Space Shuttle program
This article is about the NASA Space Shuttle. For information on the Soviet space shuttle, see the article Shuttle Buran.NASA's
Space Shuttle, officially called
Space Transportation System (
STS), is the
United States government's current
manned launch vehicle. The winged shuttle orbiter is launched vertically, usually carrying five to seven
astronauts (although eight have been carried) and up to 50,000
lb (22,700
kg) of payload into
low earth orbit. When its mission is complete, it fires its maneuvering thrusters to drop out of orbit and
re-enters the
earth's atmosphere. During the descent and landing, the shuttle orbiter acts as a glider and makes a completely unpowered landing.
The Shuttle is the first orbital
spacecraft designed for partial
reusability. It is also so far the only winged manned spacecraft to achieve orbit and land. It carries large payloads to various orbits, provides crew rotation for the
International Space Station (ISS), and performs servicing missions. The orbiter can also recover
satellites and other payloads from orbit and return them to
Earth, but this capacity has not been used often. However, it has been used to return large payloads from the ISS to earth, as the Russian
Soyuz spacecraft has limited capacity for return payloads. Each Shuttle was designed for a projected lifespan of 100 launches or 10 years' operational life.
The program started in the late 1960s and has dominated NASA's manned operations since the mid-1970s. According to the
Vision for Space Exploration, use of the Space Shuttle will be focused on completing assembly of the ISS in 2010 (more specifically, the construction completion of the ISS), after which it will be replaced by the
Crew Exploration Vehicle (CEV).
Even before the
Apollo moon landing in 1969, in October 1968 NASA began early studies of space shuttle designs. The early studies were denoted "Phase A", and in June 1970, "Phase B", which were more detailed and specific.
In 1969 President
Richard Nixon formed the Space Task Group, chaired by vice president
Spiro T. Agnew. They evaluated the shuttle studies to date, and
recommended a national space strategy including building a space shuttle.
[Heppenheimer, T.A. The Space Shuttle Decision: NASA's Search for a Reuseble Space Vehicle. Washington, DC: National Aeronautics and Space Administration, 1999.] During early shuttle development there was great debate about the optimal shuttle design that best balanced capability, development cost and operating cost. Ultimately the current design was chosen, using a reusable winged orbiter,
solid rocket boosters, and
expendable external tank.
The Shuttle program was formally launched on
January 5,
1972, when President Nixon announced that NASA would proceed with the development of a reusable Space Shuttle system.
The final design was less costly to build and less technically ambitious than earlier fully reusable designs.
The prime contractor for the program was
North American Aviation (later
Rockwell International), the same company responsible for the
Apollo Command/Service Module. The contractor for the
Space Shuttle Solid Rocket Boosters was
Morton Thiokol (now part of
Alliant Techsystems), for the
external tank,
Martin Marietta (now
Lockheed Martin), and for the
Space shuttle main engines,
Rocketdyne.
The first complete orbiter was originally named
Constitution, but a massive write-in campaign from fans of the
Star Trek television series convinced the White House to change the name to
Enterprise.
[Brooks, Dawn The Names of the Space Shuttle Orbiters. Washington, DC: National Aeronautics and Space Administration. Accessed July 26, 2006.] Amid great fanfare, the
Enterprise was rolled out on
September 17,
1976, and later conducted a successful series of glide-approach and landing tests that were the first real validation of the design.
The first fully functional Shuttle Orbiter was the
Columbia, built in
Palmdale, California. It was delivered to
Kennedy Space Center on
March 25,
1979, and was first launched on
April 12,
1981—the 20th anniversary of
Yuri Gagarin's space flight—with a crew of two.
Challenger was delivered to KSC in July 1982,
Discovery in November 1983, and
Atlantis in April 1985.
Challenger was destroyed when it
disintegrated during ascent due to O-Ring failure on the right SRB on
January 28,
1986, with the loss of all seven astronauts on board.
Endeavour was built to replace
Challenger (using spare parts originally intended for the other Orbiters) and delivered in May 1991; it was first launched a year later. Seventeen years after
Challenger,
Columbia was lost, with all seven crew members, during reentry on
February 1,
2003, and has not been replaced. Out of five functional shuttle orbiters only three remain for use.
