Space Shuttle

The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons. Major missions included launching numerous satellites and interplanetary probes,conducting space science experiments, and 37 missions constructing and servicing the International Space Station. Sony VAIO VGN-AW70B/Q Battery

A major international contribution was the Spacelab payload suite, from the ESA.

Major components included the orbiters, recoverable boosters, external tanks, payloads, and supporting infrastructure — orchestrated by thousands of people on the ground and crewed by an elite cadre of astronauts.Sony VAIO VGN-AW71JB Battery

Overview

The Space Shuttle was a partially reuseable launch system and orbital spacecraft operated by the U.S. National Aeronautics and Space Administration (NASA) for human spaceflight missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons.Sony VAIO VGN-AW72JB Battery

The first of four orbital test flights occurred in 1981 leading to operational flights beginning in 1982, all launched from the Kennedy Space Center, Florida. The system was retired from service in 2011 after 135 missions; on July 8, 2011, with Space Shuttle Atlantis performing that 135th launch - the final launch of the three-decade shuttle program.Sony VAIO VGN-AW73FB Battery

The program ended after Atlantis landed at the Kennedy Space Center on July 21, 2011. Major missions included launching numerous satellites and interplanetary probes, conducting space science experiments, and servicing and construction of space stations.Sony VAIO VGN-AW80NS Battery

Enterprise was a prototype orbiterused for atmospheric testing during development in the 1970s, and lacked engines and heat shield. Five space-worthyorbiters were built—two were destroyed in accidents and the others have been retired.

It was used for orbital space missions by NASA, the U.S. Department of Defense, the European Space Agency, Japan, and Germany.Sony VAIO VGN-AW80S Battery

The United States funded Space Transportation System (STS) development and shuttle operations except for Spacelab D1 and D2 — sponsored by West Germany and reunified Germany respectively. In addition, SL-J was partially funded by Japan.

At launch, it consisted of the "stack", including a dark orange-colored external tank (ET); two white, slender Solid Rocket Boosters (SRBs); and the Orbiter Vehicle (OV), which contained the crew and payload.Sony VAIO VGN-AW80US Battery

Some payloads were launched into higher orbits with either of two different booster stages developed for the STS (single-stage Payload Assist Module or two-stage Inertial Upper Stage). The Space Shuttle was stacked in the Vehicle Assembly Building and the stack mounted on a mobile launch platform held down by four explosive bolts on each SRB which are detonated at launch.Sony VAIO VGN-AW81DS Battery

The shuttle stack launched vertically like a conventional rocket. It lifted off under the power of its two SRBs and threemain engines, which were fueled by liquid hydrogen and liquid oxygen from the external tank. The Space Shuttle had a two-stage ascent. The SRBs provided additional thrust during liftoff and first-stage flight.Sony VAIO VGN-AW81JS Battery

About two minutes after liftoff, explosive bolts were fired, releasing the SRBs, which then parachuted into the ocean, to be retrieved by ships for refurbishment and reuse. The shuttle orbiter and external tank continued to ascend on an increasingly horizontal flight path under power from its main engines. Sony VAIO VGN-AW81YS Battery

Upon reaching 17,500 mph (7.8 km/s), necessary for low Earth orbit, the main engines were shut down. The external tank was then jettisoned to burn up in the atmosphere. After jettisoning the external tank, the orbital maneuvering system (OMS) engines were used to adjust the orbit.Sony VAIO VGN-AW82DS Battery

The orbiter carried people and payload such as satellites or space station parts into low Earth orbit, into the Earth's upper atmosphere or thermosphere. Usually, five to seven crew members rode in the orbiter. Two crew members, the commander and pilot, were sufficient for a minimal flight, as in the first four "test" flights, STS-1 through STS-4. Sony VAIO VGN-AW82JS Battery

The typical payload capacity was about 22,700 kilograms (50,000 lb), but could be increased depending on the choice of launch configuration. The orbiter carried its payload in a large cargo bay with doors that opened along the length of its top, a feature which made the Space Shuttle unique among spacecraft. Sony VAIO VGN-AW82YS Battery

This feature made possible the deployment of large satellites such as the Hubble Space Telescope, and also the capture and return of large payloads back to Earth.

When the orbiter's space mission was complete, it fired its OMS thrusters to drop out of orbit and re-enter the lower atmosphere.Sony VAIO VGN-AW83FS Battery

During descent, the orbiter passed through different layers of the atmosphere and decelerates fromhypersonic speed primarily by aerobraking. In the lower atmosphere and landing phase, it was more like a glider but withreaction control system (RCS) thrusters and fly-by wire-controlled hydraulically-actuated flight surfaces controlling its descent. Sony VAIO VGN-AW83GS Battery

It landed on a long runway as a spaceplane. The aerodynamic shape was a compromise between the demands of radically different speeds and air pressures during re-entry, hypersonic flight, and subsonic atmospheric flight. As a result, the orbiter had a relatively high sink rate at low altitudes, Sony VAIO VGN-AW83HS Battery

and it transitioned during re-entry from using RCS thrusters at very high altitudes to flight surfaces in the lower atmosphere.

Early history

The formal design of what became the Space Shuttle began with "Phase A" contract design studies issued in the late 1960s.Sony VAIO VGN-AW90NS Battery

However, conceptualization began two decades earlier, before the Apollo program of the 1960s. One of the places the concept of a spacecraft returning from space to a horizontal landing originated was within NACA, in 1954, in the form of anaeronautics research experiment later named the X-15. The NACA proposal was submitted by Walter Dornberger.Sony VAIO VGN-AW90S Battery

In 1958, the X-15 concept further developed into proposal to launch a X-15 into space, and another X-series spaceplaneproposal, called the X-20, which was not constructed, as well as variety of aerospace plane concepts and studies. Neil Armstrong was selected to pilot both the X-15 and the X-20. Sony VAIO VGN-AW90US Battery

Though the X-20 was not built, another spaceplane similar to the X-20 was built several years later and delivered to NASA in January 1966 called the HL-10 ("HL" indicated "horizontal landing").

In the mid-1960s, the US Air Force conducted a series of classified studies on next-generation space transportation systems and concluded that semi-reusable designs were the cheapest choice. Sony VAIO VGN-AW91CDS Battery

It proposed a development program with an immediate start on a "Class I" vehicle with expendable boosters, followed by slower development of a "Class II" semi-reusable design and perhaps a "Class III" fully reusable design later. In 1967, George Mueller held a one-day symposium at NASA headquarters to study the options. Sony VAIO VGN-AW91CJS Battery

Eighty people attended and presented a wide variety of designs, including earlier Air Force designs as the Dyna-Soar (X-20).

In 1968, NASA officially began work on what was then known as the Integrated Launch and Re-entry Vehicle (ILRV). At the same time, NASA held a separate Space Shuttle Main Engine (SSME) competition.Sony VAIO VGN-AW91CYS Battery

NASA offices in Houston and Huntsville jointly issued a Request for Proposal (RFP) for ILRV studies to design a spacecraft that could deliver a payload to orbit but also re-enter the atmosphere and fly back to Earth. For example, one of the responses was for a two-stage design, featuring a large booster and a small orbiter, called the DC-3, one of several Phase A shuttle designs.Sony VAIO VGN-AW91DS Battery

After the aforementioned "Phase A" studies, B, C, and D phases progressively evaluated in-depth designs up to 1972. In the final design, the bottom stage was recoverable solid rocket boosters, and the top stage used an expendable external tank.

In 1969, President Richard Nixon decided to support proceeding with Space Shuttle development. Sony VAIO VGN-AW91JS Battery

A series of development programs and analysis refined the basic design, prior to full development and testing. In August 1973, the X-24B proved that an unpowered spaceplane could re-enter Earth's atmosphere for a horizontal landing.

Across the Atlantic, European ministers met in Belgium in 1973 to authorize Western Europe's manned orbital project and its main contribution to Space Shuttle — the Spacelab program.Sony VAIO VGN-AW91YS Battery

Spacelab would provide a multi-disciplinary orbital space laboratory and additional space equipment for the Shuttle.

