Extend and sustain human activities across the solar system
Expand scientific understanding of the Earth and the universe
Create innovative new space technologies
Advance aeronautics research
Enable program and institutional capabilities to conduct NASA's aeronautics and space activities
Share NASA with the public, educators, and students to provide opportunities to participate

In August 2011, NASA accepted the donation of two space telescopes from the National Reconnaissance Office. Despite being stored unused, the instruments are superior to the Hubble Space Telescope.[116]

In September 2011, NASA announced the start of the Space Launch System program to develop a human-rated heavy lift vehicle. The Space Launch System is intended to launch the Orion Multi-Purpose Crew Vehicle and other elements towards the Moon, near-Earth asteroids, and one day Mars.[117] The Orion MPCV conducted an unmanned test launch on a Delta IV Heavy rocket in December 2014.[118]
Curiosity's wheel on Mars, 2012

On August 6, 2012, NASA landed the rover Curiosity on Mars. On August 27, 2012, Curiosity transmitted the first pre-recorded message from the surface of Mars back to Earth, made by Administrator Charlie Bolden:
“ Hello. This is Charlie Bolden, NASA Administrator, speaking to you via the broadcast capabilities of the Curiosity Rover, which is now on the surface of Mars.

Since the beginning of time, humankind’s curiosity has led us to constantly seek new life...new possibilities just beyond the horizon. I want to congratulate the men and women of our NASA family as well as our commercial and government partners around the world, for taking us a step beyond to Mars.
This is an extraordinary achievement. Landing a rover on Mars is not easy – others have tried – only America has fully succeeded. The investment we are making...the knowledge we hope to gain from our observation and analysis of Gale Crater, will tell us much about the possibility of life on Mars as well as the past and future possibilities for our own planet. Curiosity will bring benefits to Earth and inspire a new generation of scientists and explorers, as it prepares the way for a human mission in the not too distant future. Thank you.[119]
”
Scientific research
For technologies funded or otherwise supported by NASA, see NASA spin-off technologies.
Main article: NASA research
Staff and leadership
Main article: List of NASA Administrators

NASA's administrator is the agency's highest-ranking official and serves as the senior space science adviser to the President of the United States. The agency's administration is located at NASA Headquarters in Washington, DC and provides overall guidance and direction.[120] Except under exceptional circumstances, NASA civil service employees are required to be citizens of the United States.[121]

The first administrator was Dr. T. Keith Glennan, appointed by President Dwight D. Eisenhower. During his term he brought together the disparate projects in American space development research.[122]

The third administrator was James E. Webb (served 1961–1968), appointed by President John F. Kennedy. In order to implement the Apollo program to achieve Kennedy's Moon landing goal by the end of the 1960s, Webb directed major management restructuring and facility expansion, establishing the Houston Manned Spacecraft (Johnson) Center and the Florida Launch Operations (Kennedy) Center.

In 2009, President Barack Obama nominated Charles Bolden as NASA's twelfth administrator.[123] Administrator Bolden is one of three NASA administrators who were astronauts, along with Richard H. Truly (served 1989–1992) and Frederick D. Gregory (acting, 2005).
Facilities
Jet Propulsion Laboratory complex in Pasadena, California
Jet Propulsion Laboratory complex in Pasadena, California
Vehicle Assembly Building and Launch Control Center at Kennedy Space Center
Vehicle Assembly and Launch Control at Kennedy Space Center
Main article: NASA facilities

NASA's facilities are research, construction and communication centers to help its missions. Some facilities serve more than one application for historic or administrative reasons. NASA also operates a short-line railroad at the Kennedy Space Center and own special aircraft, for instance two Boeing 747 that transport Space Shuttle orbiter.

John F. Kennedy Space Center (KSC), is one of the best-known NASA facilities. It has been the launch site for every United States human space flight since 1968. Although such flights are currently on pause, KSC continues to manage and operate unmanned rocket launch facilities for America's civilian space program from three pads at the adjoining Cape Canaveral Air Force Station.