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Atlantis sits atop the Mobile Launcher Platform (MLP). It consists of Orbiter (on top), External Tank (at center), and Solid Rocket Boosters (to the right and left of External Tank). Two Tail Service Masts (TSMs) to either side of the Orbiter's tail provide umbilical connections for propellant loading and electrical power. |
The Shuttle is a
partially reusable launch system composed of three main assemblies: the reusable Orbiter Vehicle (OV), the expendable
External Tank (ET), and the two reusable
Solid Rocket Boosters (SRBs). The tank and boosters are jettisoned during ascent; only the orbiter goes into orbit. The vehicle is launched vertically like a conventional rocket, and the orbiter glides to a horizontal landing, after which it is refurbished for reuse.
Orbiter Vehicle
The Orbiter resembles an 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 45° angle. 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, control the Orbiter during descent and landing.
The Orbiter's crew cabin consists of three levels: the flight deck, the mid-deck, and the utility area. The upper-most is the flight deck which seats the commander and pilot, with two mission specialists behind them. The mid-deck, which is below the flight deck, has three more seats for the rest of the crew members. The galley, toilet, sleep locations, storage lockers, and the side hatch for entering/exiting the vehicle are also located on the mid-deck, as is the
airlock hatch. The airlock has another hatch into the payload bay. It allows two astronauts, wearing their
Extravehicular Mobility Unit (EMU) space suits, to depressurize before a
space walk.
The Orbiter has a large 60 by 15 ft (18 m by 4.6 m) payload bay, filling most of the fuselage. The payload bay doors have
heat radiators mounted on their inner surfaces, and so are kept open for thermal control while the Shuttle is in orbit. Thermal control is also maintained by adjusting the orientation of the Shuttle relative to Earth and Sun. Inside the payload bay is the
Remote Manipulator System, also known as the
Canadarm, a robot arm used to retrieve and deploy payloads. Until the loss of Columbia, the Canadarm had been used only on those missions where it was needed. Since the arm is a crucial part of the
Thermal Protection Inspection procedures now required for Shuttle flights, it will probably be included on all future flights.
Three
Space Shuttle Main Engines (SSMEs) are mounted on the Orbiter's aft fuselage in a triangular pattern. The three engines 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 and steer the Shuttle as well as push.
The
Orbital Maneuvering System (OMS) provides orbital maneuvers, including insertion, circularization, transfer, rendezvous,
abort to orbit, and abort once around.
The
Reaction Control System (RCS) provides
attitude control and translation along the pitch, roll, and yaw axes during the flight phases of orbit insertion, orbit, and re-entry.
The
Thermal Protection System (TPS) covers the outside of the Orbiter, protecting it from the cold soak of -121 °C (-250 °F) in space to the 1649 °C (3000 °F) heat of re-entry.
The orbiter structure is made primarily from
aluminium alloy, although the engine thrust structure is made from
titanium (alloy?).
External Tank
The
External Tank (ET) provides approximately 535,000 gallons (2.025 million liters) of
liquid hydrogen and
liquid oxygen propellant to the
SSMEs. It is discarded 8.5 minutes after launch at an altitude of 60 nautical miles (111 km), which then burns up on re-entry. The ET is constructed mostly of 1/8 inch thick aluminium-
lithium alloy.
The external tanks of the first two missions were painted white, which added an extra 600 pounds (273 kg) of weight to each ET. Subsequent missions have had unpainted tanks showing the natural orange-brown color of the spray-on foam insulation. The lighter, unpainted tanks have increased the
payload capacity by almost the entire weight savings of 600 pounds.
[National Aeronautics and Space Administration "NASA Takes Delivery of 100th Space Shuttle External Tank." Press Release 99-193. 16 Aug 1999.]Solid Rocket Boosters
Two
Solid Rocket Boosters (SRBs) provide about 83% of the vehicle's thrust at liftoff and during the first stage ascent. They are jettisoned two minutes after launch at a height of about 150,000 feet (45.7 km), then deploy parachutes and land in the ocean to be recovered. The SRB cases are made of steel about 1/2 inch (1.27 cm) thick.
Flight systems
Early Shuttle missions took along the
GRiD Compass, arguably one of the first
laptop computers. The Compass sold poorly, because it cost at least $8000, but offered unmatched performance for its weight and size. NASA was one of its main customers.
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 connect the pilot's control stick to the control surfaces or
reaction control system thrusters.