Description

The Space Shuttle was the first operational orbital spacecraft designed for reuse. It carried different payloads to low Earth orbit, provided crew rotation for the International Space Station (ISS), and performed servicing missions.Sony VAIO VGN-AW92CDS Battery

The orbiter could also recover satellites and other payloads from orbit and return them to Earth. Each Shuttle was designed for a projected lifespan of 100 launches or ten years of operational life, although this was later extended. The person in charge of designing the STS wasMaxime Faget, who had also overseen the Mercury, Gemini, and Apollo spacecraft designs.Sony VAIO VGN-AW92CJS Battery

The crucial factor in the size and shape of the Shuttle Orbiter was the requirement that it be able to accommodate the largest planned commercial and military satellites, and have the cross-range recovery range to meet the requirement for classified USAF missions for a once-around abort from a launch to apolar orbit. Sony VAIO VGN-AW92CYS Battery

Factors involved in opting for solid rockets and an expendable fuel tank included the desire of the Pentagon to obtain a high-capacity payload vehicle for satellite deployment, and the desire of the Nixon administration to reduce the costs of space exploration by developing a spacecraft with reusable components.Sony VAIO VGN-AW92DS Battery

Each Space Shuttle is a reusable launch system that is composed of three main assemblies: the reusable Orbiter Vehicle (OV), the expendable external tank (ET), and the two reusable solid rocket boosters (SRBs).[19] Only the orbiter entered orbit shortly after the tank and boosters are jettisoned. Sony VAIO VGN-AW92JS Battery

The vehicle was launched vertically like a conventional rocket, and the orbiter glided to a horizontal landing like an airplane, after which it was refurbished for reuse. The SRBs parachuted to splashdown in the ocean where they were towed back to shore and refurbished for later shuttle missions.Sony VAIO VGN-AW92YS Battery

Five space-worthy orbiters were built: Columbia (OV-102), Challenger (OV-099), Discovery (OV-103), Atlantis (OV-104), andEndeavour (OV-105). A mock-up, Inspiration (OV-100), currently stands at the entrance to the Astronaut Hall of Fame.Sony VAIO VGN-AW93FS Battery

An additional craft, Enterprise (OV-101), was not built for orbital space flight, and was used only for testing gliding and landing. Enterprisewas originally intended to be made fully space-worthy after use for the approach and landing test (ALT) program, but it was found more economical to upgrade the structural test article STA-099 into orbiter Challenger (OV-099).Sony VAIO VGN-AW93GS Battery

Challenger disintegrated 73 seconds after launch in 1986, and Endeavour was built as a replacement for Challenger from structural spare components. Columbiabroke apart during re-entry in 2003. Building Space Shuttle Endeavour cost about US$1.7 billion. One Space Shuttle launch costs around $450 million.Sony VAIO VGN-AW93HS Battery

Roger A. Pielke, Jr. has estimated that the Space Shuttle program has cost about US$170 billion (2008 dollars) through early 2008. This works out to an average cost per flight of about US$1.5 billion. However, two missions were paid for by Germany, SpacelabD1 and D2 (D for Deutschland) with a payload control center in Oberpfaffenhofen, Germany.Sony VAIO VGN-AW93ZFS Battery

D1 was the first time that control of a manned STS mission payload was not in U.S. hands.

At times, the orbiter itself was referred to as the Space Shuttle. Technically, this was a slight misnomer, as the actual "Space Transportation System" (Space Shuttle) was the combination of the orbiter, the external tank, and the two solid rocket boosters.Sony VAIO VGN-AW93ZGS Battery

Combined, these were referred to as the "stack"; the components were assembled in the Vehicle Assembly Building, originally built to assemble the Apollo Saturn V rocket.

Responsibility for the shuttle components was spread among multiple NASA field centers.Sony VAIO VGN-AW93ZHS Battery

The Kennedy Space Center was responsible for launch, landing and turnaround operations for equatorial orbits (the only orbit profile actually used in the program), the US Air Force at the Vandenberg Air Force Base was responsible for launch, landing and turnaround operations for polar orbits (though this was never used),Sony VAIO VGN-BZ11EN Battery

the Johnson Space Center served as the central point for all shuttle operations, theMarshall Space Flight Center 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. Sony VAIO VGN-BZ11MN Battery

Orbiter vehicle

The orbiter resembles a conventional aircraft, with double-delta wings swept 81° at the inner leading edge and 45° at the outer leading edge. Its vertical stabilizer's leading edge is swept back at a 50° angle. Sony VAIO VGN-BZ11XN Battery

The four elevons, mounted at the trailing edge of the wings, and the rudder/speed brake, attached at the trailing edge of the stabilizer, with the body flap, controlled the orbiter during descent and landing.

The orbiter's payload bay measures 15 by 60 feet (4.6 by 18 m), comprising most of the fuselage.Sony VAIO VGN-BZ12VN Battery

Information declassified in 2011 showed that the payload bay was designed specifically to accommodate the KH-9 HEXAGON spy satellite operated by the National Reconnaissance Office. Two mostly symmetrical lengthwise payload bay doors hinged on either side of the bay comprise its entire top. Sony VAIO VGN-BZ12XN Battery

Payloads are generally loaded horizontally into the bay while the orbiter is oriented vertically on the launch pad and unloaded vertically in the near-weightless orbital environment by the orbiter's robotic remote manipulator arm (under astronaut control), EVA astronauts, or under the payloads' own power (as for satellites attached to a rocket "upper stage" for deployment.)Sony VAIO VGN-BZ31VT Battery

Three Space Shuttle main engines (SSMEs) are mounted on the orbiter's aft fuselage in a triangular pattern. The engine nozzles can swivel 10.5 degrees up and down, and 8.5 degrees from side to side during ascent to change the direction of their thrust to steer the shuttle. Sony VAIO VGN-BZ31XT Battery

The orbiter structure is made primarily from aluminum alloy, although the engine structure is made primarily fromtitanium alloy.

External tank

The main function of the Space Shuttle external tank was to supply the liquid oxygen and hydrogen fuel to the main engines.Sony VAIO VGN-BZ560 Battery

It was also the backbone of the launch vehicle, providing attachment points for the two Solid Rocket Boosters and the Orbiter. The external tank was the only part of the shuttle system that was not reused. Although the external tanks were always discarded, it was possible to take them into orbit and re-use them (such as for incorporation into a space station).Sony VAIO VGN-BZ560N24 Battery

Solid rocket boosters

Two solid rocket boosters (SRBs) each provided 12.5 million newtons (2.8 million lbf) of thrust at liftoff,[29] which was 83% of the total thrust needed for liftoff. The SRBs were jettisoned two minutes after launch at a height of about 150,000 feet (46 km), and then deployed parachutes and landed in the ocean to be recovered.Sony VAIO VGN-BZ560N30 Battery

The SRB cases were made of steel about ½ inch (13 mm) thick.The Solid Rocket Boosters were re-used many times; the casing used in Ares I engine testing in 2009 consisted of motor cases that had been flown, collectively, on 48 shuttle missions, including STS-1.Sony VAIO VGN-BZ560P Battery

Orbiter add-ons

The orbiter could be used in conjunction with a variety of add-ons depending on the mission. This has included orbital laboratories (Spacelab, Spacehab), boosters for launching payloads farther into space (Inertial Upper Stage, Payload Assist Module),Sony VAIO VGN-BZ560P20 Battery

and other functions, such as provided by Extended Duration Orbiter, Multi-Purpose Logistics Modules, or Canadarm (RMS). An upper-stage called Transfer Orbit Stage (Orbital Science Corp. TOS-21) was also used once.Other types of systems and racks were part of the modular Spacelab system — pallets, igloo, IPS, etc., which also supported special missions such as SRTM.Sony VAIO VGN-BZ560P22 Battery

Spacelab

A major component of the Space Shuttle Program was Spacelab, primarily contributed by a consortium of European countries, and operated in conjunction with the United States and international partners. Supported by a modular system of pressurized modules, pallets, and systems, Spacelab missions executed on multidisciplinary science, orbital logistics, international cooperation.Sony VAIO VGN-BZ560P28 Battery

Over 29 missions flew on subjects ranging from astronomy, microgravity, radar, and life sciences, to name a few. Spacelab hardware also supported missions such as Hubble (HST) servicing and space station resupply. STS-2 and STS-3 provided testing, and the first full mission was Spacelab-1 (STS-9) launched on November 28, 1983.Sony VAIO VGN-BZ560P30 Battery

Spacelab formally began in 1973, after a meeting in Brussels, Belgium, by European heads of state. Within the decade, Spacelab would go into orbit and provide not only Europe, but also the United States, with an orbital workshop and hardware system. International cooperation, science, and exploration were realized on Spacelab.Sony VAIO VGN-BZ560P34 Battery

Flight systems

The shuttle was one of the earliest craft to use a computerized fly-by-wire digital flight control system. This means no mechanical or hydraulic linkages connected the pilot's control stick to the control surfaces or reaction control system thrusters.Sony VAIO VGN-BZ561 Battery

A concern with digital fly-by-wire systems is reliability. Considerable research went into the shuttle computer system. The shuttle used five identical redundant IBM 32-bit general purpose computers (GPCs), model AP-101, constituting a type of embedded system. Four computers ran specialized software called the Primary Avionics Software System (PASS). Sony VAIO VGN-BZ561N20 Battery

A fifth backup computer ran separate software called the Backup Flight System (BFS). Collectively they were called the Data Processing System (DPS).

The design goal of the shuttle's DPS was fail-operational/fail-safe reliability. After a single failure, the shuttle could still continue the mission. After two failures, it could still land safely.Sony VAIO VGN-BZ561P20 Battery

The four general-purpose computers operated essentially in lockstep, checking each other. If one computer failed, the three functioning computers "voted" it out of the system. This isolated it from vehicle control. If a second computer of the three remaining failed, the two functioning computers voted it out. Sony VAIO VGN-BZ562P Battery

In the unlikely case of two out of four computers simultaneously failed (a two-two split), one group was to be picked at random.

The Backup Flight System (BFS) was separately developed software running on the fifth computer, used only if the entire four-computer primary system failed. Sony VAIO VGN-BZ563P Battery

The BFS was created because although the four primary computers were hardware redundant, they all ran the same software, so a generic software problem could crash all of them. Embedded system avionic software was developed under totally different conditions from public commercial software: the number of code lines was tiny compared to a public commercial software,Sony VAIO VGN-BZAAFS Battery

changes were only made infrequently and with extensive testing, and many programming and test personnel worked on the small amount of computer code. However, in theory it could have still failed, and the BFS existed for that contingency. While the BFS could run in parallel with PASS, the BFS never engaged to take over control from PASS during any shuttle mission.Sony VAIO VGN-BZAAHS Battery

The software for the shuttle computers was written in a high-level language called HAL/S, somewhat similar to PL/I. It is specifically designed for a real time embedded system environment.