Lyndon B. Johnson Space Center (JSC) in Houston is home to the Christopher C. Kraft Jr. Mission Control Center, where all flight control is managed for manned space missions. JSC is the lead NASA center for activities regarding the International Space Station and also houses the NASA Astronaut Corps that selects, trains, and provides astronauts as crew members for US and international space missions.

Another major facility is Marshall Space Flight Center in Huntsville, Alabama at which the Saturn 5 rocket and Skylab were developed.[124] The JPL worked together with ABMA, one of the agencies behind Explorer 1, the first American space mission.
FCR 1 in 2009 during the STS-128 mission, JSC in Houston

John F. Kennedy Space Center, Florida
Ames Research Center, Moffett Field, California
Hugh L. Dryden Flight Research Facility, Edwards, California
Goddard Space Flight Center, Greenbelt, Maryland
Jet Propulsion Laboratory, near Pasadena, California
Lyndon B. Johnson Space Center, Houston, Texas
Langley Research Center, Hampton, Virginia
John H. Glenn Research Center, Cleveland, Ohio
Plum Brook Station Test Facilities, Sandusky, Ohio
George C. Marshall Space Flight Center, Huntsville, Alabama
Michoud Assembly Facility, New Orleans, Louisiana
John C. Stennis Space Center, Bay St. Louis, Mississippi
Wallops Flight Facility, Wallops Island, Virginia

Budget
NASA's budget from 1958 to 2012 as a percentage of federal budget
An artist's conception, from NASA, of an astronaut planting a US flag on Mars. A manned mission to Mars has been discussed as a possible NASA mission since the 1960s.
Main article: Budget of NASA

NASA's budget has generally been approximately 1% of the federal budget from the early 1970s on, after briefly peaking at approximately 4.41% in 1966 during the Apollo program.[125] Public perception of NASA's budget has differed significantly from reality; a 1997 poll indicated that most Americans responded that 20% of the federal budget went to NASA.[126]

The percentage of federal budget that NASA has been allocated has been steadily dropping since the Apollo program and in 2012 it was estimated at 0.48% of the federal budget.[127] In a March 2012 meeting of the United States Senate Science Committee, Neil deGrasse Tyson testified that "Right now, NASA’s annual budget is half a penny on your tax dollar. For twice that—a penny on a dollar—we can transform the country from a sullen, dispirited nation, weary of economic struggle, to one where it has reclaimed its 20th century birthright to dream of tomorrow."[128][129]

For Fiscal Year 2015, NASA received an appropriation of US$18.01 billion from Congress—$549 million more than requested and approximately $350 million more than the 2014 NASA budget passed by Congress.[130]
Environmental impact

The exhaust gases produced by rocket propulsion systems, both in Earth's atmosphere and in space, can adversely effect the Earth's environment. Some hypergolic rocket propellants, such as hydrazine, are highly toxic prior to combustion, but decompose into less toxic compounds after burning. Rockets using hydrocarbon fuels, such as kerosene, release carbon dioxide and soot in their exhaust.[131] However, carbon dioxide emissions are insignificant compared to those from other sources; on average, the United States consumed 802,620,000 US gallons (3.0382×109 L) gallons of liquid fuels per day in 2014, while a single Falcon 9 rocket first stage burns around 25,000 US gallons (95,000 L) of kerosene fuel per launch.[132][133] Even if a Falcon 9 were launched every single day, it would only represent 0.006% of liquid fuel consumption (and carbon dioxide emissions) for that day. Additionally, the exhaust from LOx- and LH2- fueled engines, like the SSME, is almost entirely water vapor.[134] NASA addressed environmental concerns with its canceled Constellation program in accordance with the National Environmental Policy Act in 2011.[135] In contrast, ion engines use harmless noble gases like xenon for propulsion.[136][137]