A primary concern with digital fly-by-wire systems is reliability. Much research went into the shuttle computer system. The shuttle uses five identical redundant IBM 32-bit general purpose computers (GPCs), model
AP-101, constituting a type of
embedded system. Four computers run specialized software called the Primary Avionics Software System (PASS). A fifth backup computer runs separate software called the Backup Flight System (BFS). Collectively they are called the shuttle Data Processing System (DPS).
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Atlantis deploys landing gear before landing on a selected runway just like a common aircraft. |
The design goal of the shuttle DPS is fail operational/fail safe reliability. After a single failure the shuttle can continue the mission. After two failures it can land safely.
The four general-purpose computers operate essentially in lockstep, checking each other. If one computer fails, the three functioning computers "vote" it out of the system. This isolates it from vehicle control. If a second computer of the three remaining fails, the two functioning computers vote it out. In the rare case of two out of four computers simultaneously failing (a two-two split), one group is picked at random.
The Backup Flight System (BFS) is separately developed software running on the fifth computer, used only if the entire four-computer primary system fails. The BFS was created because although the four primary computers are hardware redundant, they all run the same software, so a generic software problem could crash all of them. This should never happen, as
embedded system avionic software is developed under totally different conditions from commercial software. For example, the number of code lines is tiny compared to a commercial operating system, changes are only made infrequently and with extensive testing, and many programming and test personnel work on the small amount of computer code. However in theory it can fail, and the BFS exists for that contingency.
The software for the shuttle computers is 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 have no hard disk drive, but load software from tape cartridges.
In 1990 the original computers were replaced with an upgraded model AP-101S, which has 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.
Upgrades
Internally the Shuttle remains largely similar to the original design, with the exception of the improved avionics computers. In addition to the computer upgrades, the original
vector graphics monochrome cockpit displays were replaced with modern full-color, flat-panel display screens, similar to contemporary airliners like the
Airbus A320. This is called a "
glass cockpit". In the
Apollo-Soyuz Test Project tradition, programmable calculators are carried as well (originally the
HP-41C). With the coming of the ISS, the Orbiter's internal airlocks have been 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 have had several improvements to enhance reliability and power. This explains phrases such as "Main engines throttling up to 104%." This does not mean the engines are being run over a safe limit. The 100% figure is the original specified power level. During the lengthy development program,
Rocketdyne determined the engine was capable of safe reliable operation at 104% of the originally specified thrust. They could have rescaled the output number, saying in essence 104% is now 100%. However this would have required revising much previous documentation and software, so the 104% number was retained. SSME upgrades are denoted as "block numbers", such as block I, block II, and block IIA. The upgrades have 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 is 104%, with 106% and 109% available for
abort emergencies. For the two first 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 results in an increase in payload capability to orbit. 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". This version of the tank is made of the 2195 aluminium-lithium alloy. It weighs 7,500 lb (3.4 t) less than the last run of lightweight tanks. As the Shuttle cannot fly unmanned, each of these improvements has been "tested" on operational flights.
The SRBs (Solid Rocket Boosters) have undergone improvements as well. Notable is the adding of a third
O-ring seal to the joints between the segments, which occurred after the
Challenger accident.
Several other SRB improvements were planned in order 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 which was to have entered production in the early to mid-1990s to support the Space Station, but was later cancelled to save money after the expenditure of $2.2 billion. The loss of the ASRB program forced the development of the Super LightWeight external Tank (SLWT), which provides 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 cancelled.
STS-70 was delayed in 1995 when woodpeckers holed the foam insulation of Discovery's external tank. Since then, NASA has installed commercial plastic owl decoys and inflatable owl balloons which must be removed prior to launch. [
1]
A cargo-only, unmanned variant of the Shuttle has been variously proposed and rejected since the 1980s. It is called the
Shuttle-C and would trade re-usability for cargo capability with large potential savings from reusing technology developed for the Space Shuttle.
On the first four Shuttle missions, astronauts wore full-pressure
Launch Entry Suit (LES) including a helmet during ascent and descent. From the fifth flight,
STS-5, until the loss of Challenger only helmets were worn without a suit. The LES with a helmet was reinstated when Shuttle flights resumed in 1988. The LES ended its service life in late 1995, replaced by the
Advanced Crew Escape Suit (ACES).