The IBM AP-101 computers originally had about 424 kilobytes of magnetic core memory each. The CPU could process about 400,000 instructions per second. They had no hard disk drive, and load software from magnetic tape cartridges.Sony VAIO VGN-BZAANS Battery

In 1990, the original computers were replaced with an upgraded model AP-101S, which had about 2.5 times the memory capacity (about 1 megabyte) and three times the processor speed (about 1.2 million instructions per second). The memory was changed from magnetic core to semiconductor with battery backup.Sony VAIO VGN-BZAAPS Battery

Early shuttle missions, starting in November 1983, took along the GRiD Compass, arguably one of the first laptop computers. The GRiD was given the name SPOC, for Shuttle Portable Onboard Computer. Use on the Shuttle required both hardware and software modifications which were incorporated into later versions of the commercial product.Sony VAIO VGN-CR11H/B Battery

It was used to monitor and display the Shuttle's ground position, path of the next two orbits, show where the shuttle had line of sight communications with ground stations, and determine points for location-specific observations of the Earth. The Compass sold poorly, as it cost at least US$8000, but it offered unmatched performance for its weight and size.Sony VAIO VGN-CR11S/L Battery

NASA was one of its main customers.

Orbiter markings and insignia

The typeface used on the Space Shuttle Orbiter is Helvetica. On the side of the shuttle between the cockpit windows and the cargo bay doors is the name of the orbiter. Underneath the rear of the cargo bay doors have been various NASA insignia, the text "United States" and a flag of the United States.Sony VAIO VGN-CR11S/P Battery

On STS-1, Space Shuttle Columbia, being the first orbiter built, had a flag of the United States on the left wing and a "USA" in bold on the left wing and the word "Columbia" was on the Payload Bay Doors.It remained there until STS-9, after which it was moved to the usual position on the other orbiters.Sony VAIO VGN-CR11S/W Battery

Space Shuttle Challengerwore the letters "USA" and the flag on the left wing, with the NASA worm lettering and the word "Challenger" below it on the right wing. Challenger also had a different hatch tile pattern. As a result of Challenger early loss, it is the only orbiter never to wear the "meatball" logo on its left wing. Sony VAIO VGN-CR11Z/R Battery

The subsequent orbiters benefited from technological advances in tile positioning and were largely similar.

Upgrades

The Space Shuttle was initially developed in the 1970s, but received many upgrades and modifications afterward for improvements ranging from performance and reliability to safety.Sony VAIO VGN-CR120E/L Battery

Internally, the shuttle remained largely similar to the original design, with the exception of the improved avionics computers. In addition to the computer upgrades, the original analog primary flight instruments were replaced with modern full-color, flat-panel display screens, similar to those of contemporary airliners like theAirbus A380 and Boeing 777. Sony VAIO VGN-CR120E/P Battery

This was called a glass cockpit. With the coming of the ISS, the orbiter's internal airlocks were replaced with external docking systems to allow for a greater amount of cargo to be stored on the shuttle's mid-deck during station resupply missions.

The Space Shuttle Main Engines (SSMEs) had several improvements to enhance reliability and power. Sony VAIO VGN-CR120E/R Battery

This explains phrases such as "Main engines throttling up to 104 percent." This did not mean the engines were being run over a safe limit. The 100 percent figure was the original specified power level. During the lengthy development program, Rocketdyne determined the engine was capable of safe reliable operation at 104 percent of the originally specified thrust. Sony VAIO VGN-CR120E/W Battery

NASA could have rescaled the output number, saying in essence 104 percent is now 100 percent. To clarify this would have required revising much previous documentation and software, so the 104 percent number was retained. SSME upgrades were denoted as "block numbers", such as block I, block II, and block IIA. Sony VAIO VGN-CR125E/B Battery

The upgrades improved engine reliability, maintainability and performance. The 109% thrust level was finally reached in flight hardware with the Block II engines in 2001. The normal maximum throttle was 104 percent, with 106 percent or 109 percent used for mission aborts.Sony VAIO VGN-CR13/B Battery

For the first two missions, STS-1 and STS-2, the external tank was painted white to protect the insulation that covers much of the tank, but improvements and testing showed that it was not required. The weight saved by not painting the tank resulted in an increase in payload capability to orbit.Sony VAIO VGN-CR13/L Battery

Additional weight was saved by removing some of the internal "stringers" in the hydrogen tank that proved unnecessary. The resulting "light-weight external tank" has been used on the vast majority of shuttle missions. STS-91 saw the first flight of the "super light-weight external tank".Sony VAIO VGN-CR13/P Battery

This version of the tank is made of the 2195 aluminum-lithium alloy. It weighs 3.4 metric tons (7,500 lb) less than the last run of lightweight tanks. As the shuttle was not flown unmanned, each of these improvements was "tested" on operational flights.

The SRBs (Solid Rocket Boosters) underwent improvements as well. Design engineers added a third O-ring seal to the joints between the segments after the 1986 Space Shuttle Challenger disaster.Sony VAIO VGN-CR13/R Battery

Several other SRB improvements were planned to improve performance and safety, but never came to be. These culminated in the considerably simpler, lower cost, probably safer and better-performing Advanced Solid Rocket Booster. These rockets entered production in the early to mid-1990s to support the Space Station, but were later canceled to save money after the expenditure of $2.2 billion.Sony VAIO VGN-CR13/W Battery

The loss of the ASRB program resulted in the development of the Super LightWeight external Tank (SLWT), which provided some of the increased payload capability, while not providing any of the safety improvements. In addition, the Air Force developed their own much lighter single-piece SRB design using a filament-wound system, but this too was canceled.Sony VAIO VGN-CR131E/L Battery

STS-70 was delayed in 1995, when woodpeckers bored holes in the foam insulation of Discovery's external tank. Since then, NASA has installed commercial plastic owl decoys and inflatable owl balloons which had to be removed prior to launch. The delicate nature of the foam insulation had been the cause of damage to the Thermal Protection System,Sony VAIO VGN-CR13G Battery

the tile heat shield and heat wrap of the orbiter. NASA remained confident that this damage, while it was the primary cause of the Space Shuttle Columbia disaster on February 1, 2003, would not jeopardize the completion the International Space Station (ISS) in the projected time allotted.Sony VAIO VGN-CR13G/B Battery

A cargo-only, unmanned variant of the shuttle was variously proposed and rejected since the 1980s. It was called the Shuttle-C, and would have traded re-usability for cargo capability, with large potential savings from reusing technology developed for the Space Shuttle. Sony VAIO VGN-CR13G/L Battery

Another proposal was to convert the payload bay into a passenger area, with proposals ranging from 30 to 74 seats, three days in orbit, and 1.5 million USD a seat.

On the first four shuttle missions, astronauts wore modified US Air Force high-altitude full-pressure suits, which included a full-pressure helmet during ascent and descent. Sony VAIO VGN-CR13G/P Battery

From the fifth flight, STS-5, until the loss of Challenger, one-piece light blue nomexflight suits and partial-pressure helmets were worn. A less-bulky, partial-pressure version of the high-altitude pressure suits with a helmet was reinstated when shuttle flights resumed in 1988. Sony VAIO VGN-CR13G/R Battery

The Launch-Entry Suit ended its service life in late 1995, and was replaced by the full-pressure Advanced Crew Escape Suit (ACES), which resembled the Gemini space suit in design, but retained the orange color of the Launch-Entry Suit.

To extend the duration that orbiters could stay docked at the ISS, the Station-to-Shuttle Power Transfer System (SSPTS) was installed.Sony VAIO VGN-CR13G/W Battery

The SSPTS allowed these orbiters to use power provided by the ISS to preserve their consumables. The SSPTS was first used successfully on STS-118.

Launch

All Space Shuttle missions were launched from Kennedy Space Center (KSC). The weather criteria used for launch included, but were not limited to: precipitation, temperatures, cloud cover, lightning forecast, wind, and humidity.Sony VAIO VGN-CR13T/L Battery

The shuttle was not launched under conditions where it could have been struck by lightning. Aircraft are often struck by lightning with no adverse effects because the electricity of the strike is dissipated through its conductive structure and the aircraft is not electrically grounded.Sony VAIO VGN-CR13T/P Battery

Like most jet airliners, the shuttle was mainly constructed of conductive aluminum, which would normally shield and protect the internal systems. However, upon liftoff the shuttle sent out a long exhaust plume as it ascended, and this plume could have triggered lightning by providing a current path to ground. Sony VAIO VGN-CR13T/R Battery

The NASA Anvil Rule for a shuttle launch stated that an anvil cloudcould not appear within a distance of 10 nautical miles. The Shuttle Launch Weather Officer monitored conditions until the final decision to scrub a launch was announced. Sony VAIO VGN-CR13T/W Battery

In addition, the weather conditions had to be acceptable at one of the Transatlantic Abort Landing sites (one of several Space Shuttle abort modes) to launch as well as the solid rocket booster recovery area.While the shuttle might have safely endured a lightning strike, a similar strike caused problems on Apollo 12, so for safety NASAchose not to launch the shuttle if lightning was possible (NPR8715.5).Sony VAIO VGN-CR15/B Battery

Historically, the Shuttle was not launched if its flight would run from December to January (a year-end rollover or YERO). Its flight software, designed in the 1970s, was not designed for this, and would require the orbiter's computers be reset through a change of year, which could cause a glitch while in orbit. Sony VAIO VGN-CR150E/B Battery

In 2007, NASA engineers devised a solution so Shuttle flights could cross the year-end boundary.

