Pioneer 10
Pioneer 10 is a NASA space probe launched in 1972 that completed the first mission to the planet Jupiter. Pioneer 10 became the first of five artificial objects to achieve the escape velocity needed to leave the Solar System. This space exploration project was conducted by the NASA Ames Research Center in California. Between July 15, 1972, and February 15, 1973, it became the first spacecraft to traverse the asteroid belt. Radio communications were lost with Pioneer 10 on January 23, 2003, because of the loss of electric power for its radio transmitter, with the probe at a distance of 12 billion kilometers from Earth.
Pioneer 11
Pioneer 11 (also known as Pioneer G) is a NASA robotic space probe launched on April 5, 1973, to study the asteroid belt, the environment around Jupiter and Saturn, solar winds, and cosmic rays. It was the first probe to encounter Saturn, the second to fly through the asteroid belt, and the second to fly by Jupiter. Later, Pioneer 11 became the second of five artificial objects to achieve an escape velocity allowing it to leave the Solar System. Due to power constraints and the vast distance to the probe, the last routine contact with the spacecraft was on September 30, 1995, and the last good engineering data was received on November 24, 1995.