On May 8, 2003, Environmental Protection Agency recognized NASA as the first federal agency to directly use landfill gas to produce energy at one of its facilities—the Goddard Space Flight Center, Greenbelt, Maryland.[138]

An example of NASA's environmental efforts is the NASA Sustainability Base. Additionally, the Exploration Sciences Building was awarded the LEED Gold rating in 2010.[139]
Observations

Plot of orbits of known Potentially Hazardous Asteroids (size over 460 feet (140 m) and passing within 4.7 million miles (7.6×106 km) of Earth's orbit)

Various nebulae observed from a NASA space telescope

1 Ceres

Pluto and Charon

Spacecraft

Cassini-Huygens

Hubble Space Telescope

Curiosity rover

Examples of NASA missions by target
Examples of robotic missions Spacecraft Launch
year Mercury Venus Mars Jupiter Saturn Uranus Neptune Pluto
Mariner 2 1962 Flyby
Mariner 4 1964 Flyby
Mariner 5 1967 Flyby
Mariner 9 1971 Orbiter
Pioneer 10 1972 Flyby
Pioneer 11 1973 Flyby Flyby
Mariner 10 1973 Flyby Flyby
Viking 1 & Viking 2 1975 Orbiters
Landers
Voyager 1 1977 Flyby Flyby
Voyager 2 1977 Flyby Flyby Flyby Flyby
Galileo 1989 Flyby Orbiter
Magellan 1989 Orbiter
Mars Global Surveyor 1996 Orbiter
Cassini 1997 Flyby Flyby Orbiter
Mars Odyssey 2001 Orbiter
Spirit & Opportunity 2003 Rovers
MESSENGER 2004 Orbiter Flyby
MRO 2005 Orbiter
New Horizons 2006 Flyby Flyby
Juno 2011 Orbiter
Curiosity (MSL) 2011 Rover
MAVEN 2013 Orbiter
Spacecraft Launch
year Mercury Venus Mars Jupiter Saturn Uranus Neptune Pluto
Plutonium
Radioisotope within a graphite shell that goes into the generator.

NASA has made use of technologies such as the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG), which is a type of Radioisotope Thermoelectric Generator used on space missions[140]
See also
Portal icon Government of the United States portal
Portal icon Spaceflight portal

Astronomy Picture of the Day
Department of Defense Manned Space Flight Support Office
List of government space agencies
List of NASA aircraft
List of NASA missions
List of United States rockets
NASA Advanced Space Transportation Program
NASA awards and decorations
NASA insignia
NASA Research Park
NASA TV
NASAcast
Small Explorer program
Space policy of the Barack Obama administration
TechPort (NASA)