On the day of a launch, after the final hold in the countdown at T-minus 9 minutes, the Shuttle went through its final preparations for launch, and the countdown was automatically controlled by the Ground Launch Sequencer (GLS), Sony VAIO VGN-CR190 Battery

software at the Launch Control Center, which stopped the count if it sensed a critical problem with any of the Shuttle's onboard systems. The GLS handed off the count to the Shuttle's on-board computers at T minus 31 seconds, in a process called auto sequence start.Sony VAIO VGN-CR190E/L Battery

At T-minus 16 seconds, the massive sound suppression system (SPS) began to drench the Mobile Launcher Platform (MLP) and SRB trenches with 350,000 US gallons (1,300 m3) of water to protect the Orbiter from damage by acoustical energy and rocket exhaust reflected from the flame trench and MLP during lift off (NASA article).Sony VAIO VGN-CR190E/P Battery

At T-minus 10 seconds, hydrogen igniters were activated under each engine bell to quell the stagnant gas inside the cones before ignition. Failure to burn these gases could trip the onboard sensors and create the possibility of an overpressure and explosion of the vehicle during the firing phase.Sony VAIO VGN-CR190E/R Battery

The main engine turbopumps also began charging the combustion chambers with liquid hydrogen and liquid oxygen at this time. The computers reciprocated this action by allowing the redundant computer systems to begin the firing phase.

The three main engines (SSMEs) started at T-minus 6.6 seconds. The main engines ignited sequentially via the shuttle's general purpose computers (GPCs) at 120 millisecond intervals.Sony VAIO VGN-CR190E/W Battery

The GPCs required that the engines reach 90 percent of their rated performance to complete the final gimbal of the main engine nozzles to liftoff configuration. When the SSMEs started, water from the sound suppression system flashed into a large volume of steam that shot southward. Sony VAIO VGN-CR19VN/B Battery

All three SSMEs had to reach the required 100 percent thrust within three seconds, otherwise the onboard computers would initiate an RSLS abort. If the onboard computers verified normal thrust buildup, at T minus 0 seconds, the 8 pyrotechnic nuts holding the vehicle to the pad were detonated and theSRBs were ignited. Sony VAIO VGN-CR19XN/B Battery

At this point the vehicle was committed to liftoff, as the SRBs could not be turned off once ignited.The plume from the solid rockets exited the flame trench in a northward direction at near the speed of sound, often causing a rippling of shockwaves along the actual flame and smoke contrails.Sony VAIO VGN-CR20 Battery

At ignition, the GPCs mandated the firing sequences via the Master Events Controller, a computer program integrated with the shuttle's four redundant computer systems. There were extensive emergency procedures (abort modes) to handle various failure scenarios during ascent. Sony VAIO VGN-CR21/B Battery

Many of these concerned SSME failures, since that was the most complex and highly stressed component. After the Challenger disaster, there were extensive upgrades to the abort modes.

After the main engines started, but while the solid rocket boosters were still bolted to the pad, Sony VAIO VGN-CR21E/L Battery

the offset thrust from the Shuttle's three main engines caused the entire launch stack (boosters, tank and shuttle) to pitch down about 2 m at cockpit level. This motion was called the "nod", or "twang" in NASA jargon. As the boosters flexed back into their original shape, the launch stack pitched slowly back upright.Sony VAIO VGN-CR21E/P Battery

This took approximately six seconds. At the point when it was perfectly vertical, the boosters ignited and the launch commenced. The Johnson Space Center's Mission Control Center assumed control of the flight once the SRBs had cleared the launch tower.Sony VAIO VGN-CR21E/W Battery

Shortly after clearing the tower, the Shuttle began a combined roll, pitch and yaw maneuver that positioned the orbiter head down, with wings level and aligned with the launch pad. The Shuttle flew upside down during the ascent phase. This orientation allowed a trim angle of attack that was favorable for aerodynamic loads during the region of high dynamic pressure,Sony VAIO VGN-CR21S/L Battery

resulting in a net positive load factor, as well as providing the flight crew with use of the ground as a visual reference. The vehicle climbed in a progressively flattening arc, accelerating as the weight of the SRBs and main tank decreased. To achieve low orbit requires much more horizontal than vertical acceleration. Sony VAIO VGN-CR21S/P Battery

This was not visually obvious, since the vehicle rose vertically and was out of sight for most of the horizontal acceleration. The near circular orbital velocity at the 380 kilometers (236 mi) altitude of the International Space Station is 7.68 kilometers per second 27,650 km/h (17,180 mph), roughly equivalent to Mach 23 at sea level. Sony VAIO VGN-CR21S/W Battery

As the International Space Station orbits at an inclination of 51.6 degrees, the Shuttle had to set its inclination to the same value to rendezvous with the station.

Around a point called Max Q, where the aerodynamic forces are at their maximum, the main engines were temporarily throttled back to 72 percent to avoid overspeedingand hence overstressing the Shuttle, particularly in vulnerable areas such as the wings. Sony VAIO VGN-CR21Z/N Battery

At this point, a phenomenon known as the Prandtl-Glauert singularityoccurred, where condensation clouds formed during the vehicle's transition to supersonic speed. At T+70 seconds, the main engines throttled up to their maximum cruise thrust of 104% rated thrust.Sony VAIO VGN-CR21Z/R Battery

At T+126 seconds after launch, explosive bolts released the SRBs and small separation rockets pushed them laterally away from the vehicle. The SRBs parachuted back to the ocean to be reused. The Shuttle then began accelerating to orbit on the main engines. Sony VAIO VGN-CR220E/R Battery

The vehicle at that point in the flight had a thrust-to-weight ratio of less than one – the main engines actually had insufficient thrust to exceed the force of gravity, and the vertical speed given to it by the SRBs temporarily decreased. However, as the burn continued, the weight of the propellant decreased and the thrust-to-weight ratio exceeded 1 again and the ever-lighter vehicle then continued to accelerate towards orbit.Sony VAIO VGN-CR23/B Battery

The vehicle continued to climb and take on a somewhat nose-up angle to the horizon – it used the main engines to gain and then maintain altitude while it accelerated horizontally towards orbit. At about five and three-quarter minutes into ascent, the orbiter's direct communication links with the ground began to fade, at which point it rolled heads up to reroute its communication links to the Tracking and Data Relay Satellite system.Sony VAIO VGN-CR23/L Battery

Finally, in the last tens of seconds of the main engine burn, the mass of the vehicle was low enough that the engines had to be throttled back to limit vehicle acceleration to 3 g (29.34 m/s²), largely for astronaut comfort. At approximately eight minutes post launch, the main engines were shut down.Sony VAIO VGN-CR23/N Battery

The main engines were shut down before complete depletion of propellant, as running dry would have destroyed the engines. The oxygen supply was terminated before the hydrogen supply, as the SSMEs reacted unfavorably to other shutdown modes. (Liquid oxygen has a tendency to react violently, and supports combustion when it encounters hot engine metal.)Sony VAIO VGN-CR23/P Battery

The external tank was released by firing explosive bolts, largely burning up in the atmosphere, though some fragments fell into the ocean, in either the Indian Ocean or the Pacific Ocean depending on launch profile. The sealing action of the tank plumbing and lack of pressure relief systems on the external tank helped it break up in the lower atmosphere. Sony VAIO VGN-CR23/R Battery

After the foam burned away during reentry, the heat caused a pressure buildup in the remaining liquid oxygen and hydrogen until the tank exploded. This ensured that any pieces that fell back to Earth were small.

To prevent the shuttle from following the external tank back into the lower atmosphere, the Orbital maneuvering system (OMS) engines were fired to raise the perigee higher into the upper atmosphere.Sony VAIO VGN-CR23/W Battery

On some missions (e.g., missions to the ISS), the OMS engines were also used while the main engines were still firing. The reason for putting the orbiter on a path that brought it back to Earth was not just for external tank disposal but also one of safety: if the OMS malfunctioned, or the cargo bay doors could not open for some reason, the shuttle was already on a path to return to earth for an emergency abort landing.Sony VAIO VGN-CR240E/B Battery

Ascent tracking

The shuttle was monitored throughout its ascent for short range tracking (10 seconds before liftoff through 57 seconds after), medium range (7 seconds before liftoff through 110 seconds after) and long range (7 seconds before liftoff through 165 seconds after).Sony VAIO VGN-CR240N/B Battery

Short range cameras included 22 16mm cameras on the Mobile Launch Platform and 8 16mm on the Fixed Service Structure, 4 high speed fixed cameras located on the perimeter of the launch complex plus and additional 42 fixed cameras with 16mm motion picture film. Sony VAIO VGN-CR25G/N Battery

Medium range cameras included remotely operated tracking cameras at the launch complex plus 6 sites along the immediate coast north and south of the launch pad, each with 800mm lens and high speed cameras running 100 feet per second. These cameras ran for only 4–10 seconds due to limitations in the amount of film available.Sony VAIO VGN-CR290EAL Battery

Long range cameras included those mounted on the External Tank, SRBs and orbiter itself which streamed live video back to the ground providing valuable information about any debris falling during ascent. Long range tracking cameras with 400-inch film and 200-inch video lenses were operated by a photographer at Sony VAIO VGN-CR290EAN Battery

Playalinda Beach as well as 9 other sites from 38 miles north at the Ponce Inlet to 23 miles south to Patrick Air Force Base (PAFB) and additional mobile optical tracking camera was stationed on Merritt Island during launches. A total of 10 HD cameras were used both for ascent information for engineers and broadcast feeds to networks such as Sony VAIO VGN-CR290EAP Battery

NASA TV and HDNet The number of cameras significantly increased and numerous existing cameras were upgraded at the recommendation of the Columbia Accident Investigation Board to provide better information about the debris during launch. Debris was also tracked using a pair of WeibelContinuous Pulse Doppler X-band radars, Sony VAIO VGN-CR290EAR Battery

one on board the SRB recovery ship MV Liberty Star positioned north east of the launch pad and on a ship positioned south of the launch pad. Additionally, during the first 2 flights following the loss of Columbia and her crew, a pair of NASA WB-57 reconnaissance aircraft equipped with HD Video and Infrared flew at 60,000 feet (18,000 m) to provide additional views of the launch ascent.Sony VAIO VGN-CR290EAW Battery

Kennedy Space Center also invested nearly $3 million in improvements to the digital video analysis systems in support of debris tracking.

