Space Shuttle

"How many more years I shall be able to work on the problem I do not know; I hope, as long as I live. There can be no thought of finishing, for 'aiming at the stars' both literally and figuratively, is a problem to occupy generations, so that no matter how much progress one makes, there is always the thrill of just beginning."

- Robert H. Goddard

Shuttle Mission Statistics

Next Space Shuttle Mission:
STS-128 International Space Station Flight 17A

Orbiter:
OV-103 Discovery

Mission Number:
128^th Space Shuttle Flight

Launch:
August 28, 2009 @ 12:22 A.M. EDT

Launch Window:
10 Minutes

Launch site:
KSC Launch Pad 39A

Inclination:
51.6 Degrees

Altitude:
122 Nautical Miles

Duration:
13 Days

Landing:
KSC Shuttle Landing Facility @ TBD

Crew:
Commander Frederick W. "Rick" Sturckow
Pilot Kevin A. Ford
Mission Specialist Patrick G. Forrester
Mission Specialist Jose M. Hernandez
Mission Specialist Christer Fuglesang
Mission Specialist John D. "Danny" Olivas
Mission Specialist/ISS Flight Engineer Nicole P. Scott
Mission Specialist/ISS Flight Engineer Timothy L. Kopra

Payload:
Leonardo Multi-Purpose Logistics Module
Lightweight Multi-Purpose Experiment Support Structure Carrier
COLBERT treadmill

Specifications

Information

Shuttle History

The shuttle program came about due to the intensive aeronautical researching during the period of the 1950's and the 1960's, which focused on the development of winged rocket planes that could return back to Earth. These vehicles had many advantages compared to the vintage capsule spacecraft: they could land on ordinary runways, were cheaper then all the necessary equipment and other requirements that were needed to stage a successful splashdown landing at sea, and were reusable. NASA started the reusable space shuttle program while the Apollo program was underway, but it had not officially started until 1972 when Richard Nixon signed an executive order to start the Space Transportation System (STS). By the 1960s, NASA decided that if space flight was going to be as routine as hoped for, then the next generation of spacecraft would have to be reusable to reduce overall cost. Rockwell was awarded the contract for the shuttle's design and the same year that the program started, construction soon followed. NASA's original vision was for a fleet of a dozen or so such space shuttles to routinely fly into space once or twice a week. The goal was to take people to and from a space station that would become operation in the later half of the 1970s. The space shuttles were designed to take-off like a rocket and land like an airplane, and each orbiter was designed to fly up to 100 sorties. It was not at all easy for the shuttle designers, they had to design a flexible yet reliable system of computer control, needed to develop a special heat shield for re-entry, and they needed to make the shuttle main engines reusable for many missions. In 1977, NASA used the first space shuttle, Enterprise, to conduct approach and landing tests aboard a modified 747 jumbo jet. The 747 carried the shuttle up and brought it back on several flights leading up to the eventual release of the Enterprise from the 747. On April 12, 1981 the first shuttle, Columbia, launched and conducted the first orbital mission with John W. Young and Robert L. Crippen at her controls. Two days later, Columbia came to an airplane-like landing at Edwards Air Force Base (AFB). The shuttle program was first utilized to launch military and commercial satellites. However after the Challenger accident, which drastically shook up the shuttle program, the shuttle was decided to be only used to carry out repair missions, joint cooperation missions, construct of the ISS, scientific research, and many other activates. After the Space Shuttle Columbia disintegrated upon re-entry in early 2003, the shuttle program was decided to be used only to service and construct the ISS.
 

A True Aerospace Vehicle

The space shuttles are true aerospace vehicles. They leave earth and its atmosphere under rocket power provided by three liquid-fueled main engines, referred to as Space Shuttle Main Engines (SSMEs), and two solid-fuel rocket boosters (SRBs) attached to an external liquid fuel tank. After their missions in orbit cease, the shuttles streak back through the atmosphere and are maneuvered to land much like an airplane. The shuttles, however, are without engine power and land more like gliders than typical aircraft. Other types of rockets can place heavy payloads into space, but they are used only once, thus giving them the distinction of being known as expendable launch vehicles. Space shuttles are designed to be used 100 times allowing them to earn the honor of being reusable.

Space shuttles were used and designed to transport complete scientific laboratories into space. The laboratories remain inside the payload bay throughout the mission. They are removed after the orbiter returns to earth and can be prepared for another shuttle flight. Some of these laboratories, like the Spacelab developed by the European Space Agency (ESA), provide facilities for several specialists to conduct experiments in such fields of science as medicine, astronomy, and materials manufacturing.