References

Lale Tayla & Figen Bingul (2007). "NASA stands "for the benefit of all."—Interview with NASA's Dr. Süleyman Gokoglu". The Light Millennium.
US Centennial of Flight Commission, NACA. centennialofflight.net. Retrieved on November 3, 2011.
"NASA workforce profile". NASA. January 11, 2011. Retrieved December 17, 2012.
Dreier, Casey (18 December 2015). "[Updated] An Extraordinary Budget for NASA in 2016 - Congressional omnibus increases the space agency's budget by $1.3 billion". The Planetary Society. Retrieved 4 February 2016.
"Ike in History: Eisenhower Creates NASA". Eisenhower Memorial. 2013. Retrieved November 27, 2013.
"The National Aeronautics and Space Act". NASA. 2005. Retrieved August 29, 2007.
Bilstein, Roger E. (1996). "From NACA to NASA". NASA SP-4206, Stages to Saturn: A Technological History of the Apollo/Saturn Launch Vehicles. NASA. pp. 32–33. ISBN 978-0-16-004259-1. Retrieved May 6, 2013.
Netting, Ruth (June 30, 2009). "Earth—NASA Science". Retrieved July 15, 2009.
Netting, Ruth (January 8, 2009). "Heliophysics—NASA Science". Retrieved July 15, 2009.
Roston, Michael (August 28, 2015). "NASA’s Next Horizon in Space". New York Times. Retrieved August 28, 2015.
Netting, Ruth (July 13, 2009). "Astrophysics—NASA Science". Retrieved July 15, 2009.
"The NACA, NASA, and the Supersonic-Hypersonic Frontier" (PDF). NASA. Retrieved September 30, 2011.
Subcommittee On Military Construction, United States. Congress. Senate. Committee on Armed Services (January 21–24, 1958). Supplemental military construction authorization (Air Force).: Hearings, Eighty-fifth Congress, second session, on H.R. 9739.
"T. KEITH GLENNAN". NASA. August 4, 2006. Retrieved July 15, 2009.
Executive Order 10849 (Wikisource)
von Braun, Werner (1963). "Recollections of Childhood: Early Experiences in Rocketry as Told by Werner Von Braun 1963". MSFC History Office. NASA Marshall Space Flight Center. Retrieved July 15, 2009.
Van Atta, Richard (April 10, 2008). "50 years of Bridging the Gap" (PDF). Archived from the original (PDF) on February 24, 2009. Retrieved July 15, 2009.
The Air Force definition of outer space differs from that of the International Aeronautical Federation, which is 100 kilometers (330,000 ft).
Aerospaceweb, North American X-15. Aerospaceweb.org. Retrieved on November 3, 2011.
Aircraft Museum X-15." Aerospaceweb.org, November 24, 2008.
NASA, X-15 Hypersonic Research Program, retrieved October 17, 2011
Encyclopedia Astronautica, Project 7969, retrieved October 17, 2011
NASA, Project Mercury Overview, retrieved October 17, 2011
Swenson Jr., Loyd S.; Grimwood, James M.; Alexander, Charles C. (1989). "11-4 Shepard's Ride". In Woods, David; Gamble, Chris. This New Ocean: A History of Project Mercury (url). Published as NASA Special Publication-4201 in the NASA History Series (NASA). Retrieved July 14, 2009.
Swenson Jr., Loyd S.; Grimwood, James M.; Alexander, Charles C. (1989). "13-4 An American in Orbit". In Woods, David; Gamble, Chris. This New Ocean: A History of Project Mercury (url). Published as NASA Special Publication-4201 in the NASA History Series (NASA). Retrieved July 14, 2009.
"Mercury Manned Flights Summary". NASA. Retrieved October 9, 2011.
"NASA history, Gagarin". NASA. Retrieved October 9, 2011.
Barton C. Hacker; James M. Grimwood (December 31, 2002). "10-1 The Last Hurdle". On the Shoulders of Titans: A History of Project Gemini (url). NASA. ISBN 978-0-16-067157-9. Archived from the original on February 1, 2010. Retrieved July 14, 2009.
Barton C. Hacker; James M. Grimwood (December 31, 2002). "12-5 Two Weeks in a Spacecraft". On the Shoulders of Titans: A History of Project Gemini. NASA. ISBN 978-0-16-067157-9. Archived from the original on February 1, 2010. Retrieved July 14, 2009.
Barton C. Hacker; James M. Grimwood (December 31, 2002). "13-3 An Alternative Target". On the Shoulders of Titans: A History of Project Gemini. NASA. ISBN 978-0-16-067157-9. Archived from the original on February 1, 2010. Retrieved July 14, 2009.
John F. Kennedy "Landing a man on the Moon" Address to Congress on YouTube, speech
Butts, Glenn; Linton, Kent (April 28, 2009). "The Joint Confidence Level Paradox: A History of Denial, 2009 NASA Cost Symposium" (PDF). pp. 25–26.
