The Space Shuttle

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Chapter 4

• The Space Shuttle

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Components The Orbiter

• The main components of the shuttle are the
  orbiter, the external tank, and the solid rocket
  boosters.
• The Orbiter is 112 feet long, 56 feet high, and
  78 feet wide from wingtip to wingtip. It serves
  as the crewmembers headquarters and to transport
  large payloads to space. The orbiter is designed
  to carry from two to eight crewmembers on a ten
  to fourteen day mission.

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Components The Orbiter

• In the front of the orbiter is a three level crew
  compartment. The upper level, called the flight
  deck, houses maneuvering controls, mission
  monitors, six windshields, two overhead windows.
  The second level, the mid-deck, is where the crew
  eats, sleeps, exercises and conducts some
  experiments. The mid-deck also features an
  outside hatch and airlock leading to the cargo
  bay. The lower level serves to store equipment.

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Components The Orbiter

• Behind the crew compartment is the payload bay.
  It measures 60 feet long, 17 feet wide, and 13
  feet deep and can carry up to 51,600 pounds.
• The wings, also known as delta wings, are
  D-shaped which are the most efficient for
  traveling at speeds well beyond the speed of
  sound.

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Components The Orbiter

• The orbiter also contains the space shuttles
  main engines. These three engines, located on the
  rear of the orbiter, burn a propellant of liquid
  hydrogen and liquid oxygen. They are essential in
  getting the orbiter into orbit burning up to
  45,300 gallons per minute. They can be throttled
  from as low as 65 of rated thrust up to 109
  which allows the shuttle to provide a much
  smoother ride.
• The orbiter is covered by 32,000 heat tiles that
  protect the shuttle upon reentry.

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Components The External Tank

• Orange in color, this tank provides the fuel for
  the shuttles main engines. Thus, once the
  external tank is discarded, the main engines are
  no longer of use.
• The external tank is covered by a foam slightly
  stiffer than the material in a Styrofoam cooler.
  This serves as insulation for the liquid hydrogen
  and oxygen held inside which needs to remain at
  temperatures as cold as 420 degrees below zero.
• This is the only non-reusable part of the
  shuttle.

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Components The Solid Rocket Boosters (SRBs)

• Twin boosters attached to the external tank serve
  to help to lift the shuttle in the initial stage
  of launch. They are the largest solid rockets
  ever made.
• The solid propellant contains by weight, 16
  aluminum powder fuel, 70 ammonium perchlorate
  oxidizer, 12 polybutadiene acrylic acid
  acrylonitrile which is a binding agent, 2 epoxy
  used for curing, and iron oxide to help control
  the burning rate.

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Components The Solid Rocket Boosters (SRBs)

• The mixture of these materials looks like a dense
  viscous plaster which is poured into a mold where
  it is dried (cured) for several days resulting in
  a material that looks and feels like a rubber
  eraser or hard putty.
• The SRBs are for one time use only and can burn
  at a 100 rate until all the fuel is exhausted.

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Configuration

• Total Configuration is 184 feet tall, 79 feet
  wide from either side, and weighs 4.4 million
  pounds. When the launch finally occurs 6.425
  million pounds of thrust lift the entire ship
  into the air very quickly because of the excess
  power.

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Shuttles

• Each orbiter is named for a famous
  American/British sailing ship of exploration.
  Challenger (OV-99) was supposed to be the
  original test vehicle, but during construction,
  NASA decided to make this orbiter into an
  operational spacecraft.
• The first shuttle to launch into space was the
  Columbia (OV-102) on March 12, 1981. Since then
  the Challenger, Discovery (OV-103), Atlantis
  (OV-104) and replacing the Challenger Endeavor
  (OV-105) have become part of the fleet.

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Shuttles
Shuttle Flight Days Flights MIR/ISS dockings Satellites Deployed
Atlantis 220 26 7/6 14
Challenger 62 10 0/0 10
Columbia 301 28 0/0 8
Discovery 242 30 1/4 26
Endeavour 207 19 1/4 3
Totals 1,032 113 9/16 61
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Launch Preparation

• Each space shuttle flight requires years of
  mission planning and months of getting the
  shuttle prepared or processed to go into orbit.
• Over a month is spent inspecting every system on
  the orbiter and repair or replace items failing
  the rigorous exams. Every one of the 32,000 heat
  tiles must be inspected and replaced if they are
  damaged or missing.

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Launch Preparation

• The shuttle engines and their respective fuel
  pumps must be removed, inspected, and
  refurbished. The engineers may install the same
  engines, new engines, or previously refurbished
  engines.
• The process of integrating the major shuttle
  parts is called stacking and takes about four to
  six weeks.

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Launch Preparation

• A specific vehicle, called the crawler, is used
  to move the completed shuttle assembly to the
  launch pad. It is described as the biggest,
  slowest, strongest, strangest and noisiest land
  vehicle ever created by mankind, it is unlike any
  other moving vehicle on earth.
• Built in the 1960s, the crawler typically rolls
  at around 2 mph. (Video) It takes several hours
  for the crawler to take the completed shuttle on
  the 4 mile journey to the launch pad.