In orbit

Once in orbit, the Shuttle usually flew at an altitude of 200 miles (321.9 km), and occasionally as high as 400 miles.Sony VAIO VGN-CR29XN/B Battery

In the 1980s and 1990s, many flights involved space science missions on the NASA/ESA Spacelab, or launching various types of satellites and science probes. By the 1990s and 2000s the focus shifted more to servicing space stations, with fewer satellite launches. Sony VAIO VGN-CR305E/RC Battery

Most missions involved staying in orbit several days to two weeks, although longer missions were possible with the Extended Duration Orbiter add-on or when attached to a space station.

Almost the entire Space Shuttle re-entry procedure, except for lowering the landing gear and deploying the air data probes, were normally performed under computer control.Sony VAIO VGN-CR31S/D Battery

However, the re-entry could be flown entirely manually if an emergency arose. The approach and landing phase could be controlled by the autopilot, but was usually hand flown.Sony VAIO VGN-CR323/W Battery

Re-entry and landing

The vehicle began re-entry by firing the Orbital maneuvering system engines, while flying upside down, backside first, in the opposite direction to orbital motion for approximately three minutes, which reduced the shuttle's velocity by about 200 mph (322 km/h).Sony VAIO VGN-CR33 Battery

The resultant slowing of the Shuttle lowered its orbital perigee down into the upper atmosphere. The shuttle then flipped over, by pushing its nose down (which was actually "up" relative to the Earth, because it was flying upside down). This OMS firing was done roughly halfway around the globe from the landing site.Sony VAIO VGN-CR382 Battery

The vehicle started encountering more significant air density in the lower thermosphere at about 400,000 ft (120 km), at aroundMach 25, 8,200 m/s (30,000 km/h; 18,000 mph). The vehicle was controlled by a combination of RCS thrusters and control surfaces, to fly at a 40 degree nose-up attitude, producing high drag, not only to slow it down to landing speed, Sony VAIO VGN-CR490EBL Battery

but also to reduce reentry heating. As the vehicle encountered progressively denser air, it began a gradual transition from spacecraft to aircraft. In a straight line, its 40 degree nose-up attitude would cause the descent angle to flatten-out, or even rise.Sony VAIO VGN-CR490EBN Battery

The vehicle therefore performed a series of four steep S-shaped banking turns, each lasting several minutes, at up to 70 degrees of bank, while still maintaining the 40 degree angle of attack. In this way it dissipated speed sideways rather than upwards. This occurred during the 'hottest' phase of re-entry, when the heat-shield glowed red and the G-forces were at their highest. Sony VAIO VGN-CR490EBP Battery

By the end of the last turn, the transition to aircraft was almost complete. The vehicle leveled its wings, lowered its nose into a shallow dive and began its approach to the landing site.

The orbiter's maximum glide ratio/lift-to-drag ratio varies considerably with speed, ranging from 1:1 at hypersonic speeds, 2:1 at supersonic speeds and reaching 4.5:1 at subsonic speeds during approach and landing.Sony VAIO VGN-CR490EBR Battery

In the lower atmosphere, the orbiter flies much like a conventional glider, except for a much higher descent rate, over 50 m/s (180 km/h; 110 mph)(9800fpm). At approximately Mach 3, two air data probes, located on the left and right sides of the orbiter's forward lower fuselage, are deployed to sense air pressure related to the vehicle's movement in the atmosphere.Sony VAIO VGN-CR490EBT Battery

Final approach and landing phase

When the approach and landing phase began, the orbiter was at a 3,000 m (9,800 ft) altitude, 12 km (7.5 mi) from the runway. The pilots applied aerodynamic braking to help slow down the vehicle. Sony VAIO VGN-CR490EBW Battery

The orbiter's speed was reduced from 682 to 346 km/h (424 to 215 mph), approximately, at touch-down (compared to 260 km/h (160 mph) for a jet airliner). The landing gear was deployed while the Orbiter was flying at 430 km/h (270 mph). To assist the speed brakes, a 12 m (39 ft) drag chute was deployed either after main gear or nose gear touchdown (depending on selected chute deploy mode) at about 343 km/h (213 mph). Sony VAIO VGN-CR50B/W Battery

The chute was jettisoned once the orbiter slowed to 110 km/h (68.4 mph).

Post-landing processing

After landing, the vehicle stayed on the runway for several minutes for the orbiter to cool. Teams at the front and rear of the orbiter tested for presence of hydrogen, hydrazine, monomethylhydrazine, nitrogen tetroxide and ammonia (fuels and by products of the control and the orbiter's three APUs).Sony VAIO VGN-CR51B/W Battery

If hydrogen was detected, an emergency would be declared, the orbiter powered down and teams would evacuate the area. A convoy of 25 specially-designed vehicles and 150 trained engineers and technicians approached the orbiter. Purge and vent lines were attached to remove toxic gasses from fuel lines and the cargo bay about 45–60 minutes after landing. Sony VAIO VGN-CR520E/J Battery

A flight surgeon boarded the orbiter for initial medical checks of the crew before disembarking. Once the crew left the orbiter, responsibility for the vehicle was handed from the Johnson Space Center back to the Kennedy Space Center.Sony VAIO VGN-CR52B/W Battery

If the mission ended at Edwards Air Force Base in California, White Sands Space Harbor in New Mexico, or any of the runways the orbiter might use in an emergency, the orbiter was loaded atop the Shuttle Carrier Aircraft, a modified 747, for transport back to the Kennedy Space Center, landing at the Shuttle Landing Facility. Sony VAIO VGN-CR590EBL Battery

Once at the Shuttle Landing Facility, the orbiter was then towed 2 miles (3.2 km) along a tow-way and access roads normally used by tour busses and KSC employees to the Orbiter Processing Facility where it began a months-long preparation process for the next mission.Sony VAIO VGN-CR590EBN Battery

Landing sites

NASA preferred Space Shuttle landings to be at Kennedy Space Center. If weather conditions made landing there unfavorable, the shuttle could delay its landing until conditions are favorable, touch down at Edwards Air Force Base, California, or use one of the multiple alternate landing sites around the world.Sony VAIO VGN-CR590EBP Battery

A landing at any site other than Kennedy Space Center meant that after touchdown the shuttle must be mated to the Shuttle Carrier Aircraft and returned to Cape Canaveral. Space Shuttle Columbia (STS-3) landed at the White Sands Space Harbor, New Mexico; this was viewed as a last resort as NASA scientists believe that the sand could potentially damage the shuttle's exterior.Sony VAIO VGN-CR590EBR Battery

There were many alternative landing sites that were never used.

Risk contributors

An example of technical risk analysis for a STS mission is SPRA iteration 3.1 top risk contributors for STS-133:

1. Micro-Meteoroid Orbital Debris (MMOD) strikes
2. Space Shuttle Main Engine (SSME)-induced or SSME catastrophic failure Sony VAIO VGN-CR590EBT Battery
3. Ascent debris strikes to TPS leading to LOCV on orbit or entry
4. Crew error during entry
5. RSRM-induced RSRM catastrophic failure (RSRM are the rocket motors of the Solid Rocket Boosters)
6. COPV failure (COPV are tanks inside the orbiter that hold gas at high pressure) Sony VAIO VGN-CR590EBW Battery

An internal NASA risk assessment study (conducted by the Shuttle Program Safety and Mission Assurance Office at Johnson Space Center) released in late 2010 or early 2011 concluded that the agency had seriously underestimated the level of risk involved in operating the shuttle. Sony VAIO VGN-CR60B/L Battery

The report assessed that there was a 1 in 9 chance of a catastrophic disaster during the first nine flights of the shuttle but that safety improvements had later improved the risk ratio to 1 in 100.

Shuttle disasters

On January 28, 1986, Challenger disintegrated 73 seconds after launch due to the failure of the right SRB, killing all seven astronauts on board. Sony VAIO VGN-CR60B/P Battery

The disaster was caused by low-temperature impairment of an O-ring, a mission critical seal used between segments of the SRB casing. The failure of a lower O-ring seal allowed hot combustion gases to escape from between the booster sections and burn through the adjacent external tank, causing it to disintegrate.Sony VAIO VGN-CR60B/R Battery

Repeated warnings from design engineers voicing concerns about the lack of evidence of the O-rings' safety when the temperature was below 53 °F (12 °C) had been ignored by NASA managers.

