Space Shuttle

The Space Shuttle is a true aerospace vehicle: it is launched in a rocket, orbits the Earth like a spacecraft and lands like a conventional airplane. The American Space Shuttle is the major component of the United States Space Transportation System (STS). Designs for the shuttle were conceived in the early 1970s as part of the United States' plan for the development of space transportation. The plan called for a balance between manned and unmanned operations. The shuttle supports the mannered operations of that plan.

Space Shuttle Atlantis

The first shuttle flights began in April of 1981 and continued success was achieved during the first twenty four flights. A tragic disaster occurred on the twenty fifth flight when the shuttle Challenger exploded. The problem was traced to O-ring seals in the solid rocket boosters which were affected by unusually cold temperatures on the day of the launch. Despite warning from engineers, the launch was made with disastrous results. The shuttle was immediately grounded and for almost two years additional research and testing took place to correct the problems. It was not until the fall of 1988 that shuttle flights were resumed.

Many situations arise in space that require solving unforeseen problems. The unique qualities of the human mind are the best tools for solving these problems. Space shuttle crews have met challenges on several occasions. On one Space Shuttle mission, an astronaut was sent outside the orbiter to retrieve a satellite which had not achieved its proper orbit. Because the satellite was tumbling, it was quickly determined that this method would be too dangerous. After assessing the situation, the astronauts manoeuvred the Shuttle close to the satellite. They used its remote manipulator arm to capture the satellite and bring it back into the Shuttle cargo bay. After it was repaired, they redeployed the satellite so that it could boost itself into its proper orbit. This is but one of the many possible uses of the Shuttle.

The Space Shuttle can also be used to retrieve damaged satellites and return them to Earth for repair. It can take satellites into space and launch them into orbit. Its cargo bay can be used to take the European Space-lab into space so that scientific experiments can be carried out. It can also place large observatories in space, such as the Hubble Space Telescope. It has been used in detailed mapping of the Earth as part of the [[[Shuttle Radar Topography Mission]] (SRTM). Plans for the 1990s call for using the Shuttle cargo bay to transport the basic elements of the structures for the Space Station which will be assembled in space.

Design process

In September 1966, NASA and the Air Force released a joint study concluding that a new vehicle was required to satisfy their respective future demands and that a partially reusable system would be the most cost-effective solution. The head of the NASA Office of Manned Space Flight, George Mueller, announced the plan for a reusable shuttle on August 10, 1968. NASA issued a request for proposal (RFP) for designs of the Integrated Launch and Re-entry Vehicle (ILRV), which would later become the Space Shuttle. Rather than award a contract based upon initial proposals, NASA announced a phased approach for the Space Shuttle contracting and development; Phase A was a request for studies completed by competing aerospace companies, Phase B was a competition between two contractors for a specific contract, Phase C involved designing the details of the spacecraft components, and Phase D was the production of the spacecraft.

In December 1968, NASA created the Space Shuttle Task Group to determine the optimal design for a reusable spacecraft, and issued study contracts to General Dynamics, Lockheed, McDonnell Douglas, and North American Rockwell. In July 1969, the Space Shuttle Task Group issued a report that determined the Shuttle would support short-duration crewed missions and space station, as well as the capabilities to launch, service, and retrieve satellites. The report also created three classes of a future reusable shuttle: Class I would have a reusable orbiter mounted on expendable boosters, Class II would use multiple expendable rocket engines and a single propellant tank (stage-and-a-half), and Class III would have both a reusable orbiter and a reusable booster. In September 1969, the Space Task Group, under the leadership of Vice President Spiro Agnew, issued a report calling for the development of a space shuttle to bring people and cargo to low Earth orbit (LEO), as well as a space tug for transfers between orbits and the Moon, and a reusable nuclear upper stage for deep space travel.

After the release of the Space Shuttle Task Group report, many aerospace engineers favored the Class III, fully reusable design because of perceived savings in hardware costs. Max Faget, a NASA engineer who had worked to design the Mercury capsule, patented a design for a two-stage fully recoverable system with a straight-winged orbiter mounted on a larger straight-winged booster. The Air Force Flight Dynamics Laboratory argued that a straight-wing design would not be able to withstand the high thermal and aerodynamic stresses during reentry, and would not provide the required cross-range capability. Additionally, the Air Force required a larger payload capacity than Faget's design allowed. In January 1971, NASA and Air Force leadership decided that a reusable delta-wing orbiter mounted on an expendable propellant tank would be the optimal design for the Space Shuttle.

After they established the need for a reusable, heavy-lift spacecraft, NASA and the Air Force determined the design requirements of their respective services. The Air Force expected to use the Space Shuttle to launch large satellites, and required it to be capable of lifting 29,000 kg (65,000 lb) to an eastward LEO or 18,000 kg (40,000 lb) into a polar orbit. The satellite designs also required that the Space Shuttle have a 4.6 by 18 m (15 by 60 ft) payload bay. NASA evaluated the F-1 and J-2 engines from the Saturn rockets, and determined that they were insufficient for the requirements of the Space Shuttle; in July 1971, it issued a contract to Rocketdyne to begin development on the RS-25 engine.