Among the types of satellites the shuttle can orbit and service in space are those involved in environmental and resources protection, weather forecasting, navigation, oceanographic studies, and other fields useful to citizens throughout the world. Interplanetary spacecraft can be placed into orbit by space shuttles with the use of a propulsion unit called the Inertial Upper Stage (IUS). After the satellite or spacecraft is deployed from the shuttle payload bay, the IUS is ignited to accelerate the spacecraft into its proper orbit and away from the gravitation influences of Earth.

Presently, space shuttles are being used to carry into orbit the structural components that comprise the International Space Station, a permanent scientific facility in which crews of astronauts work for extended periods of time in space. The shuttles also have the capabilities of assembling various components of the station using the Remote Manipulator System (RMS). The space station has its own solar power units that allow the astronauts to carry out a wide range of scientific activities. Space shuttles are not only used to help construct the space station, but are often used a high tech ferries to transfer crew and supplies between the ISS and Earth.

Development History

In 1969, shortly after the first moon landing of the Apollo program, the President's Space Task Group recommended that the United States initiate a program to develop a new space transportation system. In 1970 NASA initiated engineering, design, and cost studies dealing with the concept of a reusable manned spacecraft that utilized strap-on solid propellant rockets and an expendable liquid fuel/oxidizer tank.

On January  5, 1972, President Richard M. Nixon gave NASA the authority to proceed with full development of this type of reusable space system. NASA selected the Space Transportation Systems (STS) Division of Rockwell International, Downey, Calif., to build the orbiters. Rockwell's Rocketdyne Division builds the three main engines used on each orbiter. Morton Thiokol, Brigham City, Utah, manufactures the solid rocket booster motors, and Martin Marietta Corp., New Orleans, La., makes the external fuel tank.

A Typical Shuttle Mission

Space shuttles are launched from the National Aeronautics and Space Administration's (NASA) John F. Kennedy Space Center (KSC) located in Cape Canaveral, Florida.

The orbiter processing area is several miles from the launch pads. After the orbiter vehicles (OV) are readied for flight they are moved from the Orbiter Processing Facility (OPF) to the Vehicle Assembly Building (VAB). Here the vehicle is mated with the external fuel tank (ET) and the solid rocket boosters (SRBs) and then the assembled components receive final detailed systems checks before they are moved out of the VAB to the launch pad.

The orbiter's main engines and the booster rockets ignite simultaneously to lift the shuttle and its crew away from earth and into space. About two minutes after launch, the solid rocket boosters complete their firing sequence and separate from the external tank and, by parachute, fall back into the ocean where they are recovered and used again. The orbiter continues its flight into space with the main engines furnishing ascent power for another six minutes before they are shut down, just before achieving orbit. The external tank, now empty, separates and falls back into the atmosphere and breaks up over a remote area of the ocean. It will never be used again.

In orbit, space shuttles circle the earth at a speed of about 17,500 mph. Each orbit is about 90 minutes in duration and the crew will view a sunrise or a sunset every 45 minutes.

Orbital altitudes for shuttle missions range from as low as 155 miles to as high as 600 miles, based on mission requirements. The flight paths are within a region over earth extending from 57 degrees north to 57 degrees south of the equator.

Missions usually last up to 10 days, but the crew has food, fuel, and other supplies to remain in orbit several days longer than planned in case they cannot come back on time due to bad weather at the landing sites or other types of unforeseen circumstances..

The crew size varies and can be as large as eight people, although up to 10 can be carried under special conditions. The crew includes the commander, the pilot, and enough mission specialists and payload specialists to carry out the specific mission. Mission specialists are responsible for equipment and resources supporting the payloads during the flight, while the payload specialists are in charge of the specific payload equipment. The mission commander, pilot, and mission specialists are NASA astronauts and assigned by administration. Payload specialists may or may not be astronauts, and are nominated for the mission by the payload sponsor.

When the mission ends and the orbiter begins to glide back through the atmosphere, special insulation covering the outside portions of the vehicle act as a heat shield to keep it from getting too hot from air friction and damage due to the the tremendous heat. Most of the insulation used to protect the orbiter in places where it gets extremely hot is shaped like small tiles. The tiles, about six inches square and made of silica, shed heat so well that one side is cool enough to hold in bare hands while the other side is red hot and withstands temperatures of 2300 degrees (F). Some tiles get damaged during launch or landing and will need to be replaced during orbiter processing.

After the space shuttles began flights in April 1981 Edwards Air Force Base, California, the location of NASA's Dryden Flight Research Center, was the primary landing site. The shuttles used the main 15,000-foot runway, or on Rogers Dry Lake, which has seven designated runways on the natural clay surface. The Kennedy Space Center is now the primary landing site, with Edwards remaining as an alternate. When certain developmental tests on orbiter systems are being carried out, Edwards is an excellent landing site because of the safety margin presented by the lakebed and the number of runways from which mission controllers and shuttle crews can choose.

