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Space Shuttle program

2007 Schools Wikipedia Selection. Related subjects: Space transport

   Space Shuttle Insignia

   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, the Shuttle can independently move itself out of
   orbit (by means of its maneuvering thrusters) and re-enter the Earth's
   atmosphere. During descent and landing, the Shuttle Orbiter acts as a
   glider and makes a completely unpowered landing.

   The Shuttle is the only winged manned spacecraft to achieve orbit and
   land. Its missions involve carrying large payloads to various orbits
   (including segments to be added to the International Space Station
   (ISS)), providing crew rotation for the International Space Station,
   and performing service missions. The orbiter can also recover
   satellites and other payloads from orbit and return them to Earth, but
   its use in this capacity is rare. However, the Shuttle has previously
   been used to return large payloads from the ISS to Earth, as the
   Russian Soyuz spacecraft has limited capacity for return payloads. Each
   vehicle was designed with 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 by 2010, after which it will be replaced by the new
   Orion spacecraft.

Conception

   The Space Shuttle Columbia seconds after the launch of its maiden
   flight, on April 12, 1981 (NASA). This was one of only two missions
   that had a painted external tank (tallest vehicle component that's
   shown in white).
   Enlarge
   The Space Shuttle Columbia seconds after the launch of its maiden
   flight, on April 12, 1981 ( NASA). This was one of only two missions
   that had a painted external tank (tallest vehicle component that's
   shown in white).

   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.

   In October 1969, at a Space Shuttle symposium held in Washington,
   George Mueller (NASA deputy administrator) presented opening remarks:
   "The goal we have set for ourselves is the reduction of the present
   costs of operating in space from the current figure of $1,000 a pound
   for a payload delivered in orbit by the Saturn V, down to a level of
   somewhere between $20 and $50 a pound. By so doing we can open up a
   whole new era of space exploration. Therefore, the challenge before
   this symposium and before all of us in the Air Force and NASA in the
   weeks and months ahead is to be sure that we can implement a system
   that is capable of doing just that. Let me outline three areas which,
   in my view, are critical to the achievement of these objectives.

          One is the development of an engine that will provide sufficient
          specific impulse, with adequate margin to propel its own weight
          and the desired payload.
          A second technical problem is the development of the reentry
          heat shield, so that we can reuse that heat shield time after
          time with minimal refurbishment and testing.
          The third general critical development area is a checkout and
          control system which provides autonomous operation by the crew
          without major support from the ground and which will allow low
          cost of maintenance and repair.

   Of the three, the latter may be a greater challenge than the first
   two."

   The 1972 NASA/GAO REPORT TO THE CONGRESS, Cost-Benefit Analysis Used In
   Support Of The Space Shuttle Program states: NASA has proposed that a
   space shuttle be developed for U.S. Space Transportation needs for
   NASA, the Department of Defense (DOD), and other users in the
   1980's.The primary objective of the Space Shuttle Program is to provide
   a new space transportation capability that will:
     * reduce substantially the cost of space operations and
     * provide a future capability designed to support a wide range of
       scientific, defense, and commercial uses.

Development

   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 an 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, now Boeing), 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. 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 Centre 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 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.

Shuttle applications

   Current 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:
               o Chandra X-ray Observatory
               o Many TDRS satellites
               o Two DSCS-III (Defense Satellite Communications System)
                 communications satellites in one mission
               o A Defense Support Program satellite
          + An interplanetary orbit; these have included:
               o Magellan probe
               o Galileo spacecraft
               o Ulysses probe

Flight statistics

   Shuttle Flight Days Orbits Distance
   -mi- Distance
   -km- Flights Longest flight
   -days- Crew and
   passengers EVAs Mir/ISS
   docking Sat.
   dep.†
   Atlantis 232.20 3,834 94,808,732 152,534,078 28 12.89 173 24 7 / 8 14
   Challenger 62.41 995 25,803,940 41,527,416 10 8.23 60 6 0 / 0 10
   Columbia 300.74 4,808 125,204,911 201,497,772 28 17.66‡ 160 7 0 / 0 8
   Discovery 268.62 4,229 109,810,673 176,657,672 32 13.89 199 31 1 / 6 26
   Endeavour 206.60 3,259 85,072,077 136,910,237 19 13.86 130 29 1 / 6 3
   Total 1,070.57 16,245 440,700,333 709,127,174 117 17.66‡ 812 100 9 / 20
   61

   (as of September 21, 2006)
   † Satellites deployed
   ‡ This was flight STS-80, during November 1996.

   Other shuttles
   Shuttle Flight Days Orbits Distance
   -mi- Distance
   -km- Flights Longest flight
   -days- Crew and
   passengers EVAs Mir/ISS
   docking Satellites
   deployed
   Enterprise 0.014 0 Unknown Unknown 0 0.004 >3 0 0 / 0 0
   Buran 1.01 0.14 2 51,764 83,307 1 0.14 0 0 0 / 0 0

Disasters

   Challenger exploded 73 seconds after liftoff.
   Enlarge
   Challenger exploded 73 seconds after liftoff.

   As 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, STS-51-L, January 28,
       1986

     * Columbia — lost approximately 16 minutes before its expected
       landing, STS-107, February 1, 2003

   This gives a 2% death rate per astronaut per flight, and an average
   failure rate of almost 1 every 60 missions. The original disaster
   potential, though disaster is not defined as fatal or non-fatal, was
   estimated during Shuttle development at one every 75 missions. 87
   successful missions were flown between STS-51-L and STS-107.

Current status

   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 for this
   reason.

   The second "Return to Flight" mission, STS-121, launched on July 4,
   2006, at 2:37:55 p.m. (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 (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. Space Shuttle Discovery touched down successfully on
   July 17, 2006 at 9:14:43 a.m. (EDT) on Runway 15 at the Kennedy Space
   Centre.

   Following the success of STS-121, STS-115 launched on September 9, 2006
   at 11:15 a.m. EST, following two weeks of delays. This mission resumed
   the construction of the International Space Station which had been
   halted since the Columbia disaster three and a half years prior. On
   Tuesday, October 31st, 2006, NASA announced approval of a shuttle
   servicing mission to the Hubble Space Telescope.

   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 the Orion Spacecraft. NASA hopes to launch
   16 more shuttle flights before then.

Costs

   The total cost of the Shuttle 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 $60 million .

   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, this equates to roughly $36 million incremental per launch
   costs. Compared to this, today's actual incremental per launch costs
   are about two thirds more, or $60 million per launch.

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.

   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.

Terrestrial transportation vehicles

     * 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.

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