On February 1, 2003, Columbia disintegrated during re-entry, killing its crew of seven, because of damage to the carbon-carbon leading edge of the wing caused during launch. Sony VAIO VGN-CR61B/L Battery

Ground control engineers had made three separate requests for high-resolution images taken by the Department of Defense that would have provided an understanding of the extent of the damage, while NASA's chief thermal protection system (TPS) engineer requested that astronauts on board Columbia be allowed to leave the vehicle to inspect the damage. Sony VAIO VGN-CR61B/N Battery

NASA managers intervened to stop the Department of Defense's assistance and refused the request for the spacewalk,and thus the feasibility of scenarios for astronaut repair or rescue by Atlantis were not considered by NASA management at the time. Sony VAIO VGN-CR61B/P Battery

Retirement

NASA retired the Space Shuttle in 2011, after 30 years of service. Discovery was the first of NASA's three remaining operational Space Shuttles to be retired. Michael Suffredini of the ISS program said that one additional trip was needed in 2011 to deliver parts to the International Space Station.Sony VAIO VGN-CR61B/R Battery

The final Space Shuttle mission was originally scheduled for late 2010, but the program was later extended to July 2011. Its final mission consisted of just four astronauts—Christopher Ferguson (Commander), Douglas Hurley (Pilot), Sandra Magnus (Mission Specialist 1), and Rex Walheim (Mission Specialist 2);Sony VAIO VGN-CR62B/L Battery

they conducted the 135th and last space shuttle mission on board Atlantis, which launched on July 8, 2011 and landed safely at the Kennedy Space Center on July 21, 2011 at 5:57 AM EDT (09:57 UTC).

Distribution of orbiters and other hardware

NASA announced it would transfer space-worthy orbiters to education institutions or museums at the conclusion of the space shuttle program. Sony VAIO VGN-CR62B/N Battery

Each museum or institution is responsible for covering theUS$28.8 million cost of preparing and transporting each vehicle for display. Twenty museums from across the country submitted proposals for receiving one of the retired orbiters. NASA also made Space Shuttle thermal protection system tiles available to schools and universities for less than US$25 each.Sony VAIO VGN-CR62B/P Battery

About 7,000 tiles were available on a first-come, first-served basis, limited to one per institution.

On April 12, 2011, NASA announced selection of locations for the remaining Shuttle orbiters:

• Atlantis will be on display at the Kennedy Space Center Visitor Complex, near Cape Canaveral, Florida.Sony VAIO VGN-CR62B/R Battery

• Discovery will be delivered to the Udvar-Hazy Center of the Smithsonian Institution's National Air and Space Museum in Chantilly, Virginia, near Washington, D.C.

• Endeavour will be delivered to the California Science Center in Los Angeles, California.

• Enterprise (atmospheric test orbiter), currently on display at the National Air and Space Museum's Udvar-Hazy Center, will be moved to the Intrepid Sea-Air-Space Museum in New York City, New York. Sony VAIO VGN-CR70B/W Battery

Flight and mid-deck training hardware will be taken from the Johnson Space Center and will go to the National Air and Space Museum and theNational Museum of the U.S. Air Force. The full fuselage mockup, which includes the payload bay and aft section but no wings, is to go to the Museum of Flight in Seattle. Sony VAIO VGN-CR71B/W Battery

Mission Simulation and Training Facility's fixed simulator will go to the Adler Planetarium in Chicago, and the motion simulator will go to the Texas A&M Aerospace Engineering Department in College Station, Texas. Other simulators used in shuttle astronaut training will go to the Wings of Dreams Aviation Museum in Starke, Florida and the Virginia Air and Space Center in Hampton, Virginia.Sony VAIO VGN-CR72B/W Battery

In August 2011, the NASA Office of Inspector General (OIG) published a "Review of NASA's Selection of Display Locations for the Space Shuttle Orbiters"; the review had four main findings:

• "NASA's decisions regarding Orbiter placement were the result of an Agency-created process that emphasized above all other considerations locating the Orbiters in places where the most people would have the opportunity to view them";Sony VAIO VGN-CR90HS Battery
• "the Team made several errors during its evaluation process, including one that would have resulted in a numerical 'tie' among the Intrepid, the Kennedy Visitor Complex, and the National Museum of the U.S. Air Force (Air Force Museum) in Dayton, Ohio";Sony VAIO VGN-CR90NS Battery
• there is "no evidence that the Team’s recommendation or the Administrator's decision were tainted by political influence or any other improper consideration";
• "some of the choices NASA made during the selection process – specifically, its decision to manage aspects of the selection as if it were a competitive procurement and to delay announcement of its placement decisions until April 2011 Sony VAIO VGN-CR90S Battery
• (more than 2 years after it first solicited information from interested entities)—may intensify challenges to the Agency and the selectees as they work to complete the process of placing the Orbiters in their new homes."

The NASA OIG had three recommendations, saying NASA should: Sony VAIO VGN-CR92HS Battery

• "expeditiously review recipients' financial, logistical, and curatorial display plans to ensure they are feasible and consistent with the Agency's educational goals and processing and delivery schedules";
• "ensure that recipient payments are closely coordinated with processing schedules, do not impede NASA's ability to efficiently prepare the Orbiters for museum display, and provide sufficient funds in advance of the work to be performed;Sony VAIO VGN-CR92NS Battery
• and""work closely with the recipient organizations to minimize the possibility of delays in the delivery schedule that could increase the Agency's costs or impact other NASA missions and priorities."

In September 2011, the CEO and two board members of Seattle's Museum of Flight met with NASA Administrator Charles Bolden,Sony VAIO VGN-CR92S Battery

pointing out "significant errors in deciding where to put its four retiring space shuttles"; the errors alleged include inaccurate information on Museum of Flight's attendance and international visitor statistics, as well as the readiness of the Intrepid Sea-Air-Space Museum's exhibit site.Sony VAIO VGN-CS118E/Q Battery

Space Shuttle successors and legacy

Until another U.S. launch vehicle is ready, crews will travel to and from the International Space Station aboard Russian Soyuz spacecraft or possibly a future American commercial spacecraft. A planned successor to STS was the "Shuttle II" during the 1980s and 1990s, and later the Constellation program during the 2004–2010 period. Sony VAIO VGN-CS118E/R Battery

CSTS was a proposal to continue to operate STS commercially, after NASA.On September 14, 2011, NASA announced that it had selected the design of a newSpace Launch System that it said would take the agency's astronauts farther into space than ever before and provide the cornerstone for future human space exploration efforts by the U.S.Sony VAIO VGN-CS118E/W Battery

In culture

Space Shuttles have been featured in numerous works of fiction and nonfiction, from movies for kids to documentaries. Early examples include the 1979 James Bond film, Moonraker, where shuttles played a major role well before any were actually launched, Activision videogame Space Shuttle: Sony VAIO VGN-CS11S/P Battery

A Journey into Space (1982) and G. Harry Stine's novel Shuttle Down (1981). In the 1986 film SpaceCamp, Atlantis accidentally launched into space with a group of U.S. Space Campparticipants as its crew. The 1998 film Armageddon portrayed a combined crew of offshore oil rig workers and US military staff who pilot two modified shuttles to avert the destruction of Earth by an asteroid.Sony VAIO VGN-CS11S/Q Battery

Retired American test pilots visited a Russian satellite in the Clint Eastwood adventure film Space Cowboys (2000). This was followed by the 2004 Bollywood movie Swades, where a space shuttle was used to launch a special rainfall monitoring satellite.Sony VAIO VGN-CS11S/W Battery

The movie was filmed at Kennedy Space Center in the year following the Columbia disaster that had taken the life of KC Chawla, the first woman of Indian origin in space. On television, the 1996 drama The Cape portrayed the lives of a group of NASA astronauts as they prepared for and flew shuttle missions. Sony VAIO VGN-CS11Z/R Battery

Odyssey 5 was a short lived sci-fi series that featured the crew of a space shuttle as the last survivors of a disaster that destroyed Earth.

The Space Shuttle has also been the subject of toys and models; for example, a large Lego Space Shuttle model was constructed by visitors at Kennedy Space Center, and smaller models have been sold commercially as a standard "LegoLand" set.Sony VAIO VGN-CS120J/P Battery

A reusable launch system (or reusable launch vehicle, RLV) is a launch system which is capable of launching a launch vehicle into space more than once. This contrasts with expendable launch systems, where each launch vehicle is launched once and then discarded.Sony VAIO VGN-CS120J/Q Battery

No true orbital reusable launch system is currently in use. The closest example is the partially reusable Space Shuttle. The orbiter, which includes the main engines, and the two solid rocket boosters, are reused after several months of refitting work for each launch. The external fuel drop tank is typically discarded, but it is possible for it be re-used in space for various applications.Sony VAIO VGN-CS120J/R Battery

Orbital RLVs are thought to provide the possibility of low cost and highly reliable access to space. However, reusability implies weight penalties such as non-ablative reentry shielding and possibly a stronger structure to survive multiple uses, and given the lack of experience with these vehicles, the actual costs and reliability are yet to be seen.Sony VAIO VGN-CS190JTB Battery

In the early 1950s popular science fiction often depicted space launch vehicles as either single-stage reusable rocketshipswhich could launch and land vertically (SSTO VTVL), or single-stage reusable rocketplanes which could launch and land horizontally (SSTO HTHL).Sony VAIO VGN-CS190JTP Battery

The realities of early engine technology with low specific impulse or insufficient thrust-to-weight ratio to escape ourgravity well, compounded by construction materials without adequate performance (strength, stiffness, heat resistance) and low weight seemingly rendered that original single-stage reusable vehicle vision impossible.Sony VAIO VGN-CS190JTQ Battery

However advances in materials and engine technology have rendered this concept potentially feasible.

