Orbiter

Space Shuttle Orbiter
The Discovery orbiter approaches the ISS on STS-121
OrganizationNASA
Mission typeOrbiter
Satellite ofEarth
Launch vehicleSpace Shuttle Solid Rocket Booster
Launch siteKennedy Space Center

The Space Shuttle orbiters are the orbital spacecraft of the Space Shuttle program operated by NASA, the space agency of the United States. Each orbiter is a reusable winged "spaceplane", a mixture of rocket, spacecraft, and aircraft. The spaceplane can carry crews and payloads into Earth orbit, perform on-orbit operations, then re-enter the atmosphere and land as a glider, returning its crew and any on-board payload to Earth.

In addition to the crew and payload the reusable orbiter carries most of the main propulsion system, but the propellant for its three main engines is fed from an external tank, and two reusable solid rocket boosters help propel both the orbiter and the external tank during the first two minutes of ascent.

Description

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. It is roughly the size of a McDonnell Douglas DC-9.

Orbital Vehicle

The Orbiter's crew cabin consists of three levels: the flight deck, the mid-deck, and the utility area. The uppermost 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 and 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 mid-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 that mission, the arm has become a crucial part of the thermal protection inspection procedures now required for Shuttle flights. Therefore, it is likely that the Canadarm will be included on all future flights. Three fuel cells are located under the payload bay area. They consume onboard liquid oxygen and liquid hydrogen stores to generate all the electrical power for the vehicle from launch to landing.

The view of the Space Shuttle Atlantis connected to Russia's Mir Space Station was photographed by the Mir-19 crew on July 4, 1995.

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 provide thrust. The aft fuselage also houses three auxiliary power units. The APUs are hydrazine-fueled turbopumps to provide hydraulic pressure for the hydraulic system, which gimbals the three main engines, controls aerosurfaces, and deploys the landing gears.

Two Orbital Maneuvering System (OMS) thusters are mounted in two separate pods in the Orbiter's aft fuselage, located between the SSMEs and the vertical stabilizer of the Orbiter. The OMS engines provide significant thrust for coarse orbital maneuvers, including insertion, circularization, transfer, rendezvous, deorbit, abort to orbit, and abort once around.

The Reaction Control System (RCS) comprises 44 smaller thrusters and provides attitude control and translation along the pitch, roll, and yaw axes during the flight phases of orbit insertion, orbit, and re-entry. The forward RCS jets near the nose of the Orbiter include 12 primary and two vernier RCS engines. The aft RCS engines are located in the OMS pods of the vehicle and include 12 primary and two vernier RCS engines in each pod. The RCS system provides fine control of the Orbiter and is used for the maneuvering during the rendezvous pitch maneuver, docking and undocking with the International Space Station.

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 aluminum alloy, although the engine thrust structure is made from titanium alloy. The windows are made of aluminum silicate glass and fused silica glass, and comprise an internal pressure pane, a three inch thick optical pane, and an external thermal pane. The windows are tinted with the same ink used to make American banknotes.

The shuttle has neither anti-collision, navigation nor landing lights. When landing at night the runway is flooded with light from ground spotlights.

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 lbs (68,586.6 kg)
  • Gross Liftoff Weight: 240,000 lbs (109,000 kg)
  • Maximum Landing Weight: 230,000 lbs (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 nm (185 to 1,000 km)
  • Speed: 25,404 ft/s (7,743 m/s, 27,875 km/h, 17,321 mph)
  • Crossrange: 1,085 nautical miles (2,009.4 km)
  • Crew: 6-7 (Commander, Pilot, 4-5 Mission Specialists and/or Payload Specialists), 2 (Commander and Pilot) for minimum.
  • Crew Compartment Space: 2,325 cu.ft (With internal airlock) or 2,625 cu.ft (With external airlock inside the payload bay)

Fleet

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.

Test Articles
Number Name Notes
OV-095
- Shuttle Avionics Integration Laboratory replica for avionic system testing and training
OV-098 (honorary)
Pathfinder Orbiter Simulator for moving and handling tests
MPTA-098
- Testbed for propulsion and fuel delivery systems
STA-099
- Structural test article used for stress and thermal testing, later became Challenger
OV-101
Enterprise Used for approach and landing tests, not suitable for spaceflight
Orbiters
Number Name Notes
OV-099
Challenger Destroyed after liftoff - January 28, 1986
OV-102
Columbia Destroyed during reentry February 1, 2003
OV-103
Discovery First launched on August 30, 1984
OV-104
Atlantis First launched on October 3, 1985
OV-105
Endeavour First launched on May 7, 1992
Challenger while in service as structural test article STA-099. Adventure on display at Space Center Houston.
  • Enterprise was a prototype designed to test Space Shuttle behavior in atmospheric flight. It is currently on display at the Smithsonian's National Air and Space Museum Steven F. Udvar-Hazy Center at Dulles International Airport.
  • Columbia first launched on April 12, 1981. On February 1, 2003, Columbia disintegrated during re-entry on its 28th mission.
  • Challenger first launched on April 4, 1983. On January 28, 1986 it broke up 73 seconds after the launch of its 10th mission.
  • Discovery first launched on August 30, 1984. It has flown 35 missions and is still operational today. It was NASA's Return to Flight vehicle, following the Challenger and Columbia disasters. It is due to be retired in 2010.
  • Atlantis first launched on October 3, 1985. It has flown 30 missions and is still operational today. It is scheduled to be retired in 2010.
  • Endeavour first launched on May 7, 1992. It has flown 22 missions and is still operational today. It is due to be retired in 2010.

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 Houston
  • Space Shuttle America, a full-scale mockup of the actual space shuttle for a theme park attraction
  • Space Shuttle Pathfinder, a full-scale mockup of the actual space shuttle displayed at Space Camp in Huntsville, Alabama

Flight statistics

Flight statistics
Shuttle Flights Flight days Orbits Longest flight First flight Last flight Mir/ISS
docking
STS Date STS Date
Columbia 28 300d 17h 46m 42s 4,808 17d 15h 53m 18s STS-1 Apr 13, 1981 STS-107 † Jan 16, 2003 0 / 0
Challenger 10 62d 07h 56m 15s 995 08d 05h 23m 33s STS-6 Apr 04, 1983 STS-51-L † Jan 28, 1986 0 / 0
Discovery 36 309d 09h 24m 00s 4,764 15d 02h 24m 02s STS-41-D Aug 30, 1984 STS-119 Mar 15, 2009 1 / 10
Atlantis 30 270d 05h 59m 41s 4,602 13d 20h 12m 44s STS-51-J Oct 03, 1985 STS-125 May 11, 2009 7 / 9
Endeavour 23 266d 15h 47m 08s 4,212 16d 15h 08m 48s STS-49 May 07, 1992 STS-127 Jul 15, 2009 1 / 10
Total 127 1209d 08h 53m 46s 19,381   9 / 29

(As of 10 August 2009)

† No longer in service (destroyed)