"Consumer Price Index (estimate) 1800–". Federal Reserve Bank of Minneapolis. Retrieved November 10, 2015.
Nichols, Kenneth David (1987). The Road to Trinity: A Personal Account of How America's Nuclear Policies Were Made, pp 34–35. New York: William Morrow and Company. ISBN 0-688-06910-X. OCLC 15223648.
"Saturn V". Encyclopedia Astronautica. Retrieved October 13, 2011.
"Apollo 8: The First Lunar Voyage". NASA. Retrieved October 13, 2011.
Siddiqi, Asif A. (2003). The Soviet Space Race with Apollo. Gainesville: University Press of Florida. pp. 654–656. ISBN 0-8130-2628-8.
"Apollo 9: Earth Orbital trials". NASA. Retrieved October 13, 2011.
"Apollo 10: The Dress Rehearsal". NASA. Retrieved October 13, 2011.
"The First Landing". NASA. Retrieved October 13, 2011.
Chaikin, Andrew (March 16, 1998). A Man on the Moon. New York: Penguin Books. ISBN 978-0-14-027201-7.
The Phrase Finder:...a giant leap for mankind, retrieved October 1, 2011
30th Anniversary of Apollo 11, Manned Apollo Missions. NASA, 1999.
Belew, Leland F., ed. (1977). Skylab Our First Space Station—NASA report (PDF). NASA. NASA-SP-400. Retrieved July 15, 2009.
Benson, Charles Dunlap and William David Compton. Living and Working in Space: A History of Skylab. NASA publication SP-4208.
Gatland, Kenneth (1976). Manned Spacecraft, Second Revision. New York: Macmillan Publishing Co., Inc. p. 247. ISBN 0-02-542820-9.
Grinter, Kay (April 23, 2003). "The Apollo Soyuz Test Project". Retrieved July 15, 2009.
NASA, Shuttle-MIR history, retrieved October 15, 2011
Bernier, Serge (May 27, 2002). Space Odyssey: The First Forty Years of Space Exploration. Cambridge University Press. ISBN 978-0-521-81356-3.
Encyclopedia Astronautica, Vostok 1, retrieved October 18, 2011
NASA, Shuttle Basics, retrieved October 18, 2011
Encyclopedia Astronautica, Shuttle, retrieved October 18, 2011
Encyclopedia Astronautica, Spacelab. Retrieved October 20, 2011
Encyclopedia Astronautica, HST. Retrieved October 20, 2011
Watson, Traci (January 8, 2008). "Shuttle delays endanger space station". USA Today. Retrieved July 15, 2009.
"NASA's Last Space Shuttle Flight Lifts Off From Cape Canaveral". KHITS Chicago. July 8, 2011.
John E. Catchpole (June 17, 2008). The International Space Station: Building for the Future. Springer-Praxis. ISBN 978-0-387-78144-0.
"Human Spaceflight and Exploration—European Participating States". European Space Agency (ESA). 2009. Retrieved January 17, 2009.
Gary Kitmacher (2006). Reference Guide to the International Space Station. Canada: Apogee Books. pp. 71–80. ISBN 978-1-894959-34-6. ISSN 1496-6921.
Gerstenmaier, William (October 12, 2011). "Statement of William H. Gerstenmaier Associate Administrator for HEO NASA before the Subcommittee on Space and Aeronautics Committee on Science, Space and Technology U. S. House of Representatives" (PDF). United States House of Representatives. Retrieved August 31, 2012.
Afanasev, Igor; Vorontsov, Dmitrii (January 11, 2012). "The Russian ISS segment is to be completed by 2016". Air Transport Observer. Retrieved October 14, 2012.
"ISS Intergovernmental Agreement". European Space Agency (ESA). April 19, 2009. Retrieved April 19, 2009.
"Memorandum of Understanding Between the National Aeronautics and Space Administration of the United States of America and the Russian Space Agency Concerning Cooperation on the Civil International Space Station". NASA. January 29, 1998. Retrieved April 19, 2009.
Zak, Anatoly (October 15, 2008). "Russian Segment: Enterprise". RussianSpaceWeb. Retrieved August 4, 2012.
"ISS Fact sheet: FS-2011-06-009-JSC" (PDF). NASA. 2011. Retrieved September 2, 2012.
"MCB Joint Statement Representing Common Views on the Future of the ISS" (PDF). International Space Station Multilateral Coordination Board. February 3, 2010. Retrieved August 16, 2012.
Leone, Dan (June 20, 2012). "Wed, 20 June, 2012 NASA Banking on Commercial Crew To Grow ISS Population". Space News. Retrieved September 1, 2012.
"Nations Around the World Mark 10th Anniversary of International Space Station". NASA. November 17, 2008. Retrieved March 6, 2009.
