An interplanetary mission is a voyage or trip through space involving more than one planet. This is an important distinction because it requires significantly more ΔV (change in velocity) than do missions within a single planetary system.
As of 1973, there have been no manned interplanetary missions, although the Apollo Applications Program planned a three month interplanetary mission to Venus using Apollo hardware in the 1970s. So far, all manned missions have been within the Earth's planetary system (i.e. to the moon or closer). The American space agency NASA intends to be able to launch a manned interplanetary mission to Mars by some time after 2015 under the Vision for Space Exploration. The European Space Agency has the long-term vision of sending a human mission to Mars by 2030 under the Aurora Programme.
A large number of robotic interplanetary missions have been performed by the USA, the Soviet Union (and later by Russia), Japan and the European Union.
The first interplanetary mission to fly past another planet was the Soviet Union's Venera 1. The robotic spacecraft was intended to enter into orbit around Venus, but suffered a malfunction and radio contact with the spacecraft was lost. The defunct Venera 1 passed within 100,000 km (62,000 mi) of Venus before entering a heliocentric orbit. The United States' Mariner 2 became the first successful interplanetary mission in December 1962 when it collected data within 35,000 km (22,000 mi) of Venus.
The Soviet Union's Venera 3 crashlanded on Venus in March 1966 without returning any data on the planet, although technically becoming the first manmade object to land on another planet. In October 1967, the Soviet Union's Venera 4 became the first successful interplanetary mission to land on another planet.
The United States' Mariner 10 became the first successful interplanetary mission to visit more than one planet outside Earth's planetary system. Mariner 10 flew by Venus once, in February 1974, and flew by Mercury three times, in March and September 1974, and March 1975.
There are currently five spacecraft on trajectories which either will or have already taken them out of the solar system, depending on the definition used to determine the solar system's boundary. These probes are Voyager 1, Voyager 2, Pioneer 10, Pioneer 11 and New Horizons, all launched by the United States.
See also:
- Timeline of planetary exploration.
- NASA Exploration Systems Mission Directorate
Famous quotes containing the word mission:
“... [a] girl one day flared out and told the principal “the only mission opening before a girl in his school was to marry one of those candidates [for the ministry].” He said he didn’t know but it was. And when at last that same girl announced her desire and intention to go to college it was received with about the same incredulity and dismay as if a brass button on one of those candidate’s coats had propounded a new method for squaring the circle or trisecting the arc.”
—Anna Julia Cooper (1859–1964)