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Space Shuttle program

                   
Space Shuttle program
Shuttle delivers ISS P1 truss.jpg
Duration 1981 - 2011
Goal Take advantage of reusable spacecraft
Tasks Launching of satellites such as Hubble telescope, building of ISS
Losses Challenger, at liftoff, 1986; Columbia, at reentry, 2003
Organization NASA
Legacy First spacecraft that could land like an airplane
Space Shuttle Program Commemorative Patch.png

NASA's Space Shuttle program, officially called Space Transportation System (STS), was the United States government's manned launch vehicle program from 1981 to 2011. The winged Space Shuttle orbiter was launched vertically, usually carrying four to seven astronauts (although eight have been carried) and up to 50,000 lb (22,700 kg) of payload into low Earth orbit (LEO). When its mission was complete, the Shuttle could independently move itself out of orbit using its Maneuvering System (it oriented itself appropriately and fired its main OMS engines, thus slowing it down) and re-enter the Earth's atmosphere. During descent and landing the orbiter acted as a re-entry vehicle and a glider, using its OMS system and flight surfaces to make adjustments.

The shuttle is the only winged manned spacecraft to have achieved orbit and land, and the only reusable space vehicle that has ever made multiple flights into orbit. Its missions involved carrying large payloads to various orbits (including segments to be added to the International Space Station), provided crew rotation for the International Space Station, and performing service missions. The orbiter also recovered satellites and other payloads (e.g. from the ISS) from orbit and returned them to Earth, though its use in this capacity was rare. Each vehicle was designed with a projected lifespan of 100 launches, or 10 years' operational life.

The program formally commenced in 1972, although the concept had been explored since the late 1960s, and was the sole focus of NASA's manned operations after the final Apollo and Skylab flights in the mid-1970s. The Shuttle was originally conceived of and presented to the public in 1972 as a 'Space Truck' which would, among other things, be used to build a United States space station in low earth orbit in the early-1990s and then be replaced by a new vehicle. When the concept of the U.S. space station evolved into that of the International Space Station, which suffered from long delays and design changes before it could be completed, the service life of the Space Shuttle was extended several times until 2011 when it was finally retired — serving at least 15 years longer than it was originally designed to do. In 2004, according to the President George W. Bush's Vision for Space Exploration, use of the space shuttle was to be focused almost exclusively on completing assembly of the ISS, which was far behind schedule at that point.

The first experimental orbiter was delivered for test flights in 1976, and the first launch took place on April 12, 1981, with Columbia and STS-1, the first shuttle orbital flight. The space shuttle program finished with its last mission, STS-135 flown by Atlantis, in July 2011, retiring the final shuttle in the fleet. The Space Shuttle program formally ended on August 31, 2011. [1]

Retirement of the shuttle -the most complex vehicle ever built- ended the era in which all of America's varied space activities were performed by one craft -or even one organization. Functions performed by the shuttle for 30 years will be done by not one but many different spacecraft currently flying or in advanced development. Secret military missions are being flown by the US Air Force's "highly successful" unmanned mini-shuttle, the X-37B. By the end of 2012 cargo supply to the International Space Station will be flown by privately owned commercial craft: SpaceX's successfully tested re-usable Dragon capsule, and Orbital Science's craft (also slated for testing in 2012). Crew service to ISS will be flown by Dragon and any of several other commercial craft now in development, including Sierra Nevada's manned mini-shuttle, and the horizontal-takeoff Stratolaunch being designed by Burt Rutan, designer of the word's first privately owned manned spacecraft, SpaceShipOne.

Contents

  Conception and development

Before the Apollo XI moon landing in 1969, NASA began early studies of space shuttle designs. In 1969 President Richard Nixon formed the Space Task Group, chaired by Vice President Spiro T. Agnew. This group evaluated the shuttle studies to date, and recommended a national space strategy including building a space shuttle.[2] The goal, as presented by NASA to Congress, was to provide a much less-expensive means of access to space that would be used by NASA, the Department of Defense, and other commercial and scientific users.[3]

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, reusable solid rocket boosters, and an expendable external tank.[2]

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.[2] The intent was to launch as many as 50 missions per year, with hopes of driving down per-mission costs.[4]

The final design was less costly to build and less technically ambitious than earlier fully reusable designs. The initial design parameters included a larger external fuel tank, which would have been carried to orbit, where it could be used as a section of a space station, but this idea was killed due to budgetary and political considerations.

