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Space exploration
Types of shuttle missions


columbia shuttle

Types of
shuttle missions

Space shuttles carry artificial satellites, space probes, and other heavy loads into orbit around Earth. In addition to launch operations, the shuttles can retrieve artificial satellites that need servicing. Astronauts aboard the shuttle can repair the satellites and then return them to orbit. Shuttle crews can also conduct many kinds of scientific experiments and observations.

Commercial satellite launches. The first launch of a payload for a customer took place in November 1982. The shuttle Columbia launched two communications satellites. Solid-rocket boosters helped the satellites climb to their designated orbits. Many later satellite launches followed. NASA discovered that using the space shuttle to launch satellites was more flexible than it had expected. However, the length of time required to ready each space shuttle for its next launch was also greater than NASA planners had expected and sometimes caused expensive delays.

Military missions. About one-fourth of the shuttle missions during the 1980's were conducted for military purposes. Astronauts on these missions sent special observation satellites into orbit and tested various military instruments. To prevent the discovery of information about the capabilities of these satellites, unusual secrecy surrounded the missions. NASA did not reveal launch times of the missions in advance or release any conversations between mission control and the astronauts in space. In the early 1990's, the United States phased out the use of shuttles for such missions and resumed the use of cheaper, single-use rockets.

Repair missions.
The space shuttle enables astronauts to retrieve, repair, and relaunch broken satellites. This important capability was first demonstrated in April 1984, when two astronauts from the shuttle Challenger repaired the Solar Maximum Mission satellite-the only solar observatory in orbit. This success underscored the flexibility and capability of human beings in space. Since then, astronauts have repaired several other satellites in space.

In 1993, a crew from the shuttle Endeavour repaired the orbiting Hubble Space Telescope. After the telescope had been launched in 1990, NASA engineers discovered an error in its primary mirror. The Endeavour astronauts installed optical equipment that cancelled out the effect of the error. The crew also replaced certain scientific instruments, the solar panels, and the gyroscopes, devices used in pointing the telescope.

Spacelab missions. Spacelab was a facility that enabled shuttle crews to perform a wide variety of scientific experiments in space. It was built as a part of the space shuttle program by the European Space Agency. The first Spacelab mission was launched in 1983 in the space shuttle Columbia. In 1998, the same shuttle carried Spacelab on its last mission. Each mission focused on research in a particular area of science or technology, such as astronomy, the life sciences, and microgravity.

Spacelab consisted of a piloted space laboratory and several separate platforms called pallets. The pressurized laboratory was connected to the crew compartment by a tunnel. It had facilities for scientists to conduct experiments in manufacturing, medicine, the production of biological materials, and other areas. The pallets carried large scientific instruments that were used to conduct experiments in astronomy and other fields. Scientists operated the instruments from the laboratory, from the shuttle's orbiter, or from the ground. Spacelab facilities were shared by the ESA and the United States.

Contributor: James Oberg, M.S., Spaceflight Engineer; author, UFOs and Outer Space Mysteries.
Source : World Book 2005

Space exploration
What is space?
Getting into space and back
Living in space
Meeting basic needs in space
Communicating with Earth
The dawn of the space age
Space probes
Probes to Venus
Probes to Jupiter and beyond
Probes to comets
Human beings enter space
Apollo: Mission to the moon
Exploring the moon
Returning to Earth
The International Space Station
Space shuttles
Types of shuttle missions