Before VTVL SSTO designs came the partially reusable multi-stage NEXUS launcher by Krafft Ehricke. The pioneer in the field of VTVL SSTO, Philip Bono, worked at Douglas. Bono proposed several launch vehicles including:Sony VAIO VGN-CS190JTR Battery

ROOST, ROMBUS, Ithacus,Pegasus and SASSTO. Most of his vehicles combined similar innovations to achieve SSTO capability. Bono proposed:

• Plug nozzle engines to retain high specific impulse at all altitudes.
• Base first reentry which allowed the reuse of the engine as a heat shield, lowering required heat shield mass.Sony VAIO VGN-CS190JTW Battery
• Use of spherical tanks and stubby shape to reduce vehicle structural mass further.
• Use of drop tanks to increase range.
• Use of in-orbit refueling to increase range. Sony VAIO VGN-CS190NAB Battery

Bono also proposed the use of his vehicles for space launch, rapid intercontinental military transport (Ithacus), rapid intercontinental civilian transport (Pegasus), even Moon and Mars missions (Project Selena, Project Deimos).

In Europe, Dietrich Koelle, inspired by Bono's SASSTO design, proposed his own VTVL vehicle named BETA.Sony VAIO VGN-CS190NAC Battery

Before HTHL SSTO designs came Eugen Sänger and his Silbervogel ("Silverbird") suborbital skip bomber. HTHL vehicles which can reach orbital velocity are harder to design than VTVL due to their higher vehicle structural weight. This led to several multi-stage prototypes such as a suborbital X-15. Sony VAIO VGN-CS190NAD Battery
Aerospaceplane being one of the first HTHL SSTO concepts. Proposals have been made to make such a vehicle more viable including:

• Rail boost (e.g. 270 m/s at 3000 m on a mountain allowing 35% less SSTO takeoff mass for a given payload in one NASA study)
• Use of lifting body designs to reduce vehicle structural mass.
• Use of in-flight refueling. Sony VAIO VGN-CS190NBB Battery

Other launch system configuration designs are possible such as horizontal launch with vertical landing (HTVL) and vertical launch with horizontal landing (VTHL). One of the few HTVL vehicles is the 1960s concept spacecraft Hyperion SSTO, designed by by Philip Bono.Sony VAIO VGN-CS190NCA Battery

X-20 Dyna-Soar is an early example of a VTHL design, while the HL-20 and X-34 are examples from the 1990s.As of February 2010, the VTHL X-37 has completed initial development and flown an initial classified orbital mission of over seven months duration.Sony VAIO VGN-CS190NCB Battery

Currently proposed VTHL manned spaceplanes include the Dream Chaser andPrometheus, both circa 2010 concept spaceplanes proposed to NASA under the CCDev program.

The late 1960s saw the start of the Space Shuttle design process. From an initial multitude of ideas a two-stage reusable VTHL design was pushed forward. Sony VAIO VGN-CS190NCC Battery

That eventually ended up as a reusable orbiter with an expendable drop tank and reusable solid rocket boosters to reduce design expenses.

During the 1970s further VTVL and HTHL SSTO designs were proposed for solar power satellite and military applications.Sony VAIO VGN-CS50B/W Battery

There was a VTVL SSTO study by Boeing. HTHL SSTO designs included the Rockwell Star-Raker and the Boeing HTHL SSTO study. However the focus of all space launch funding in the United States on the Shuttle killed off these prospects. The Soviet Union followed suit with Buran. Others preferred expendables for their lower design risk, and lower design cost.Sony VAIO VGN-CS51B/W Battery

Eventually the Shuttle was found to be expensive to maintain, even more expensive than an expendable launch system would have been. The cancellation of a Shuttle-Centaur rocket after the loss of Challenger also caused an hiatus that would make it necessary for the United States military to scramble back towards expendables to launch their payloads. Sony VAIO VGN-CS52JB/W Battery

Many commercial satellite customers had switched to expendables even before that, due to unresponsiveness to customer concerns by the Shuttle launch system.

In 1986 President Ronald Reagan called for an airbreathing scramjet plane to be built by the year 2000, called NASP/X-30 that would be capable of SSTO. Sony VAIO VGN-CS60B/P Battery

Based on the research project copper canyon the project failed due to severe technical issues and was cancelled in 1993.

This research may have inspired the British HOTOL program, which rather than airbreathing to high hypersonic speeds as with NASP, proposed to use a precooler up to Mach 5.5. Sony VAIO VGN-CS60B/Q Battery

The program's funding was canceled by the British government when the research identified some technical risks as well as indicating that that particular vehicle architecture would only be able to deliver a relatively small payload size to orbit.

When the Soviet Union imploded in the early nineties, the cost of Buran became untenable. Russia has only used pure expendables for space launch since.Sony VAIO VGN-CS60B/R Battery

The 1990s saw interest in developing new reusable vehicles. The military Strategic Defense Initiative ("Star Wars") program "Brilliant Pebbles" required low cost, rapid turnaround space launch. From this requirement came the McDonnell Douglas Delta Clipper VTVL SSTO proposal. Sony VAIO VGN-CS61B/P Battery

The DC-X prototype for Delta Clipper demonstrated rapid turnaround time and that automatic computer control of such a vehicle was possible. It also demonstrated it was possible to make a reusable space launch vehicle which did not require a large standing army to maintain like the Shuttle.Sony VAIO VGN-CS61B/Q Battery

In mid-1990, further British research and major reengineering to avoid deficiencies of the HOTOL design led to the far more promising Skylon design, with much greater payload.

From the commercial side, large satellite constellations such as Iridium satellite constellation were proposed which also had low cost space access demands. Sony VAIO VGN-CS61B/R Battery

This fueled a private launch industry, including partially reusable vehicle players, such as Kistler, and reusable vehicle players such as Rotary Rocket.

The end of that decade saw the implosion of the satellite constellation market with the bankruptcy of Iridium. In turn the nascent private launch industry collapsed. Sony VAIO VGN-CS62JB/P Battery

The fall of the Soviet Union eventually had political ripples which led to a scaling down of ballistic missile defense, including the demise of the "Brilliant Pebbles" program. The military decided to replace their aging expendable launcher workhorses, evolved from ballistic missile technology, with the EELV program. Sony VAIO VGN-CS62JB/Q Battery

NASA proposed riskier reusable concepts to replace Shuttle, to be demonstrated under the X-33 and X-34 programs.

The 21st century saw rising costs and teething problems lead to the cancellation of both X-33 and X-34. Then the Space Shuttle Columbia disaster and another grounding of the fleet. Sony VAIO VGN-CS62JB/R Battery

The Shuttle design was now over 20 years old and in need of replacement. Meanwhile the military EELV program churned out a new generation of better expendables. The commercial satellite market is depressed due to a glut of cheap expendable rockets and there is a dearth of satellite payloads.Sony VAIO VGN-CS71B/W Battery

Against this dire backdrop came the Ansari X Prize contest, inspired by the aviation contests made in the early 20th century. Many private companies competed for the Ansari X Prize, the winner being Scaled Composites with their reusable HTHL SpaceShipOne.Sony VAIO VGN-CS72JB/W Battery

It won the ten million dollars, by reaching 100 kilometers in altitude twice in a two week period with the equivalent of three people on board, with no more than ten percent of the non-fuel weight of the spacecraft replaced between flights. While SpaceShipOne is suborbital like the X-15, Sony VAIO VGN-CS90HS Battery

some hope the private sector can eventually develop reusable orbital vehicles given enough incentive. SpaceXis a recent player in the private launch market which has partially reusable vehicles.

Single stage

There are two approaches to Single stage to orbit or SSTO. The rocket equation says that an SSTO vehicle needs a high mass ratio.Sony VAIO VGN-CS90NS Battery

Mass ratio is defined as the mass of the fully fueled vehicle divided by the mass of the vehicle when empty (zero fuel weight, ZFW).

One way to increase the mass ratio is to reduce the mass of the empty vehicle by using very lightweight structures and high efficiency engines. Sony VAIO VGN-CS90S Battery

This tends to push up maintenance costs as component reliability can be impaired, and makes reuse more expensive to achieve. The margins are so small with this approach that there is uncertainty whether such a vehicle would be able to carry any payload into orbit. Also, lightweight implies small vehicles, which in turn implies small payloads, increasing the cost per kilogram of the payload.Sony VAIO VGN-CS91HS Battery

Two or more stages to orbit

Two stage to orbit requires designing and building two independent vehicles and dealing with the interactions between them at launch. Usually the second stage in launch vehicle is 5-10 times smaller than the first stage, although in biamese and triameseapproaches each vehicle is the same size.Sony VAIO VGN-CS91NS Battery

In addition, the first stage needs to be returned to the launch site for it to be reused. This is usually proposed to be done by flying a compromise trajectory that keeps the first stage above or close to the launch site at all times, or by using small airbreathing engines to fly the vehicle back, Sony VAIO VGN-CS91S Battery

or by recovering the first stage downrange and returning it some other way (often landing in the sea, and returning it by ship.) Most techniques involve some performance penalty; these can require the first stage to be several times larger for the same payload, although for recovery from downrange these penalties may be small.Sony VAIO VGN-CS92DS Battery

The second stage is normally returned after flying one or more orbits and reentering.