The landing speed of the orbiters ranges from 205 to 235 mph, based on the weight of the vehicle. Among improvements to the orbiters since flights began have been installation of a drag parachute at the aft end of the fuselage. They are deployed when the orbiters land to help reduce rollout speed to reduce tire and brake wear. Endeavour, the newest orbiter, was the first to have the drag chute system installed. They have been retrofitted on the other vehicles.

Post-Landing Operations

As soon as the landing occurs, a team of space shuttle recovery operations specialists carefully inspect the orbiter to be sure no gases or fuels are present that may present a toxic hazard. This clears the way for the shuttle crew to power down the vehicle while other ground operations personnel begin connecting up ground support equipment and prepare to tow the spacecraft from the landing site to the space shuttle deservicing area at either the Kennedy Space Center in Florida or at Dryden.

Hoses from two large mobile units are attached to the orbiter during the towback from the landing site. One is a large air conditioning unit to direct cool air into the orbiter's aft fuselage, payload bay, wings, vertical stabilizer, and orbital maneuvering-reaction control system pods to dissipate heat generated by atmospheric reentry. The other unit is a Freon coolant system to protect the flight crew area and avionics systems from excessive heat during post-landing systems checks.

When the orbiters land at Dryden, they are towed to the Mate-Demate Device (MDD). It is a large gantry-like structure where the orbiters receive post-flight servicing and are prepared for a piggy back flight to the Kennedy Space Center riding on top of the NASA 747 Shuttle Carrier Aircraft (SCA). Before the ferry flights begin, all orbiter systems are checked thoroughly and certain fuel lines and tanks are purged.

Post-flight servicing and ferry flight preparations at the MDD normally take about five days. When the orbiter is ready for the ferry flight, it is lifted by the MDD and placed on special mounts atop the SCA fuselage. Transfer flights back to the Kennedy Space Center usually take one to two days, based on weather along the route.

Component Descriptions

The space shuttle system is composed of several large components: the orbiter vehicle (OV), the space shuttle main engines (SSME), the external tank (ET), and the solid rocket boosters (SRBs). The gross launch weight is about 4.5 million pounds, however, this number varies based on payload weight and consumable supplies.

Orbiter: Each orbiter is 121 feet long, has a wingspan of 78 feet, and a height of 57 feet. It is comparable in size to a DC-9 commercial airliner, and can carry a payload of 65,000 pounds into space. The payload bay is 60 feet long and 15 feet in diameter. The landing weight will vary from mission to mission and ranges from 200,000 pounds to 230,000 pounds. Most of its basic construction, like an aircraft, is of aluminum. The forward fuselage houses the cockpit and crew cabin and crew work areas. The mid-fuselage area consists of the payload bay, and the wing and main landing gear attachment points. The aft fuselage houses the main engines, the orbital maneuvering system (OMS), the reaction control system (RCS) pods, the wing aft spar, and the attachment point for the vertical tail. Each orbiter is designed with a lifetime of about 100 space missions.

Main Engines: Each main engine, operating on a mixture of liquid oxygen and liquid hydrogen, produces a sea level thrust of 375,000 pounds and a vacuum thrust of 470,000 pounds. They can be throttled over a thrust range of 65 to 109 percent, allowing a high power setting during liftoff and initial ascent, but a power reduction to limit acceleration of the orbiter to 3Gs during final ascent. The engines are gimbaled (movable) to provide pitch, yaw, and roll control during the ascent phases of flight. Normal engine operating time on each flight is about 8.5 minutes. Each engine has a designed lifetime of about 7.5 operating hours.

External Tank: Each external tank is 154 feet long and 28.6 feet in diameter. They are constructed primarily of aluminum alloys. Empty weight of an external tank is approximately 78,100 pounds. When filled and flight ready, each has a gross weight of 1,667,677 pounds and contains nearly 1.6 million pounds (143,060 gallons) of liquid oxygen and more than 226,000 pounds (526,126 gallons) of liquid hydrogen. The external tank is the only major part of the space shuttle system not reused after each flight.