  Early U.S. space shuttle concepts

The prime contractor for the program was North American Aviation (later Rockwell International, now Boeing), the same company responsible for building 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 (now Pratt & Whitney Rocketdyne, part of United Technologies).[2]

The first orbiter was originally planned to be 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.[5] Amid great fanfare, the Enterprise (designated OV-101) 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.

  Program history

The first fully functional orbiter was Columbia (designated OV-102), built in Palmdale, California. It was delivered to Kennedy Space Center (KSC) 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 (OV-099) was delivered to KSC in July 1982, Discovery (OV-103) in November 1983, and Atlantis (OV-104) in April 1985. Challenger was originally built and used as a Structural Test Article (STA-099) but was converted to a complete shuttle when this was found to be less expensive than converting Enterprise from its Approach and Landing Test configuration, according to NASA. Challenger was destroyed during ascent due to O-Ring failure on the right solid rocket booster (SRB) on January 28, 1986, with the loss of all seven astronauts on board. Endeavour (OV-105) was built to replace Challenger (using structural spare parts originally intended for the other orbiters) and delivered in May 1991; it was first launched a year later. Seventeen years after the Challenger accident, Columbia broke up on reentry, killing all seven crew members, on February 1, 2003, and it was not replaced. NASA maintains warehoused extensive catalogs of recovered pieces from the two destroyed orbiters. Out of the five fully functional shuttle orbiters built, three remain. Enterprise, which was used for atmospheric test flights but not for orbital flight, had many parts taken out for use on the other orbiters. It was later visually restored and was on display at the National Air and Space Museum's Steven F. Udvar-Hazy Center until April 19, 2012. Enterprise was moved to New York City in April 2012 where it will be displayed at the USS Intrepid Sea, Air, and Space Museum. The shuttle Discovery replaced Enterprise at the National Air and Space Museum's Steven F. Udvar-Hazy Center

  In 1986, Challenger disintegrated 1 minute 13 seconds after liftoff.

  Accidents

In 135 missions, two shuttles were destroyed, both with the loss of crew, a total of 14 astronauts:

  • Challenger – lost 73 seconds after liftoff, STS-51-L, January 28, 1986
  • Columbia – lost approximately 16 minutes before its expected landing, STS-107, February 1, 2003

  Status Quo

Astronaut crews have performed vital servicing tasks on Hubble through four servicing missions since December 1993 in order to extend operating life with the replacement of aging hardware and enhancing scientific capability through the installation of advanced science instruments.

  Space Shuttle Atlantis takes flight on the STS-27 mission on December 2, 1988. The Shuttle takes about 8.5 minutes to accelerate to a speed of over 27,000 km/h (17000 mph) and achieve orbit.
  A drag chute is deployed by Endeavour as it completes a mission of almost 17 days in space on Runway 22 at Edwards Air Force Base in southern California. Landing occurred at 1:46 pm (EST), March 18, 1995.

From September 2005 until early 2008, the manager of the space shuttle program was Wayne Hale. Hale then became NASA's deputy associate administrator for strategic partnerships. John Shannon, who had been Hale's deputy since November 2005, succeeded him as the Space Shuttle Program Manager.[6]

After the Space Shuttle Columbia disaster in 2003, the International Space Station operated on a skeleton crew of two for more than two years and was serviced primarily by Russian spacecraft. 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 for this reason.

The second "Return to Flight" mission, STS-121 launched on July 4, 2006, at 2:37 pm (EDT). 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. A five-inch (13 cm) crack in the foam insulation of the external tank gave cause for concern; however, the Mission Management Team gave the go for launch.[7] This mission increased the ISS crew to three. Discovery touched down successfully on July 17, 2006 at 9:14 am (EDT) on Runway 15 at Kennedy Space Center.

Following the success of STS-121, all subsequent missions have been completed without major foam problems, and the construction of ISS nears completion (during the STS-118 mission in August 2007, the orbiter was again struck by a foam fragment on liftoff, but this damage was minimal compared to the damage sustained by Columbia).

