FAQs

What is the cost of a Space Shuttle?

Space Shuttle Endeavour, the replacement orbiter for Space Shuttle Challenger , cost approximately $2.1 billion.

Why send people into space when unmanned spacecraft cost less?

Following the Challenger accident, NASA developed a "mixed fleet" approach to placing payloads in space missions that do not require a human interface, or other types of service available only on board a Space Shuttle orbiter, have been rescheduled for unmanned vehicles. Payloads such as the Synom-type satellites, which were specifically designed to be launched on board Space Shuttles, and payloads such as the Hubble Space Telescope, which require extensive on-orbit checkout before final development, must be flown on the Space Shuttle. Others, such as the Cosmic Background Explorer (COBE) and the Roentgen Satellite (ROSAT), which were originally planned for flights on Space Shuttles, have been successfully launched on unmanned space vehicles.

How much does a spacecraft weigh in space?

A spacecraft in orbit has been said to be in a state of weightlessness -- but the preferred term today is microgravity. Microgravity results from giving a spacecraft enough forward velocity to counter-balance the downward pull of gravity. Another way to look at it is that a spacecraft in a circular orbit is always falling toward Earth, because gravity is pulling on it as it does on all orbiting objects, but its forward speed is high enough to keep the curved surface of the Earth below moving a way, at a rate equal to the amount of fall. The net result -- since there is no air in space to create friction and slow the spacecraft down -- is that the orbiting object stays the same distance above the surface. Everything in or near the spacecraft is also operating in microgravity. A spacecraft on a long voyage between planets is actually in orbit around the sun, where its forward velocity counters the pull of gravity, in the same manner that a satellite orbits the Earth.

What is the Space Shuttle's speed, altitude and amount of fuel used?

Each of the Solid Rocket Boosters on a Space Shuttle contains more than one million pounds of propellant, and the External Tank is loaded with 500,000 gallons of liquid oxygen and liquid hydrogen. A new External Tank is used on each launch, but the Solid Rocket Boosters are refilled with propellant for other Shuttle missions.

How hot or cold does it get in space?

In space around the Earth, including the vicinity of the Moon, objects in direct sunlight can heat up to temperatures of about 250 F (121 C). When shielded from the sun, objects can cool to around -250 F (-156 C). Astronauts in spacesuits, or in the orbiter cabin, work in a steady temperature range of 70-80 F (21-27 C), as long as the thermal control systems are working properly.

How is the Shuttle spacesuit different from the suits used in previous programs?

Early life-support systems were cumbersome, and the astronaut's ability to move in them somewhat restricted. The Shuttle spacesuit is far less bulky and much more comfortable. It is also more versatile and easier to manage. In the Mercury, Gemini and Apollo programs, a suit was custom tailored to fit each astronaut. Shuttle spacesuits come in standard pieces in several sizes, which can be combined to fit either male or female crew members. These pieces can be repaired and reused over a number of years, making it much less expensive to outfit an astronaut today than in the past.

What is a launch window?

The precise period of time in which a given lift-off must occur is called the launch window. For example, a preset launch time is required when the Space Shuttle orbiter must rendezvous with another object already in orbit, as the orbiter. Columbia did in January 1990, when it retrieved and returned the Long Duration Exposure Facility to Earth. Sometimes an orbiter must be in a specific position at a certain time in order to deploy a spacecraft on a planetary trajectory, as Atlantis did on separate missions when it sent the Galileo spacecraft towards Jupiter and the Magellan spacecraft towards Venus.

What are the names of the Space Shuttle orbiters?

The names, in the order they were built, are Enterprise, Columbia , Challenger, Discovery, Atlantis and Endeavour. The Enterprise was flown only in approach and landing tests, and was never intended for space flight. Columbia completed the first five Space Shuttle missions. Challenger was originally built as a vibration test vehicle, then later upgraded to become the second operational orbiter. The Challenger and her crew were lost in an accident on January 28, 1986. Discovery made its first flight in August 1984, and Atlantis in October 1985. Endeavour, built to replace the Challenger, made its debut in May 1992.

Can the Space Shuttle be used to dispose of hazardous wastes?

No. The Space Shuttle is designed for scientific missions in the fields of space research, exploration and technical and scientific applications.

What happens to used spacecraft? Where is the first Space Shuttle orbiter, Enterprise ?

In earlier manned space flight programs -- Mercury, Gemini and Apollo -- spacecraft which returned to Earth underwent post-flight checkouts that yielded valuable additional information on their performance and on the effects of traveling in space. Most then went on public display. They can be seen at the National Air and Space Museum of the Smithsonian Institution in Washington, DC and other major museums. The first Space Shuttle orbiter, Enterprise, was never intended for space flight. It was used for fit checking, mechanical and electrical compatibility checks and flight worthiness tests (it was dropped from the back of its transport aircraft four times, to glide back to Earth). It was then flown for display over the United States, Canada and Europe before being turned over to the Air and Space Museum

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