Solid Rocket Boosters: The space shuttle solid rocket boosters are the largest solid propellant motors ever built and the first to be used on a manned spacecraft. Each motor is made of 11 individual wield-free steel segments joined together with high-strength steel pins. Each assembled motor is 116 feet long, 12 feet in diameter, and contains more than l million pounds of solid propellant. The propellant burns at a temperature of 5,800 degrees (F) and generates a lift-off thrust of 2.65 million pounds. The exhaust nozzles are gimbaled to provide yaw, pitch, and roll control to help steer the orbiter on its ascent path. The solid propellant is composed of atomized aluminum powder (fuel), ammonium perchlorate (oxidizer), iron oxide powder (catalyst), plus a binder and curing agent. The boosters burn for roughly two minutes along with the main engines during initial ascent and give the added thrust needed to achieve orbital altitude. After two minutes of flight, at an altitude of about 24 miles, the booster casings separate from the external tank. They descend by parachute into the Atlantic Ocean where they are recovered by ship, returned to land, and refurbished for reuse on a future shuttle flight.

Major Subsystems

Orbital Maneuvering System (OMS): Two rocket units situated at the orbiter's aft end, at the base of the vertical tail, are used to place the vehicle onto its final orbital trajectory and are used for extended maneuvering while in space. The OMS is also used to slow the vehicle's speed in orbit at the end of the mission. When the orbiter slows down, gravity begins pulling it back into the atmosphere and it glides back to earth for a runway landing. The OMS uses nitrogen tetroxide and monomethyl hydrazine for fuel. Each engine produces 6,000 pounds of thrust.

Reaction Control System (RCS): This system consists of 44 nozzles on both sides of the nose and each side of the aft fuselage pod near each OMS engine. The RCS is used throughout the mission to move or roll the orbiter as the crew carries out tasks which require the vehicle to be pointed in certain orientations for experiments or photography. The RCS uses the same types of fuel as the OMS. Thirty-eight of the thrusters produce 870 pounds of thrust each. The six others each produce 25 pounds of thrust.

Electrical Power: Three fuel cells,  supply electrical power on the orbiter during all phases of a mission. The units are located in the mid-body area of the payload bay. Electrical power is produced by the chemical reaction of hydrogen and oxygen, which are supplied continuously as needed to meet output requirements. A by-product of this reaction is drinking water used by the crew. Each fuel cell is connected to one of three independent electrical distribution systems. During peak and average power loads, all three systems are used. During minimum loads, only two are used and the third is on standby, but can be brought back on line instantly if needed. The system provides up to 24 kilowatts of power, ranging from 27.5 to 32.5 volts of direct current (DC).

Hydraulic Power: Three auxiliary power units (APU) furnish power to operate hydraulic systems on the orbiters such as the main engine gimbaling controls, the nose and main landing gear and brake systems, and the rudder, speed brake, and elevator flight control surfaces. The APUs are fueled by hydrazine which is changed into a hot gas by a granular catalyst. The momentum of the expanding gas spins turbine blades and this energy is transferred to gearboxes on the hydraulic pump units. All three APUs operate during launch, but only two are needed for reentry and landing.

Environment Control and Life Support System: The orbiter's environmental control and life-support system purifies the cabin air, adds fresh oxygen, keeps the cabin pressure at standard sea level conditions, heats and cools the air, and provides drinking and wash water. The system also includes lavatory facilities. The cabin is pressurized to sea level (14.7 psi) with 21 percent oxygen and 79 percent nitrogen, comparable to earth's atmosphere. The air is circulated through lithium hydroxide/charcoal canisters which remove carbon dioxide. The canisters are changed on a regular basis. Heat from the cabin and flight-deck electronics is collected by a circulating coolant water system and transferred to radiator panels on the payload bay doors where it is dissipated. The fuel cells produce about seven pounds of water each hour. It is stored in tanks, and the excess water is dumped overboard when the tanks are full. The lavatory unit collects and processes body waste, and also collects wash water from the personal hygiene station. The lavatory unit, located in the mid deck area, operates much like those on commercial airlines but is designed for a weightless space environment.

Thermal Protection: The thermal protection system is designed to limit the temperature of the orbiter's aluminum and graphite epoxy structures to about 350 degrees (F) during reentry. There are four types of materials used to protect the orbiter. Reinforced carbon-carbon is a composite of a layer of graphite cloth contained in a carbon matrix. It is used on the nose cap and wing leading edges where temperatures exceed 2,300 degrees (F). High-temperature reusable surface insulation consists of about 20,000 tiles located mainly on the lower surfaces of the vehicle. They are roughly equivalent to a six inch square and made of a low-density silica fiber insulator bonded to the surface in areas where temperatures reach up to 1,300 degrees (F). Low-temperature reusable surface insulation also consists of tiles. There are about 7,000 of this variety of tiling on the upper wing and fuselage sides where temperatures range from 700 to 1,200 degrees (F) during reentry. Flexible reusable surface insulation (coated Nomex felt) is sheet-type material applied directly to the payload bay doors, sides of the fuselage and upper wing areas where heat does not exceed 700 degrees (F).

** Information provided by NASA Dryden Research Center. **