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The Launch

• All shuttle launches take place at the Kennedy
  Space Center in Florida. Once the tower is
  cleared, the control of the shuttle flight goes
  to Johnson Space Center (JSC) in Houston, Texas.
• At two minutes into the launch both SRBs begin to
  burn out at an altitude of 29 miles. After the
  boosters burn completely out, they fall into the
  Atlantic Ocean beneath large parachutes where
  they are recovered by two NASA ships.
• Video of launch of Atlantis (10/02) Parts 1, 2,
  3.

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The Launch

• The main shuttle engines completely shut down at
  eight minutes and thirty seconds into flight.
  Soon after the external tank is released.
• At 45 minutes after launch the orbiter reaches
  apogee and two thrusters located in the blisters
  at the left and right of the craft's vertical
  stabilizer begin to fire to raise the shuttle's
  orbit. This rocket system is called the orbital
  maneuvering system (OMS) and it increases the
  spacecraft's velocity by 150 miles per hour.

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In Orbit

• Once arriving at this orbit, the payload bay
  doors must be opened to allow the orbiter to cool
  by removing the excess heat caused by electrical
  equipment and life support systems operations.
• Now the space shuttle may begin serving its
  purpose. This typically is one of the following

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In Orbit

• Dock with another spacecraft ( ie. International
  Space Station, Mir)
• Carry out experiments (usually a laboratory such
  as Spacelab has been then included in the payload
  bay)
• Release a satellite in the payload bay. This is
  sometimes done using the robotic arm.
• Trap another spacecraft. This was done for
  example with the Hubble Space Telescope so that
  it could be serviced.

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In Orbit

• The OMS continues to control the orbit of the
  shuttle, however, attitude is controlled by the
  reaction control system (RCS). These are a series
  of small rockets which burn hydrazine and
  nitrogen tetroxide. There is one RCS pod in the
  shuttle's nose and two RCS pods in the tail that
  contain different rocket nozzles that thrust up,
  down, left, and right. Once an RCS thruster is
  activated and a movement starts an equal and
  opposite RCS thruster must be activated to stop
  the motion (Newton's third law is paramount in
  zero g).

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The Return Flight

• The space shuttle cannot land in rainy weather.
  The weather resisting coating burns off during
  launch and re-entry. Thus while the preferred
  landing site is back in Kennedy Space Center, the
  shuttle sometimes needs to be diverted to White
  Sands, New Mexico or Edwards Air Force Base in
  California. A specially redesigned Boeing 747
  would then piggyback the shuttle to Florida.
  (Video)

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The Return Flight

• A number of checklist items must be performed
  before the space shuttle can return to Earth.
  Among these the astronauts must put back on the
  pressure suits which they wore during ascent and
  close the payload bay doors.
• The RCS then places the shuttle in the proper
  attitude and the OMS slows the shuttle into a
  decaying orbit. (Video of go-for de-orbit
  burn). From a point halfway around the world the
  shuttle begins its entry.

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The Return Flight

• As the shuttle enters the atmosphere, the RCS
  maneuvers the nose at an attitude of about 30º
  nose up. This insures that the thermal energy is
  concentrated on the heat tiles underneath the
  orbiter. Upon reentering the atmosphere
  temperatures as high as 3,000 degrees Fahrenheit
  may occur outside the shuttle as it races at
  speeds in excess of 17,000 miles an hour.
• Its a controlled glider as it does its landing
  (Video). The whole maneuver from de-orbit burn to
  touchdown takes about an hour.

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The Tragedies

• Two shuttles have been destroyed, both with the
  loss of all astronauts on board
• Challenger - lost 73 seconds after lift-off,
  January 28, 1986. Due to unusually cold weather,
  one of the O-rings in the SRBs became brittle.
  One minute after lift-off the ring failed
  allowing hot gas to escape the SRB and pierce the
  external tank. Some 73 seconds after the launch
  began, a colossal explosion ensued that destroyed
  the shuttle.

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The Tragedies

• Columbia - lost during re-entry, February 1,
  2003. Eighty-one seconds after lift-off a
  briefcase-sized piece of insulation foam from the
  external tank possibly containing ice detached
  and impacted the left wing of the orbiter. It is
  believed that this damaged tiles vital in
  protecting the shuttle during re-entry. As the
  shuttle returned, data indicates that the left
  wing suffered severe damage that eventually led
  to the loss of control and destruction of the
  orbiter.

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The Tragedies

• Missions are hopeful to restart around May of
  this year with the shuttle Discovery making a
  trip to the International Space Station.
  Designated, mission STS-114, the crewmembers will
  deliver supplies to the station, but the major
  focus of their mission will be testing and
  evaluating new Space Shuttle flight safety, which
  includes new inspection and repair techniques.
  The first spacewalk is set to demonstrate repair
  techniques of the shuttles Thermal Protection
  System.