Vehicles

Space vehicles encompass different categories of spacecraft, including satellites,rockets, space capsules,space stations, and colonies. In general, satellites are considered any object launched by a rocket for the purpose of orbiting Earth or another celestial body. A rocket, on the other hand, is a vehicle or device, especially designed to travel through space, propelled by one or more engines.

A Brief History of Space Vehicles

The Soviet Union launched the first successful satellite, Sputnik 1 in October 1957. America's first satellite, Explorer 1, followed Sputnik by three months, in January 1958. Soon after satellites orbited the Earth, space capsules were launched containing closed compartments designed to hold and protect humans and/or equipment. Less than three years after Sputnik 1, both the United States and Soviet Union put capsules into space with humans aboard. In 1961 cosmonaut Yuri Gagarin became the first person in space aboard a Vostok space capsule. A month later, American astronaut Alan Shepard in the Mercury capsule Freedom 7 made a 14.8-minute sub-orbital flight, becoming the first U.S. astronaut in space.

While the American space program focused first on the Apollo missions to the Moon and then turned to development of the space shuttle (the first reusable launch vehicle) and low Earth orbit operations, the Soviet Union established a series of space stations in Earth orbit. Space stations are large spacecraft equipped to support a crew and remain in orbit for an extended period of time to serve as a base for launching exploratory expeditions, conducting scientific research, repairing satellites, and performing other space-related activities. The Soviets' first space station, Salyut 1, was launched in 1971. Later, the Soviet Union and Russia orbited the Mir space station. America's first space station, and the only one that it deployed during the first four decades of human spaceflight, was the 100-ton Skylab launched in 1973. Today, the United States, Russia and other international partners are constructing the International Space Station, Alpha.

The Future of Space Vehicles

A major imperative for the future is to reduce the cost of getting to orbit. To this end significant funds have already been invested in technology development towards a single-stage-to-orbit reusable space vehicle to replace the shuttle. Problems with the X-33 scaled prototype led to a recognition that development of such a vehicle is still years away. The U.S. government has committed to a series of shuttle upgrades to keep the fleet flying and to improve safety and capability. A likely intermediate stage is development of a two-stage-to-orbit reusable vehicle, possibly building on shuttle components with fly-back boosters. (The shuttle discards its solid rocket boosters minutes after launch. The casings are reclaimed from the sea and towed back to land to be reused. A booster that could fly back to the space center runway on automatic pilot after fulfilling its role in boosting the spacecraft launch would be a significant advance.)

Looking to the far horizon, space elevators, launch systems driven by a massive catapult system (the so-called slingatron), or sophisticated magnets, could revolutionize the way payloads are launched to space. New forms of nuclear propulsion, plasma propulsion,antimatter systems, vastly improved solar sail techniques, faster-than-light travel, or the exploitation of zero point energy for transportation through space could move humankind into a new space age that leaves traditional chemical propulsion behind.

The establishment of permanent space colonies has fascinated people for decades. Permanent settlements have been proposed for the Moon and Mars, as well as stable positions in space equidistant from both Earth and Moon called the Lagrangian libration points. Space visionaries advocated a space colony at L5 early in the space age. More recently NASA scientists have considered placing a space station at L2. In the future, space transportation vehicles serving humans and space habitats will become more spacious and more conducive to long journeys or permanent habitation. Eventually, space settlers, like the immigrants who came to America, might consider their settlement "home" and become increasingly self-sufficient by growing their own food and using solar energy to generate electricity and manufacture goods.

SEE ALSO CAPSULES (VOLUME 3); GETTING TO SPACE CHEAPLY (VOLUME 1); LAUNCH VEHICLES, EXPENDABLE (VOLUME 1); LUNAR BASES (VOLUME 4); MARS BASES (VOLUME 4); REUSABLE LAUNCH VEHICLES (VOLUME 4); SATELLITES, TYPES OF (VOLUME 4); SETTLEMENTS (VOLUME 4); SPACE ELEVATORS (VOLUME 4); SPACE SHUTTLE (VOLUME 3); SPACE STATIONS OF THE FUTURE (VOLUME 4)

Pat Dasch and John F. Kross

Bibliography

Hacker, Barton C., and James M. Grimwood. On the Shoulders of Titans: A History of Project Gemini. Washington, DC: NASA Historical Series (NASA SP-4203), 1977.

Lewis, Richard S. Appointment on the Moon. New York: The Viking Press, 1968.

Millis, Marc G. "Breaking through to the Stars."Ad Astra 9, no. 1 (January-February1997):36-41.

Puthoff, H. E. "Space Propulsion: Can Empty Space Itself Provide a Solution?"Ad Astra 9, no. 1 (January-February 1977):42-46.

Yenne, Bill. The Encyclopedia of US Spacecraft. New York: Exeter Books, 1988.

Internet Resources

Colonization of Space. NASA Ames Research Center.<http://lifesci3.arc.nasa.gov/SpaceSettlement/75SummerStudy/Table_of_Contents1.html>.