Technical data
Orbiter Specifications (for Endeavour, OV-105)
* Length: 122.17 ft (37.24 m)
* Wingspan: 78.06 ft (23.79 m)
* Height: 58.58 ft (17.25 m)
* Empty Weight: 151,205 lb (68,586.6 kg)
* Gross Liftoff Weight: 240,000 lb (109,000 kg)
* Maximum Landing Weight: 230,000 lb (104,000 kg)
* Main Engines: Three Rocketdyne Block 2 A SSMEs, each with a sea level thrust of 393,800 lbf (178,624 kgf / 1.75MN)
* Maximum Payload: 55,250 lb (25,061.4 kg)
* Payload Bay dimensions: 15 ft by 60 ft (4.6 m by 18.3 m)
* Operational Altitude: 100 to 520 nmi (185 to 1,000 km)
* Speed: 25,404 ft/s (7,743 m/s, 27,875 km/h, 17,321 mi/h)
* Crossrange: 1,085 nautical miles (2,009.4 km)
* Crew: Seven (Commander, Pilot, two Mission Specialists, and three Payload Specialists), two for minimum.
External Tank Specifications (for SLWT)
* Length: 153.8 ft (46.9 m)
* Diameter: 27.6 ft (8.4 m)
* Propellant Volume: 535,000 gallon (2,030,000 L)
* Empty Weight: 58,500 lb (26,559 kg)
* Gross Liftoff Weight: 1.667 million lb (757,000 kg)
Solid Rocket Booster Specifications* Length: 149.6 ft (45.6 m)
* Diameter: 12.17 ft (3.71 m)
* Empty Weight: 139,490 lb (63,272.7 kg)
* Gross Liftoff Weight: 1.3 million lb (590,000 kg)
* Thrust (sea level, liftoff): 2.8 million lbf (1,270,058 kgf / 12.46MN)
System Stack Specifications* Height: 184.2 ft (56.14 m)
* Gross Liftoff Weight: 4.5 million lb (2.04 million kg)
* Total Liftoff Thrust: 6.781 million lbf (3.076 million kgf / 30.18MN)
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Space Shuttle Challenger's rollout from Orbiter Processing Facility (OPF) to the Vehicle Assembly Building (VAB) to be stacked with External tank and SRB's for launch. Photo courtesy of NASA |
The shuttle will not be launched under conditions where it could be 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. Like most jet airliners, the shuttle is mainly constructed of conductive aluminium, which would normally protect the internal systems. However, upon takeoff the shuttle sends out a long exhaust plume as it ascends, and this plume can trigger lightning by providing a current path to ground. While the shuttle might safely endure a lightning strike, a similar strike caused problems on
Apollo 12, so for safety
NASA chooses not to launch the shuttle if lightning is possible.
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Water is released onto the mobile launcher platform on Launch Pad 39A at the start of a rare sound suppression system test in 2004. During launch, 300,000 gallons are poured onto the pad in only 20 seconds. |
At T minus 16 seconds, the massive sound suppression system (SPS) begins to drench the
Mobile Launcher Platform (MLP) and SRB trenches with 300,000 U.S. gallons (1,135,623 L) of water to protect the Orbiter from damage by
acoustical energy and rocket exhaust reflected from the flame trench and MLP during liftoff.
[National Aeronautics and Space Administration. "Sound Suppression Water System" Revised 2000-08-28. Accessed 2006-07-09. ]At T-minus ten seconds, hydrogen ignitors are activated beneath each engine bell to quell the stagnant gas inside the cones before ignition. Failure to burn excess gasses before ignition can trip the onboard sensors and create the possibility of overpressure and explosion during the firing phase.
The three
Space Shuttle Main Engines (SSMEs) start at T minus 6.6 seconds.
[National Aeronautics and Space Administration. "NASA - Countdown 101" Accessed 2006-07-10. ] All three SSMEs must reach the required 100% thrust within three seconds. If the onboard computers verify normal thrust buildup, at T minus 0 the
SRBs are ignited. At that point the vehicle is committed to takeoff, as the SRBs cannot be turned off once ignited. After the SRB's reach a stable thrust pyrotechnic fasteners, large nuts that split in half, are detonated to release the craft. There are extensive emergency procedures (
abort modes) to handle various failure scenarios during ascent. Many of these concern SSME failures, since that is the most complex and highly stressed component. After the
Challenger disaster, there were extensive upgrades to the abort modes.