Boyle, Rebecca (November 11, 2010). "The International Space Station Has Been Continuously Inhabited for Ten Years Today". Popular Science. Retrieved September 1, 2012.
International Space Station, Retrieved October 20, 2011
Chow, Denise (November 17, 2011). "U.S. Human Spaceflight Program Still Strong, NASA Chief Says". Space.com. Retrieved July 2, 2012.
Potter, Ned (July 17, 2009). "Space Shuttle, Station Dock: 13 Astronauts Together". ABC News. Retrieved September 7, 2012.
Leone, Dan (March 29, 2012). "Sen. Mikulski Questions NASA Commercial Crew Priority". Space News. Retrieved June 30, 2012.
"NASA Selects Crew and Cargo Transportation to Orbit Partners" (Press release). NASA. August 18, 2006. Retrieved November 21, 2006.
"Moving Forward: Commercial Crew Development Building the Next Era in Spaceflight" (PDF). Rendezvous. NASA. 2010. pp. 10–17. Retrieved February 14, 2011. "Just as in the COTS projects, in the CCDev project we have fixed-price, pay-for-performance milestones" Thorn said. "There’s no extra money invested by NASA if the projects cost more than projected."
McAlister, Phil (October 2010). "The Case for Commercial Crew" (PDF). NASA. Retrieved July 2, 2012.
"NASA Awards Space Station Commercial Resupply Services Contracts". NASA, December 23, 2008.
"Space Exploration Technologies Corporation – Press". Spacex.com. Retrieved July 17, 2009.
Clark, Stephen (June 2, 2012). "NASA expects quick start to SpaceX cargo contract". SpaceFlightNow. Retrieved June 30, 2012.
Bergin, Chris (September 28, 2013). "Orbital’s Cygnus successfully berthed on the ISS". NASASpaceFlight.com (not affiliated with NASA). Retrieved October 17, 2013.
"SpaceX/NASA Discuss launch of Falcon 9 rocket and Dragon capsule". NASA. May 22, 2012. Retrieved June 23, 2012.
Berger, Brian (February 1, 2011). "Biggest CCDev Award Goes to Sierra Nevada". Imaginova Corp. Retrieved December 13, 2011.
Morring, Frank (October 10, 2012). "Boeing Gets Most Money With Smallest Investment". Aviation Week. Retrieved October 5, 2012.
Dean, James. "NASA awards $270 million for commercial crew efforts" at the Wayback Machine (archived May 11, 2011). space.com, April 18, 2011.
"NASA Announces Next Steps in Effort to Launch Americans from U.S. Soil". NASA. August 3, 2012. Retrieved August 3, 2012.
Bolden, Charlie. "American Companies Selected to Return Astronaut Launches to American Soil". NASA.gov. Retrieved September 16, 2014.
Foust, Jeff (September 19, 2014). "NASA Commercial Crew Awards Leave Unanswered Questions". Space News. Retrieved September 21, 2014. "“We basically awarded based on the proposals that we were given,” Kathy Lueders, NASA commercial crew program manager, said in a teleconference with reporters after the announcement. “Both contracts have the same requirements. The companies proposed the value within which they were able to do the work, and the government accepted that.”"
Achenbach, Joel (February 1, 2010). "NASA budget for 2011 eliminates funds for manned lunar missions". Washington Post. Retrieved February 1, 2010.
"President Barack Obama on Space Exploration in the 21st Century". Office of the Press Secretary. April 15, 2010. Retrieved July 4, 2012.
"Today – President Signs NASA 2010 Authorization Act". Universetoday.com. Retrieved November 20, 2010.
Svitak, Amy (March 31, 2011). "Holdren: NASA Law Doesn't Square with Budgetary Reality". Space News. Retrieved July 4, 2012.
"Bill Text - 111th Congress (2009-2010) - THOMAS (Library of Congress)". loc.gov.
"NASA Announces Design for New Deep Space Exploration System". NASA. September 14, 2011. Retrieved April 28, 2012.
Bergin, Chris (February 23, 2012). "Acronyms to Ascent – SLS managers create development milestone roadmap". NASA. Retrieved April 29, 2012.
Bergin, Chris (March 26, 2012). "NASA Advisory Council: Select a Human Exploration Destination ASAP". NasaSpaceflight (not affiliated with NASA). Retrieved April 28, 2012.
"Launch History (Cumulative)" (PDF). NASA. Retrieved September 30, 2011.
"NASA Experimental Communications Satellites, 1958–1995". NASA. Retrieved September 30, 2011.
"NASA, Explorers program". NASA. Retrieved September 20, 2011.
NASA mission STS-31 (35) Archived 18 August 2011 at WebCite