Horizontal landing

In this case the vehicle requires wings and undercarriage (unless landing at sea). This typically requires about 9-12% of the landing vehicle to be wings; which in turn implies that the takeoff weight is higher and/or the payload smaller.Sony VAIO VGN-CS92JS Battery

Concepts such as lifting bodies attempt to deal with the somewhat conflicting issues of reentry, hypersonic and subsonic flight; as does the delta wing shape of the Space Shuttle.

Vertical landing

Parachutes could be used to land vertically, either at sea, or with the use of small landing rockets, on land (as with Soyuz).Sony VAIO VGN-CS92XS Battery

Alternatively rockets could be used to softland the vehicle on the ground from the subsonic speeds reached at low altitude (seeDC-X). This typically requires about 10% of the landing weight of the vehicle to be propellant.

A slightly different approach to vertical landing is to use an autogyro or helicopter rotor. This requires perhaps 2-3% of the landing weight for the rotor.Sony VAIO VGN-FW11E Battery

Horizontal takeoff

The vehicle needs wings to take off. For reaching orbit, a 'wet wing' would often need to be used where the wing contains propellant. Around 9-12% of the vehicle takeoff weight is perhaps tied up in the wings.

Vertical takeoff

This is the traditional takeoff regime for pure rocket vehicles. Rockets are good for this regime, since they have a very high thrust/weight ratio (~100).Sony VAIO VGN-FW11L Battery

Airbreathing

Airbreathing approaches use the air for propulsion during ascent. The most commonly proposed approach is the scramjet, butturborocket, Liquid Air Cycle Engine (LACE) and precooled jet engines are also proposed to be used.

In all cases the highest speed that airbreathing can reach is far short of orbital speed (about Mach 15 for Scramjets and Mach 5-6 for the other engine designs) and rockets would be used for the remaining 10-20 Mach for orbit.Sony VAIO VGN-FW11M Battery

The thermal situation for airbreathers (particularly scramjets) can be awkward; normal rockets fly steep initial trajectories to avoid drag, whereas scramjets would deliberately fly through relatively thick atmosphere at high speed generating enormous heating of the airframe. The thermal situation for the other airbreathing approaches is much more benign, although is not without its challenges.Sony VAIO VGN-FW11S Battery

Hydrogen fuel

Hydrogen is often proposed since it has the highest exhaust velocity. However tankage and pump weights are high due to insulation and low propellant density; and this wipes out much of the advantage.

Still, the 'wet mass' of a hydrogen fuelled stage is lighter than an equivalent dense stage with the same payload and this can permit usage of wings, and is good for second stages.Sony VAIO VGN-FW11ZU Battery

Dense fuel

Dense fuel is sometimes proposed since, although it implies a heavier vehicle, the specific tankage and pump mass is much improved over hydrogen. Dense fuel is usually suggested for vertical takeoff vehicles, and is compatible with horizontal landing vehicles, since the vehicle is lighter than an equivalent hydrogen vehicle when empty of propellant. Sony VAIO VGN-FW139E/H Battery

Non-cryogenic dense fuels also permit the storage of fuel in wing structures. Projects have been underway to densify existing fuel types through various techniques. These include slush technologies for cryogenics like hydrogen and propane. Another densifying method has been studied that would also increase the specific impulse of fuels. Sony VAIO VGN-FW140AE Battery

Adding finely powdered carbon, aluminum, titanium, and boron to hydrogen and kerosene have been studied. These additives increase the specific impulse (Isp) but also the density of the fuel. For instance, the French ONERA missile program tested boron with kerosene in gelled slurries, as well as embedded in paraffin, and demonstrated increases in volumetric specific impulse of between 20-100%.Sony VAIO VGN-FW140D Battery

Tripropellant

Dense fuel is optimal early on in a flight, since the thrust to weight of the engines is better due to higher density; this means the vehicle accelerates more quickly and reaches orbit sooner, reducing gravity losses.

However, for reaching orbital speed, hydrogen is a better fuel, since the high exhaust velocity and hence lower propellant mass reduces the take off weight.Sony VAIO VGN-FW140E Battery

Therefore tripropellant vehicles start off burning with dense fuel and transition to hydrogen. (In a sense the Space Shuttle does this with its combination of solid rockets and main engines, but tripropellant vehicles usually carry their engines to orbit. Sony VAIO VGN-FW140E/H Battery

Propellant costs

As with all current launch vehicles propellant costs for a rocket are much lower than the costs of the hardware. However, for reusable vehicles if the vehicles are successful, then the hardware is reused many times and this would bring the costs of the hardware down.Sony VAIO VGN-FW140E/W Battery

In addition, reusable vehicles are frequently heavier and hence less propellant efficient, so the propellant costs could start to multiply up to the point where they become significant.

Launch assistance

Since rocket delta-v has a non linear relationship to mass fraction due to the rocket equation, any small reduction in delta-v gives a relatively large reduction in the required mass fraction; and starting a mission at higher altitude also helps.

Many systems have proposed the use of aircraft to gain some initial velocity and altitude; either by towing, carrying or even simply refueling a vehicle at altitude.Sony VAIO VGN-FW140FE Battery

Various other launch assists have been proposed, such as ground based sleds, or maglev systems, high altitude (80 km) maglev systems such as launch loops, to more exotic systems such as tether propulsion systems to catch the vehicle at high altitude, or even Space Elevators.Sony VAIO VGN-FW140N Battery

Reentry heat shields

Robert Zubrin has said that as a rough rule of thumb, 15% of the landed weight of a vehicle needs to be aerobraking reentry shielding.

Reentry heat shields on these vehicles are often proposed to be some sort of ceramic and/or carbon-carbon heat shields, or occasionally metallic heat shields (possibly using water cooling or some sort of relatively exotic rare earth metal.)Sony VAIO VGN-FW140N/W Battery

Some shields would be single use ablatives and would be discarded after reentry.

A newer Thermal Protection System (TPS) technology was first developed for use in steering fins on ICBM MIRVs. Given the need for such warheads to reenter the atmosphere swiftly and retain hypersonic velocities to sea level,Sony VAIO VGN-FW145E Battery

researchers developed what are known as SHARP materials, typically hafnium diboride and zirconium diboride, whose thermal tolerance exceeds 3600 C. SHARP equipped vehicles can fly at Mach 11 at 30 km altitude and Mach 7 at sea level. The sharp-edged geometries permitted with these materials also eliminates plasma shock wave interference in radio communications during reentry.Sony VAIO VGN-FW145E/W Battery

SHARP materials are very robust and would not require constant maintenance, as is the case with technologies like silica tiles, used on the Space Shuttle, which account for over half of that vehicles maintenance costs and turnaround time. The maintenance savings alone are thus a major factor in favor of using these materials for a reusable launch vehicle, whose raison d'etre is high flight rates for economical launch costs.Sony VAIO VGN-FW160AE Battery

Weight penalty

The weight of a reusable vehicle is almost invariably higher than an expendable that was made with the same materials, for a given payload.

R&D

The R&D costs of reusable vehicle are expected to be higher, because making a vehicle reusable implies making it robust enough to survive more than one use, which adds to the testing required. Sony VAIO VGN-FW160D Battery

Increasing robustness is most easily done by adding weight; but this reduces performance and puts further pressure on the R&D to recoup this in some other way.

These extra costs must be recouped; and this pushes up the average cost of the vehicle.Sony VAIO VGN-FW160E Battery

Maintenance

Reusable launch systems require maintenance, which is often substantial. The Space Shuttle system requires extensive refurbishing between flights, primarily dealing with the silica tile TPS and the high performance LH2/LOX burning main engines. Sony VAIO VGN-FW160E/H Battery

Both systems require a significant amount of detailed inspection, rebuilding and parts replacement between flights, and account for over 75% of the maintenance costs of the Shuttle system. These costs, far in excess of what had been anticipated when the system was constructed, have cut the maximum flight rate of Shuttle to 1/4 of that planned. Sony VAIO VGN-FW160F/E Battery

This has also quadrupled the cost per pound of payload to orbit, making Shuttle economically infeasible in today's launch market for any but the largest payloads, for which there is no competition.

For any RLV technology to be successful, it must learn from the failings of Shuttle and overcome those failings with new technologies in the TPS and propulsion areas.Sony VAIO VGN-FW170J/H Battery

Manpower & Logistics

The Space Shuttle program requires a standing army of over 9,000 employees to maintain, refurbish, and relaunch the shuttle fleet, irrespective of flight rates. That manpower budget must be divided by the total number of flights per year. The fewer flights means the cost per flight goes up significantly. Sony VAIO VGN-FW180AE Battery

Streamlining the manpower requirements of any launch system is an essential part of making an RLV economical. Projects that have attempted to develop this ethic include the DC-X Delta Clipper project, as well as the current SpaceX Falcon 1 and Falcon 9 programs.Sony VAIO VGN-FW180D Battery

One issue mitigating against this drive for labor savings is government regulation. Given that NASA and USAF (as well as government programs in other countries) are the primary customers and sources of development capital,Sony VAIO VGN-FW180E Battery

government regulatory requirements for oversight, parwork, quality, safety, and other documentation tend to inflate the operational costs of any such system.Sony VAIO VGN-FW180E/H Battery,Sony VAIO VGN-FW180FU Battery,Sony VAIO VGN-FW190EBH Battery