When watching a launch, look for the "nod" ("twang" in "NASAese"). After the main engines start, but while the solid rocket boosters are still clamped to the pad, the offset thrust from the Shuttle's three main engines causes the entire launch stack (boosters, tank and shuttle) to flex forwards about 2m at cockpit level. As the boosters flex back into their original shape, the launch stack springs slowly back upright. This takes approximately 6 seconds. At the point when it is perfectly vertical, the boosters ignite and the launch commences.
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Shuttle launch of Atlantis at sunset in 2001. The sun is behind the camera, and the plume's shadow intersects the moon across the sky. |
Shortly after clearing the tower the Shuttle begins a roll and pitch program so that the vehicle is below the external tank and SRBs. The vehicle climbs in a progressively flattening arc, accelerating as the weight of the SRBs and main tank decrease. To achieve low orbit requires much more horizontal than vertical acceleration. This is not visually obvious since the vehicle rises vertically and is out of sight for most of the horizontal acceleration. Orbital velocity at the 380 km (236 miles) altitude of the
International Space Station is 7.68 km per second (27,648 km/h, 17,180 mph), roughly equivalent to Mach 23. For missions towards the International Space Station, the shuttle must reach an azimuth of 51.6 degrees inclination to rendezvous with the station.
Around a point called "
Max Q", where the aerodynamic forces are at their maximum, the main engines are temporarily throttled back to avoid
overspeeding and hence overstressing the Shuttle (particularly vulnerable parts such as the wings). At this point, a phenomenon known as the "
Prandtl-Glauert Singularity" occurs, where condensation clouds form during the vehicle's transition to supersonic speed.
126 seconds after launch,
explosive bolts release the SRBs and small separation rockets push them laterally away from the vehicle. The SRBs parachute back to the ocean to be reused. The Shuttle then begins accelerating to orbit on the
Space Shuttle Main Engines. The vehicle at that point in the flight has a thrust to weight ratio of less than one — the main engines actually have insufficient thrust to exceed the force of gravity, and the vertical speed given to it by the SRBs temporarily decreases. However, as the burn continues, the weight of the propellant reduces and the ever-lighter vehicle produces more and more acceleration until the thrust to weight ratio exceeds 1 again and the vehicle can hold itself up.
The vehicle continues to climb and takes on a somewhat nose-up angle to the horizon — it uses the main engines to gain and then maintains altitude whilst it accelerates horizontally towards orbit.
Finally, in the last tens of seconds of the main engine burn, the mass of the vehicle is low enough that the engines must be throttled back to limit vehicle acceleration to 3 g, largely for astronaut comfort.
Before complete depletion of propellant (running dry would destroy the engines) the main engines are shut down and the external tank is released by firing explosive bolts. The tank then falls, largely to burn up in the atmosphere, with some fragments falling into the Indian Ocean.
To keep the shuttle from following the external tank back into the atmosphere, the
OMS engines are fired to raise the perigee out of the atmosphere. On some missions (e.g., STS-107 and missions to the ISS), the OMS engines are also used while the main engines are still firing.
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The outside of the Shuttle heats to over 1,500 °C during reentry. |
The vehicle begins reentry by firing the
OMS engines in the opposite direction to orbital motion for about three minutes. The resulting deceleration of the Shuttle lowers its orbit
perigee down into the atmosphere. This OMS firing is done roughly halfway around the globe from the landing site. The entire reentry, except for lowering the landing gear and deploying the air data probes, is then under computer control. However the reentry can be and has (once) been flown manually. The final landing can be done on autopilot, but is usually hand flown.
The vehicle starts significantly entering the atmosphere at about 400,000 ft (120 km) at around
Mach 25 (8.2 km/s). The vehicle is controlled by a combination of RCS thrusters and control surfaces, to fly at a 40 degrees nose-up attitude producing high drag, not only to slow it down to landing speed, but also to reduce reentry heating. In addition, the vehicle needs to bleed off extra speed before reaching the landing site. This is achieved by performing s-curves at up to a 70 degree roll angle.
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Endeavour deploys drag chute after touch-down. |
In the lower atmosphere the Orbiter flies much like a conventional glider, except for a much higher descent rate, over 10,000 feet (3 km) per minute. It glides with a
glide angle of 4:1. 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 vehicle's movement in the atmosphere.