"JPL, Chapter 4. Interplanetary Trajectories". NASA. Retrieved September 30, 2011.
"Missions to Mars". The Planet Society. Retrieved September 30, 2011.
"Missions to Jupiter". The Planet Society. Retrieved September 30, 2011.
"JPL Voyager". JPL. Retrieved September 30, 2011.
"Pioneer 10 spacecraft send last signal". NASA. Retrieved September 30, 2011.
"The golden record". JPL. Retrieved September 30, 2011.
"New Horizon". JHU/APL. Retrieved September 30, 2011.
"Voyages Beyond the Solar System: The Voyager Interstellar Mission". NASA. Retrieved September 30, 2011.
NASA Staff (November 26, 2011). "Mars Science Laboratory". NASA. Retrieved November 26, 2011.
"NASA Launches Super-Size Rover to Mars: 'Go, Go!'". New York Times. Associated Press. November 26, 2011. Retrieved November 26, 2011.
Kenneth Chang (August 6, 2012). "Curiosity Rover Lands Safely on Mars". The New York Times. Retrieved August 6, 2012.
Wilson, Jim (September 15, 2008). "NASA Selects 'MAVEN' Mission to Study Mars Atmosphere". NASA. Retrieved July 15, 2009.
NASA Office of Public Affairs (December 4, 2006). "GLOBAL EXPLORATION STRATEGY AND LUNAR ARCHITECTURE" (PDF). NASA. Retrieved July 15, 2009.
"Review of United States Human Space Flight Plans Committee" (PDF). Office of Science and Technology Policy. October 22, 2009. Retrieved December 13, 2011.
Goddard, Jacqui (February 2, 2010). "Nasa reduced to pipe dreams as Obama cancels Moon flights". The Times (London). Retrieved May 19, 2010.
"NASA Strategic Plan, 2011" (PDF). NASA Headquarters.
Boyle, Rebecca (June 5, 2012). "NASA Adopts Two Spare Spy Telescopes, Each Maybe More Powerful than Hubble". Popular Science. Popular Science Technology Group. Retrieved June 5, 2012.
"NASA Announces Design for New Deep Space Exploration System". NASA. September 14, 2011. Retrieved December 13, 2011.
"NASA’s Orion Flight Test Yields Critical Data". NASA.
JPL, NASA. "First Recorded Voice from Mars". nasa.gov.
Shouse, Mary (July 9, 2009). "Welcome to NASA Headquarters". Retrieved July 15, 2009.
Information for Non U.S. Citizens, NASA (downloaded September 16, 2013)
"T. Keith Glennan biography". NASA. August 4, 2006. Retrieved July 5, 2008.
Cabbage, Michael (July 15, 2009). "Bolden and Garver Confirmed by U.S. Senate" (Press release). NASA. Retrieved July 16, 2009.
"MSFC_Fact_sheet" (PDF). NASA. Retrieved October 1, 2011.
Rogers, Simon. (February 1, 2010) Nasa budgets: US spending on space travel since 1958 |Society. theguardian.com. Retrieved on August 26, 2013.
Launius, Roger D. "Public opinion polls and perceptions of US human spaceflight". Division of Space History, National Air and Space Museum, Smithsonian Institution.
"Fiscal Year 2013 Budget Estimates" (PDF). NASA. Retrieved February 13, 2013.
"Past, Present, and Future of NASA — U.S. Senate Testimony". Hayden Planetarium. March 7, 2012. Retrieved December 4, 2012.
"Past, Present, and Future of NASA — U.S. Senate Testimony (Video)". Hayden Planetarium. March 7, 2012. Retrieved December 4, 2012.
Clark, Stephen (December 14, 2014). "NASA gets budget hike in spending bill passed by Congress". Spaceflight Now. Retrieved December 15, 2014.
"Rocket Soot Emissions and Climate Change". The Aerospace Corporation. July 31, 2013. Retrieved January 7, 2014.
"Short-Term Energy Outlook" (PDF). U.S. Energy Information Administration. 2016-02-09. "U.S. Petroleum and Other Liquids"
"Spaceflight Now - Dragon Mission Report - Mission Status Center". Retrieved July 4, 2015.
"Space Shuttle Main Engines". NASA. July 16, 2009. Retrieved January 20, 2015.
"Constellation Programmatic Environmental Impact Statement". NASA. August 1, 2011. Retrieved June 19, 2014.
Shiga, David (2007-09-28). "Next-generation ion engine sets new thrust record". NewScientist. Retrieved 2011-02-02.
Goto, T; Nakata Y; Morita S (2003). "Will xenon be a stranger or a friend?: the cost, benefit, and future of xenon anesthesia". Anesthesiology 98 (1): 1–2. doi:10.1097/00000542-200301000-00002. PMID 12502969. Retrieved 2010-09-15.
Michael K. Ewert (2006). "Johnson Space Center's Role in a Sustainable Future" (PDF). NASA. Retrieved April 28, 2008.
"NASA - NASA's New Building Awarded the U.S. Green Building Council LEED Gold Rating". nasa.gov.