The Columbia Accident Investigation Board, in its report, noted the reduced risk to the crew when a shuttle flies to the International Space Station (ISS), as the station can be used as a safe haven for the crew awaiting rescue in the event that damage to the shuttle orbiter on ascent makes it unsafe for re-entry. The board recommended that for the remaining flights, the shuttle always orbit with the station. Prior to Return to Flight, NASA Administrator Sean O'Keefe declared that all future flights of the shuttle would go to the ISS, precluding the possibility of executing the final Hubble Space Telescope servicing mission which had been scheduled before the Columbia accident, despite the fact that millions of dollars worth of upgrade equipment for Hubble were ready and waiting in NASA warehouses. Many dissenters, including astronauts, asked NASA management to reconsider allowing the mission, but initially the director stood firm. On October 31, 2006, NASA announced approval of the launch of the space shuttle, Atlantis, the fifth and final shuttle servicing mission to the Hubble Space Telescope, scheduled for August 28, 2008. However SM4/STS-125 eventually launched in May 2009.

  Retirement

  Atlantis begins the last mission of the Space Shuttle program

The Space Shuttle program was extended several times beyond its originally-envisioned 15 year life span because of the delays in building the United States space station in low Earth orbit — a project which eventually evolved into the International Space Station. It was formally scheduled for mandatory retirement in 2010 in accord with the directives President George W. Bush issued on January 14, 2004 in his Vision for Space Exploration.[8]. However, the final Shuttle launch was that of Atlantis on July 8, 2011. According to the Vision for Space Exploration, the next manned NASA program was to be Project Constellation with its Ares I and Ares V launch vehicles and the Orion Spacecraft; however, the Constellation program was controversial and never fully funded, and in early 2010 the Obama administration asked Congress to instead endorse a plan with heavy reliance on the private sector for delivering cargo and crew to LEO .

NASA originally planned to make the Hubble a Smithsonian museum display, but decided to keep it in space until a successor is launched.[9][10] Since the space shuttle fleet has retired (while Hubble still has many years of service life ahead), there will be no existing or planned spacecraft capable of returning the Hubble to Earth intact, so it is now very unlikely it will ever be on the ground again.

In an internal e-mail apparently sent August 18, 2008 to NASA managers and leaked to the press, NASA Administrator Michael Griffin stated his belief that the Bush administration had made no viable plan for U.S. crews to participate in the International Space Station beyond 2011, and that Office of Management and Budget (OMB) and Office of Science and Technology Policy (OSTP) were actually seeking its demise.[11][12] The email appeared to suggest that Griffin believed the only reasonable solution was to extend the operation of the shuttle beyond 2010, but noted that Executive Policy (i.e., the White House) is firm that there will be no extension of the shuttle retirement date, and thus no U.S. capability to launch crews into orbit until the Ares I/Orion system becomes operational in 2014 at the very earliest. He appeared to indicate that he did not see purchase of Russian launches for NASA crews as politically viable following the 2008 South Ossetia war, and hoped the new US administration will resolve the issue in 2009 by extending shuttle operations beyond 2010.[11] However, according to an article by former Space Shuttle program Director Wayne Hale on his official NASA blog, the space shuttle program, in preparation for the 2010 shutdown, has already terminated many specialty parts and materials contracts, many with small businesses whose only customer may have been the shuttle program and who closed shop and retired upon receiving their termination letters; as a result, it would be difficult and expensive at this point to extend the shuttle program, and there would be a lag of at least a year (without flights) before exhausted exotic parts and supplies could be replaced. The loss of talent from dismissed employees is another obstacle to program extension.[13]

On September 7, 2008, NASA released a statement regarding the leaked e-mail, in which Griffin said:

"The leaked internal E-mail fails to provide the contextual framework for my remarks, and my support for the administration's policies. Administration policy is to retire the space shuttle in 2010 and purchase crew transport from Russia until Ares and Orion are available. The administration continues to support our request for an INKSNA exemption. Administration policy continues to be that we will take no action to preclude continued operation of the International Space Station past 2016. I strongly support these administration policies, as do OSTP and OMB."
—Michael D. Griffin, [14]

A $2.5 billion spending provision allowing NASA to fly the space shuttle beyond its then-scheduled retirement in 2010 passed the Congress in April 2009, although neither NASA nor the White House requested the one-year extension.[15]

  NASA Authorization Act of 2008

U.S. Representative Dave Weldon introduced H.R. 4837, known as the SPACE Act.[16] This legislation would have kept the shuttle flying past 2010 at a reduced rate until the Orion spacecraft would have been ready to replace it. It would also have allowed the Alpha Magnetic Spectrometer to be launched to the ISS, which the schedule at the time did not allow.[17]

On October 15, 2008, President Bush signed the NASA Authorization Act of 2008, giving NASA funding for one additional mission to "deliver science experiments to the station."[18][19][20][21] The act allowed for an additional space shuttle flight, STS-134, to the ISS to install the Alpha Magnetic Spectrometer, which was previously canceled.[22]

