NASA Manned Programs

The X-15 was an NACA experimental rocket-powered hypersonic research aircraft, developed in conjunction with the U.S. 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). One hundred ninety-nine 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, pressurized space suits, and horizon definition for navigation.[21] The reentry and landing data collected were valuable to NASA for designing the Space Shuttle.[19]

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. U.S. Air Force's Man in Space Soonest program looked at 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 beat the U.S. for 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.

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 then canceled, and Gemini caught up while spacecraft designer Sergei Korolev developed the Soyuz spacecraft, their answer to Apollo.

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 $205 billion in present-day US dollars.[33] (In comparison, the Manhattan Project cost roughly $26.2 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.

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[42] when he stepped down on the Moon.

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 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]

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.

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 space flight by Yuri Gagarin.[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 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]

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] 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]

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 14 years and 8 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 2014, 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 but may be extended until 2028 or possibly beyond that.[73]

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]

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][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] This phase of the CCDev program is expected to last from June 3, 2012 to May 31, 2014.[85] The winners of this latest round were SpaceX's Dragon planned to be launched on a Falcon 9, Boeing's CST-100 planned to be launched on an Atlas V and Sierra Nevada's Dream Chaser, which is also planned to be launched on an Atlas V.[86] NASA will most likely only choose one provider for the Commercial Crew program, this vehicle is expected by NASA to become operational around 2017.[87][88]

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.[89] 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.[90] 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.[90] The NASA Authorization Act of 2010 was passed by Congress and signed into law on October 11, 2010.[91] The act officially canceled the Constellation program.[91]

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.[92] The Orion spacecraft, which was being developed as part of the Constellation program, was chosen to fulfill this role.[93] The Space Launch System is planned to launch both Orion and other necessary hardware for missions beyond low Earth orbit.[94] 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.[93][95]

Exploration Flight Test 1 (EFT-1), an unmanned test flight of Orion's crew module, is planned to be launched in 2014 on a Delta IV Heavy rocket.[95] 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.[95] 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.[95] As of March 2012, the destination for EM-3 and the intermediate focus for this new program is still in-flux.[96]