NASA reviewed 29 potential designs for the Space Shuttle and determined that a design with two side boosters should be used, and the boosters should be reusable to reduce costs. NASA and the Air Force elected to use solid-propellant boosters because of the lower costs and the ease of refurbishing them for reuse after they landed in the ocean. In January 1972, President Richard Nixon approved the Shuttle, and NASA decided on its final design in March. That August, NASA awarded the contract to build the orbiter to North American Rockwell, the solid-rocket booster contract to Morton Thiokol, and the external tank contract to Martin Marietta.

Development

Columbia undergoing installation of its ceramic tiles On June 4, 1974, Rockwell began construction on the first orbiter, OV-101, which would later be named Enterprise. Enterprise was designed as a test vehicle, and did not include engines or heat shielding. Construction was completed on September 17, 1976, and Enterprise was moved to the Edwards Air Force Base to begin testing. Rockwell constructed the Main Propulsion Test Article (MPTA)-098, which was a structural truss mounted to the ET with three RS-25 engines attached. It was tested at the National Space Technology Laboratory (NSTL) to ensure that the engines could safely run through the launch profile. Rockwell conducted mechanical and thermal stress tests on Structural Test Article (STA)-099 to determine the effects of aerodynamic and thermal stresses during launch and reentry.

The beginning of the development of the RS-25 Space Shuttle Main Engine was delayed for nine months while Pratt & Whitney challenged the contract that had been issued to Rocketdyne. The first engine was completed in March 1975, after issues with developing the first throttleable, reusable engine. During engine testing, the RS-25 experienced multiple nozzle failures, as well as broken turbine blades. Despite the problems during testing, NASA ordered the nine RS-25 engines needed for its three orbiters under construction in May 1978.

NASA experienced significant delays in the development of the Space Shuttle's thermal protection system. Previous NASA spacecraft had used ablative heat shields, but those could not be reused. NASA chose to use ceramic tiles for thermal protection, as the shuttle could then be constructed of lightweight aluminum, and the tiles could be individually replaced as needed. Construction began on Columbia on March 27, 1975, and it was delivered to the KSC on March 25, 1979. At the time of its arrival at the KSC, Columbia still had 6,000 of its 30,000 tiles remaining to be installed. However, many of the tiles that had been originally installed had to be replaced, requiring two years of installation before Columbia could fly.

On January 5, 1979, NASA commissioned a second orbiter. Later that month, Rockwell began converting STA-099 to OV-099, later named Challenger. On January 29, 1979, NASA ordered two additional orbiters, OV-103 and OV-104, which were named Discovery and Atlantis. Construction of OV-105, later named Endeavour, began in February 1982, but NASA decided to limit the Space Shuttle fleet to four orbiters in 1983. After the loss of Challenger, NASA resumed production of Endeavour in September 1987.

Testing

Enterprise during the Approach and Landing Tests Columbia launching on STS-1

Space Shuttle Atlantis piggybacking the Shuttle Carrier Aircraft (SCA) ferries space shuttle Atlantis back to the Kennedy Space Center after landing at NASA's Dryden Flight Research Center at Edwards Air Force Base.

After it arrived at Edwards AFB, Enterprise underwent flight testing with the Shuttle Carrier Aircraft, a Boeing 747 that had been modified to carry the orbiter. In February 1977, Enterprise began the Approach and Landing Tests and underwent captive flights, where it remained attached to the Shuttle Carrier Aircraft for the duration of the flight. On August 12, 1977, Enterprise conducted its first glide test, where it detached from the Shuttle Carrier Aircraft and landed at Edwards AFB. After four additional flights, Enterprise was moved to the Marshall Space Flight Center (MSFC) on March 13, 1978. Enterprise underwent shake tests in the Mated Vertical Ground Vibration Test, where it was attached to an external tank and solid rocket boosters, and underwent vibrations to simulate the stresses of launch. In April 1979, Enterprise was taken to the KSC, where it was attached to an external tank and solid rocket boosters, and moved to LC-39. Once installed at the launch pad, the Space Shuttle was used to verify the proper positioning of launch complex hardware. Enterprise was taken back to California in August 1979, and later served in the development of the SLC-6 at Vandenberg AFB in 1984.

On November 24, 1980, Columbia was mated with its external tank and solid-rocket boosters, and was moved to LC-39 on December 29. The first Space Shuttle mission, STS-1, would be the first time NASA performed a crewed first-flight of a spacecraft. On April 12, 1981, the Space Shuttle launched for the first time, and was piloted by John Young and Robert Crippen. During the two-day mission, Young and Crippen tested equipment on board the shuttle, and found several of the ceramic tiles had fallen off the top side of the Columbia. NASA coordinated with the Air Force to use satellites to image the underside of Columbia, and determined there was no damage. Columbia reentered the atmosphere and landed at Edwards AFB on April 14.

NASA conducted three additional test flights with Columbia in 1981 and 1982. On July 4, 1982, STS-4, flown by Ken Mattingly and Henry Hartsfield, landed on a concrete runway at Edwards AFB. President Ronald Reagan and his wife Nancy met the crew, and delivered a speech. After STS-4, NASA declared its Space Transportation System (STS) operational.