  Successors

  The Dragon spacecraft, one of the Space Shuttle's several successors, is seen here on its way to deliver cargo to the ISS

The Commercial Orbital Transportation Services (COTS) program began in 2006 with the purpose of creating commercially operated unmanned cargo vehicles to service the ISS.[23] These vehicles, the SpaceX's Dragon and the Orbital Sciences' Cygnus, are expected to become operational in 2012.[24] The Commercial Crew Development (CCDev) program was initiated in 2010 with the purpose of creating commercially operated manned spacecraft capable of delivering at least four crew members to the ISS, staying docked for 180 days and then returning them back to Earth.[25] These spacecraft are expected to become operational around 2017.[26]

Although the Constellation program was canceled it has been replaced with a very similar beyond low-Earth orbit program. The Orion spacecraft has been left virtually unchanged from its previous design. The planned Ares V rocket has been replaced with the smaller Space Launch System (SLS), which is planned to launch both Orion and other necessary hardware.[27] The Exploration Flight Test-1 (EFT-1), an unmanned test flight of Orion's crew module, is planned to be launched in 2014 on a Delta IV Heavy rocket.[28] Exploration Mission-1 (EM-1) is the unmanned initial launch of SLS, which is planned for 2017.[28] Exploration Mission-2 (EM-2) is the first manned flight of Orion and SLS and is scheduled for 2019.[28] EM-2 is 10-14 day mission planned to place a crew of four into Lunar orbit. As of March 2012, the destination for EM-3 and immediate destination focus for this new program is still in-flux.[29]

  Shuttle applications

  Space Shuttle Endeavour docked with the International Space Station (ISS)

Space shuttle applications have included:

  Budget

  Space Shuttle Discovery as it approaches the International Space Station during STS-114 on July 28, 2005

Early during development of the space shuttle, NASA had estimated that the program would cost $7.45 billion ($43 billion in 2011 dollars, adjusting for inflation) in development/non-recurring costs, and $9.3M ($54M in 2011 dollars) per flight.[31] Early estimates for the cost to deliver payload to low earth orbit were as low as $118 per pound ($260/kg) of payload ($635/pound in 2011 dollars), based on marginal or incremental launch costs, and assuming a 65,000 pound (30 000 kg) payload capacity and 50 launches per year.[32][33]

The actual total cost of the shuttle program through 2011, adjusted for inflation, is $196 billion.[4] The exact breakdown into non-recurring and recurring costs is not available, but, according to NASA, the average cost to launch a Space Shuttle as of 2011 is about $450 million per mission.[34]

NASA's budget for 2005 allocated 30%, or $5 billion, to space shuttle operations;[35] this was decreased in 2006 to a request of $4.3 billion.[36] Non-launch costs account for a significant part of the program budget: for example, during fiscal years 2004 to 2006, NASA spent around $13 billion on the space shuttle program,[37] even though the fleet was grounded in the aftermath of the Columbia disaster and there were a total of three launches during this period of time. In fiscal year 2009, NASA budget allocated $2.98 billion for 5 launches to the program, including $490 million for "program integration", $1.03 billion for "flight and ground operations", and $1.46 billion for "flight hardware" (which includes maintenance of orbiters, engines, and the external tank between flights.)

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 134 missions, and the total cost of US$192 billion (in 2010 dollars), this gives approximately $1.5 billion per launch over the life of the program.[38]

  Assets and transition plan

The Space Shuttle Program occupies over 654 facilities, uses over 1.2 million line items of equipment and employs over 5,000 people. The total value of equipment is over $12 billion. Shuttle related facilities represent over a quarter of NASA's inventory. There are over 1,200 active suppliers to the program throughout the United States. NASA's transition plan has the program operating through 2010 with a transition and retirement phase lasting through 2015. During this time the Ares I and Orion as well as the Altair Lunar Lander were to be under development[39] (although now these programs have been canceled).

  Criticism

The space shuttle program has been criticized for failing to achieve its promised cost and utility goals, as well as design, cost, management, and safety issues.[40] Others have argued that the shuttle program was a step backwards from the Apollo Program, which, while extremely dangerous, accomplished far more scientific and space exploration endeavors than the shuttle ever could. If Apollo had continued, it may have evolved into manned missions to other planets[citation needed].