When the approach and landing phase begins, the Orbiter is at 10,000 ft (3048 m) altitude, 7.5 miles (12.1 km) to the runway. The pilots apply aerodynamic braking to help slow down the vehicle. The Orbiter's speed is reduced from 424 mph (682 km/h) to approximately 215 mph (346 km/h), (compared to 160 mph for a jet airliner), at touch-down. The landing gear is deployed while the Orbiter is flying at 267 mph (430 km/h). To assist the speed brakes, a 40 ft (12.2 m) drag chute is deployed once the nose gear touches down at about 213 mph (343 km/h). It is jettisoned as the Orbiter slows through 69 mph (111 km/h).
After landing, the vehicle stands on the runway for several minutes to permit the fumes from poisonous
hydrazine, used as propellant for
attitude control, to dissipate.
Individual Orbiters are both
named, in a manner similar to ships, and
numbered, using the NASA
Orbiter Vehicle Designation system. While all Orbiters are externally very similar, they have minor internal differences; new equipment is fitted on a rotating basis as they are maintained, and the newer Orbiters tend to be structurally lighter.
In addition to the test articles and Orbiters produced for use in the Shuttle program, there are also various mockups on display throughout the world:
Space Shuttle Explorer, a full scale replica of an Orbiter at the
Kennedy Space Center visitor's complex
Space Shuttle Adventure, a full scale mockup of an Orbiter mid-deck and flight deck at
Space Center HoustonCurrent and past Space Shuttle's applications include:
*Crew rotation and servicing of Mir and the ISS
*Manned servicing missions, such as to the
Hubble Space Telescope (HST)
*Manned experiments in
LEO*Carry to LEO:
**Large
satellites — these have included the HST
**Components for the construction of the ISS
**Supplies
*Carry satellites with a booster, the Payload Assist Module (PAM-D) or the Inertial Upper Stage (IUS), to the point where the booster sends the satellite to:
**A higher Earth orbit; these have included:
***
Chandra X-ray Observatory***Many
TDRS satellites
***Two DSCS-III (Defense Satellite Communications System) communications satellites in one mission
***A
Defense Support Program satellite
**An interplanetary orbit; these have included:
***
Magellan probe***
Galileo spacecraft***
Ulysses probeAs of 2006, two Shuttles have been destroyed in 115 missions, both with the loss of the entire crew (14 astronauts total):
*
Challenger — lost 73 seconds after liftoff,
January 28,
1986 *
Columbia — lost approximately 16 minutes before landing,
February 1,
2003 This gives a 2% death rate per astronaut per flight, and a failure rate of almost 1 every 60 missions.
Since the
Space Shuttle Columbia disaster in 2003, the ISS had been operating on a skeleton crew of two and is currently being serviced primarily by Russian space vehicles. While the "return to flight" mission
STS-114 in 2005 was successful, a similar piece of foam from a different portion of the tank was shed. Although the debris did not strike the Orbiter, the program was grounded once again.
The second "Return to Flight" mission,
STS-121, launched on
July 4,
2006, at 2:37:55 PM (EDT), after two previous launches were scrubbed because of lingering thunderstorms and high winds around the launch pad and the launch took place despite objections from its chief engineer and safety head. This mission increased the ISS crew to three. A five-inch crack in the foam insulation of the external tank gave cause for concern; however, the Mission Management Team gave the go for launch.
[Chien, Philip (June 27, 2006) "NASA wants shuttle to fly despite safety misgivings." The Washington Times] Space Shuttle Discovery touched down successfully on
July 17,
2006 at 9:14:43 AM (EDT) on Runway 15 at the
Kennedy Space Center.
Following the success of
STS-121, the next mission,
STS-115, is scheduled for launch on
August 28,
2006.
The Shuttle program is scheduled for mandatory retirement in 2010. The Shuttle's planned succesor is
Project Constellation with its
Ares I and
Ares V launch vehicles and
Crew Exploration Vehicle. NASA hopes to launch 16 more shuttle flights before then.
[National Aeronautics and Space Administration. "NASA Names New Rockets, Saluting the Future, Honoring the Past" Press Release 06-270. 30 June 2006.]The total cost of the program has been $145 billion as of early 2005 , and is estimated to be $174 billion when the Shuttle retires in 2010.
NASA's budget for 2005 allocated 30%, or $5 billion, to Space Shuttle operations;
this was decreased in 2006 to a request of $4.3 billion.