"Radioisotope Power Systems for Space Exploration" (PDF). March 2011. Retrieved March 13, 2015.

External links
Listen to this article (info/dl)
Menu
0:00

This audio file was created from a revision of the "NASA" article dated September 1, 2005, and does not reflect subsequent edits to the article. (Audio help)
More spoken articles
Wikimedia Commons has media related to NASA.
Wikisource has original text related to this article:
National Aeronautics and Space Act
Wikisource has original works written by or about:
NASA

General

Official NASA site
NASA Engineering and Safety Center
NASA Photos and NASA Images
NASA Launch Schedule
NASA Television and NASA podcasts
NASA on Google+
NASA's channel on YouTube
@NASA on Twitter
NASA on Facebook
NASA in the Federal Register
NASA Watch, an agency watchdog site
The Gateway to Astronaut Photography of Earth
NASA Documents relating to the Space Program, 1953–62, Dwight D. Eisenhower Presidential Library
Online documents pertaining to the early history and development of NASA, Dwight D. Eisenhower Presidential Library
NASA records available for research at the National Archives at Atlanta
Technical Report Archive and Image Library (TRAIL) – historic technical reports from NASA and other federal agencies
NASA Alumni League, NAL Florida Chapter, NAL JSC Chapter
Works by NASA at Project Gutenberg
Works by or about NASA at Internet Archive