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. Some of the most famous of the criticisms, most of management, came from Nobel Prize winner Richard Feynman, in his report that followed his appointment to the commission responsible for investigating the Challenger disaster.[41]

  Other STS program vehicles

  Crawler-transporter No.2 ("Franz") in a December 2004 road test after track shoe replacement
  STS Program mate/de-mate facility for STS Orbiter and STS Shuttle Carrier Aircraft (Space Shuttle Atlantis in 1991)

Many other vehicles were used in support of the Space Shuttle program, mainly terrestrial transportation vehicles.

  • The Crawler-Transporter carried the Mobile Launcher Platform and the space shuttle from the Vehicle Assembly Building (VAB) at Launch Complex 39 to Pad A.
  • The Shuttle Carrier Aircraft are two modified Boeing 747s. Either can fly an orbiter from alternative landing sites back to the Kennedy Space Center.
  • A 36-wheeled transport trailer, the Orbiter Transfer System, 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) 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 their undercarriages, only to be raised when the orbiter was being lifted for attachment to the SRB/ET stack. The trailer allowed 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.
  • The Crew Transport Vehicle (CTV), a modified airport jet bridge, was used to assist astronauts to egress from the orbiter after landing. Upon entering the CTV, astronauts could take off their launch and re-entry suits then proceed to chairs and beds for medical checks before being transported back to the crew quarters in the Operations and Checkout Building.
  • The Astrovan was used to transport astronauts from the crew quarters in the Operations and Checkout Building to the launch pad on launch day. It was also used to transport astronauts back again from the Crew Transport Vehicle at the Shuttle Landing Facility.

  See also

Fiction
Physics
Similar spacecraft

  References

 This article incorporates public domain material from websites or documents of the National Aeronautics and Space Administration.

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  41. ^ [1], additional text.

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sensagent's office

Raccourcis et gadgets. Gratuit.

* Raccourci Windows : sensagent.

* Widget Vista : sensagent.

dictionnaire et traducteur pour sites web

Alexandria

Une fenêtre (pop-into) d'information (contenu principal de Sensagent) est invoquée un double-clic sur n'importe quel mot de votre page web. LA fenêtre fournit des explications et des traductions contextuelles, c'est-à-dire sans obliger votre visiteur à quitter votre page web !

Essayer ici, télécharger le code;

SensagentBox

Avec la boîte de recherches Sensagent, les visiteurs de votre site peuvent également accéder à une information de référence pertinente parmi plus de 5 millions de pages web indexées sur Sensagent.com. Vous pouvez Choisir la taille qui convient le mieux à votre site et adapter la charte graphique.

Solution commerce électronique

Augmenter le contenu de votre site

Ajouter de nouveaux contenus Add à votre site depuis Sensagent par XML.

Parcourir les produits et les annonces

Obtenir des informations en XML pour filtrer le meilleur contenu.

Indexer des images et définir des méta-données

Fixer la signification de chaque méta-donnée (multilingue).


Renseignements suite à un email de description de votre projet.

Jeux de lettres

Les jeux de lettre français sont :
○   Anagrammes
○   jokers, mots-croisés
○   Lettris
○   Boggle.

Lettris

Lettris est un jeu de lettres gravitationnelles proche de Tetris. Chaque lettre qui apparaît descend ; il faut placer les lettres de telle manière que des mots se forment (gauche, droit, haut et bas) et que de la place soit libérée.

boggle

Il s'agit en 3 minutes de trouver le plus grand nombre de mots possibles de trois lettres et plus dans une grille de 16 lettres. Il est aussi possible de jouer avec la grille de 25 cases. Les lettres doivent être adjacentes et les mots les plus longs sont les meilleurs. Participer au concours et enregistrer votre nom dans la liste de meilleurs joueurs ! Jouer

Dictionnaire de la langue française
Principales Références

La plupart des définitions du français sont proposées par SenseGates et comportent un approfondissement avec Littré et plusieurs auteurs techniques spécialisés.
Le dictionnaire des synonymes est surtout dérivé du dictionnaire intégral (TID).
L'encyclopédie française bénéficie de la licence Wikipedia (GNU).

Copyright

Les jeux de lettres anagramme, mot-croisé, joker, Lettris et Boggle sont proposés par Memodata.
Le service web Alexandria est motorisé par Memodata pour faciliter les recherches sur Ebay.
La SensagentBox est offerte par sensAgent.

Traduction

Changer la langue cible pour obtenir des traductions.
Astuce: parcourir les champs sémantiques du dictionnaire analogique en plusieurs langues pour mieux apprendre avec sensagent.

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