Per-launch costs can be measured by dividing the total cost over the life of the program (including buildings, facilities, training, salaries, etc) by the number of launches. With 115 missions (as of
6 August 2006), and a total cost of $150 billion ($145 billion as of early 2005 + $5 billion for 2005
, this gives approximately $1.3 billion per launch. Another method is to calculate the incremental (or marginal) cost differential to add or subtract one flight — just the immediate resources expended/saved/involved in that one flight. This is about $55 million. This means that the marginal or incremental per launch costs have been about 50% more than early projections.
Early cost estimates of $118 per pound ($260/kg) of payload were based on marginal or incremental launch costs, and based on 1972 dollars and assuming a 65,000 pound (30,000 kg) payload capacity. Correcting for inflation and other factors, this equates to roughly $36 million incremental costs per launch. Compared to this, today's actual incremental per launch costs are about 50% more, or $55 million per launch.
The Space Shuttle program has been criticized for design, cost, management, and safety issues. After both the
Challenger disaster and the
Columbia disaster, high profile boards convened to investigate the accidents with both committees returning praise and serious critiques to the program and NASA management. One of the most famous of these criticisms came from
Nobel Prize winner
Richard Feynman.
* The
Crawler-Transporter carries the
Mobile Launcher Platform and the Space Shuttle from the
Vehicle Assembly Building to
Launch Complex 39.
* The
Shuttle Carrier Aircraft are two modified
Boeing 747s. Either can fly an Orbiter from alternative landing sites back to
Cape Canaveral.
* A 36-wheeled transport trailer, originally built for the
U.S. Air Force's launch facility at
Vandenberg Air Force Base in
California (since then converted for
Delta IV rockets) that would transport the Orbiter from the landing facility to the launch pad, which allowed both "stacking" and launch without utilizing a separate VAB-style building and crawler-transporter roadway. Prior to the closing of the Vandenberg facility, Orbiters were transported from the OPF to the VAB on its undercarriage, only to be raised when the Orbiter was being lifted for attachment to the SRB/ET stack. The trailer allows the transportation of the Orbiter from the OPF to either the SCA-747 "Mate-Demate" stand or the VAB without placing any additional stress on the undercarriage.
*
GRiD Compass the early laptop carried aboard the shuttle.
*
Human spaceflight*
List of human spaceflights*
List of human spaceflights chronologically*
List of space shuttle missions*
Shuttle SERV*
Space disaster*
Space explorationFiction
*
Space shuttles in fiction*
'Shuttle' Game DOS-based shuttle simulator from the 1990s.
*
Orbiter a freeware simulator that allows users to fly various spacecraft including the Shuttle.
Physics
*
Atmospheric reentry*
Lifting body*
Reusable launch system*
Single-stage-to-orbitSimilar spacecraft
*
EADS Phoenix *
Hermes*
HOPE-X*
Kliper*
Military space shuttle*
Project Constellation*
Shuttle Buran program*
Reference manual*
How The Space Shuttle Works*
NASA Space Shuttle News Reference - 1981 (PDF document)*
Orbiter Vehicles*
Shuttle Program Funding 1992 - 2002*
Shuttle development costs and history, CAIB transcript 4-23-03* R.A.Pielke, "Space Shuttle Value open to Interpretation", Aviation Week Magazine, issue 26. July 1993, p.57 (PDF file): [
2]
*
MSNBC.com, Jan. 27, 2006: "7 myths about the Challenger shuttle disaster": On the 20th anniversary of the Space Shuttle
Challenger disaster, NBC's space analyst James Oberg debunks seven myths that have grown up around the event.
*
NASA Human Spaceflight - Shuttle: Current status of Shuttle missions
*
NASA TV: View live streaming of launch and mission coverage
* [news:sci.space.shuttle Space Shuttle Newsgroup - sci.space.shuttle]
*
List of all Shuttle Landing Sites*
Map of Landing Sites* Official NASA
Human Space Flight Orbital Tracking system
*
Track the Shuttle with Google Maps
*
Congressional Research Service (CRS) Reports regarding the Space Shuttle*
Washington Monthly: "Beam Me Out Of This Death Trap, Scotty": Critical article on the Space Shuttle program, from 1981
*
The Atlantic Monthly, November 2003: "Columbia's Last Flight" Article on the
Columbia disaster and the subsequent investigation
*
SpaceDaily.com: "Explaining 30 years of Fudge": How the shuttle program was mis-sold to congress and where the $118/lb supposed costs came from
* http://www.shuttlesim.be/
*
NASA wants shuttle to fly despite safety misgivings - June 27, 2006
*
Weather criteria for Shuttle launch
