On March 2, 1972, NASA launched Pioneer 10, its first space probe to the planet Jupiter. No previous space probe had ever ventured out this far. It carried eleven different scientific instruments. Its mission was to be the first probe to send back detailed data about the Jovian system.
Pioneer 10 lived up to its name by incorporating many historic firsts into the mission. It was the first probe placed on a trajectory to escape the solar system into interstellar space; the first spacecraft to fly beyond Mars; the first to fly through the asteroid belt; the first to fly past Jupiter; and the first to use all-nuclear electrical power radioisotope thermal generators.
On July 15, 1972, Pioneer 10 entered the asteroid belt. This was a crucial time for the mission since there was still a great deal of speculation about what the danger of crossing through the main asteroid belt would be. The probe emerged unharmed in February 1973 after a voyage of about 271 million miles.
By December 1, 1973, Pioneer 10 was returning better images of Jupiter than possible from ground-based telescopes on Earth. The probe’s closest approach was on December 4, 1973, when the spacecraft came within 81,000 miles of Jupiter while travelling past at a velocity of approximately 78,000 miles per hour.
During the mission, the spacecraft took about 500 pictures of Jupiter’s atmosphere with the highest resolution of about 200 miles. In addition to photographing Jupiter, Pioneer 10 also passed by a series of Jovian moons, obtaining photos of Callisto, Ganymede, and Europa.
Pioneer 10 crossed the orbit of Neptune on June 13, 1983. It remained the farthest human-made object in existence until February 17, 1998, when it was passed by the Voyager 1 spacecraft. Pioneer 10 returned its last telemetry data on April 27, 2002, and sent its last signal on January 23, 2003, when it was 7.6 billion miles from Earth. It also carries an aluminum plaque with diagrams of a man and a woman, the solar system, and its location relative to 14 pulsars. This plaque was the precursor to the golden records carried by Voyagers 1 and 2 that were launched in 1977.
The mission was a remarkable success for NASA, proving that a voyage to Jupiter was possible. The exploration of Jupiter continued with Pioneer 11 in 1974, Voyagers 1 and 2 in 1979, Galileo in 1995, and the JUNO probe in 2016. Pioneer 10 is heading in the general direction of the red star Aldebaran, the eye of the bull in the constellation Taurus. The spacecraft is expected to pass by Aldebaran in approximately two million years.