Description

The Space Shuttle was the first operational orbital spacecraft designed for reuse. Each Space Shuttle orbiter was designed for a projected lifespan of 100 launches or ten years of operational life, although this was later extended. At launch, it consisted of the orbiter, which contained the crew and payload, the external tank (ET), and the two solid rocket boosters (SRBs).

Responsibility for the Shuttle components was spread among multiple NASA field centers. The KSC was responsible for launch, landing, and turnaround operations for equatorial orbits (the only orbit profile actually used in the program). The U.S. Air Force at the Vandenberg Air Force Base was responsible for launch, landing, and turnaround operations for polar orbits (though this was never used). The Johnson Space Center (JSC) served as the central point for all Shuttle operations and the MSFC was responsible for the main engines, external tank, and solid rocket boosters. The John C. Stennis Space Center handled main engine testing, and the Goddard Space Flight Center managed the global tracking network.

Training

Shuttle Training Aircraft (STA) cockpit. The STA was a modified Grumman Gulfstream II aircraft that emulated the Space Shuttles handling. It had Space Shuttle cockpit controls on the left and airplane controls on the right.

Shuttle Mission Simulators

There were two types of Shuttle mission simulators, the fixed base and the motion base simulators. The Fixed Base Simulator (FBS) were high-detail reprductions of the flight deck and lower detail reproductions of the mid-deck. The motion base simulators were known as the Guidance and Navigation Simulator with initial focus implied by the name, before the full detail of the FBS was added. Payload control was simulated at Marshall Space Flight Center or Goddard Space Flight Center.

Shuttle Training Aircraft

The Space Shuttle lacked the power to abort an approach and "go around" for a re-try - the Shuttle behaves mostly as a glider with a steep descent profile on re-entry. This leaves no room for mistakes, and training was critical. To that end a Shuttle Training Aircraft (STA) was created by modifying an existing aircraft. The Grumman Gulfstream II was modified to simulate the Shuttle's steep approach and limited handling behaviour. The cockpit controls were split so the left hand side had the Space Shuttle interface and seating position, and the right hand side had normal airplane controls.

External resources

• Gigapan image with pan and zoom: exterior view
• Post flight presentations for all Shuttle missions: youtube playlist
• Freely downloadable (i.e. public) open-source simulation of the Space Shuttle that runs on desktop PCs. Uses aerospace research and development sim FlightGear's flight dynamics engine (JSBSim), which is used in a 2015 NASA benchmark to judge new simulation code to the standards of the space industry. Most detailed simulation of the Space Shuttle outside of NASA's internal ones Can be flown directly by Shuttle Crew Operations Manual (SCOM) and supports detailed failure simulation. Videos. (To access: install FlightGear core (~2GB download) and select NASA Space Shuttle from launcher's craft browser. Quick starts are available: In orbit, near ISS, piggyback on carrier with detached glide, middle of re-entry (TAEM), on approach to land (trainer), ready for launch with minimal work. See Shuttle manual in wiki page, FlightGear manual, Earthview orbital renderer HD textures & options.)

See also

• Buran (Wikipedia, comparison), a Space Shuttle from the USSR's Buran program, that flew 1 test-mission, and which drew on some of the NASA Space Shuttle's design.

References

Space Shuttle Missions
All Missions	STS-1 STS-2 STS-3 STS-4 STS-5 STS-6 STS-7 STS-8 STS-9 STS-41-B STS-41-C STS-41-D STS-41-G STS-51-A STS-51-C STS-51-D STS-51-I STS-51-J STS-51-L STS-26 STS-27 STS-29 STS-30 STS-34 STS-33 STS-32 STS-36 STS-31 STS-39 STS-40 STS-43 STS-44 STS-46 STS-47 STS-52 STS-55 STS-57 STS-58 STS-61 STS-63 STS-67 STS-68 STS-69 STS-70 STS-71 STS-72 STS-74 STS-75 STS-76 STS-77 STS-79 STS-81 STS-82 STS-83 STS-84 STS-85 STS-86 STS-87 STS-88 STS-89 STS-90 STS-91 STS-93 STS-94 STS-95 STS-97 STS-98 STS-99 STS-100 STS-107 STS-114 STS-121 STS-124 STS-125 STS-128 STS-129 STS-132 STS-133 STS-134 STS-135
Challenger Missions	STS-6 STS-7 STS-8 STS-41-B STS-41-C STS-41-G STS-51-A STS-51-C STS-51-I STS-51-L
Columbia Missions	STS-1 STS-2 STS-3 STS-9 STS-32 STS-35 STS-39 STS-40 STS-52 STS-62 STS-80 STS-107
Discovery Missions	STS-41-D STS-51-D STS-51-J STS-53 STS-61 STS-64 STS-70 STS-82 STS-103 STS-121 STS-114 STS-128
Atlantis Missions	STS-51-J STS-61 STS-68 STS-74 STS-79 STS-81 STS-84 STS-86 STS-101 STS-112 STS-135
Endeavour Missions	STS-49 STS-61 STS-68 STS-75 STS-77 STS-88 STS-91 STS-100 STS-108 STS-134