Hobbies And Interests
Early Satelites
The Soviet Union's 10 Sputnik spacecraft of the late '50s helped scientists understand the rigors of space travel. Some, such as Sputnik 2, carried animals such as dogs to learn the effects of space travel on living things. Launched by the United States between 1958 and 1975, the Explorer spacecraft discovered the innermost of the radioactive Van Allen belts circling Earth, measured deep space radio signals and took the first pictures of Earth from space. Launched by the United States between 1958 and 1959, the three "Vanguard" satellites discovered that Earth is slightly pear-shaped and mapped the planet's magnetic field.
Moon
Between 1959 and 1976, the Soviet Union launched 24 spacecraft in the Luna series toward the moon. The series had several firsts, including the first craft to land on the moon, the first to send back pictures of the moon's far side, the first craft to return lunar samples to Earth and the first exploration vehicle on the moon. Launched between 1961 and 1965, Project Ranger was the first American attempt at lunar exploration. Ranger 4 was the first American craft to reach the lunar surface, while Ranger 7 through Ranger 9 sent back more than 17,000 photos of the lunar surface.
Inner Planets
Launched between 1958 and 1978, the Pioneer spacecraft were the first American craft designed for interplanetary travel. The first five explored space near the moon, Pioneer 6 studied the region between Earth and Venus, and Pioneer 12 and Pioneer 13 studied Venus. Launched by the Soviet Union between 1961 and 1984, the Venera spacecraft explored Venus. Venera 3 was the first spacecraft to reach the surface of another planet, while Venera 4 through 6 sent back important data about Venus' atmosphere.
Launched by the United States in 1975, the two Viking spacecraft surveyed the surface of Mars before launching landing craft that probed the planet's surface. Launched by the U.S. in 1996, the Mars Global Surveyor sent back more data about Mars than all previous Mars missions combined and helped debunk the infamous "face on Mars" myth.
Outer Planets
In 1973, Pioneer 10 became the first spacecraft to fly past Jupiter. It was followed by Pioneer 11, which passed Jupiter in 1974 and Saturn in 1979. Both carried friendship messages on gold plaques in case of encounters with extraterrestrials. Launched by the U.S. in 1977, Voyager 1 and Voyager 2 explored Jupiter, Saturn, Neptune and Uranus. They sent back detailed photos of the planets and their moons and collected data on their rings and magnetic fields. Launched by the U.S. in 1989, Galileo explored Venus, the asteroids Gaspra and Ida and Jupiter. Launched in 1997 by the United States and the European Space Agency, Cassini explored Saturn and sent a landing craft to Saturn's moon Titan.