Pioneer 10 launched 1972

Taking advantage of a rare alignment of the outer planets, NASA launched Pioneer 10 March 2, 1972.  NASA started preparing for the mission in 1964 and created two spacecraft, Pioneer F and Pioneer G.  Later they were renamed Pioneer 10 and Pioneer 11.

On November 8, 1973, Pioneer 10 crossed the orbit of Sinope, an outer moon of Jupiter and made its closest approach to the planet December 3.  The electron radiation around Jupiter caused false commands to be made but many were corrected by contingency commands.  An image of Io and some close-up pictures of Jupiter were lost but the spacecraft obtained pictures of Ganymede and Europa.

On its way out of the solar system, Pioneer 10 crossed the orbit of Saturn in 1976, the orbit of Uranus in 1979, and the orbit of Neptune in 1983.  It is the first spacecraft to leave the solar system.

The mission officially ended March 31, 1997 but the Deep Space Network kept track of its signal until January 23, 2003 when Pioneer 10 sent its last signal.

Pioneer 10 flyby Jupiter 1973

Pioneer 10, launched March 2, 1972, made its closest approach to Jupiter December 4, 1973.  It was the first spacecraft to travel through the asteroid belt and encounter the biggest planet in our solar system. Pioneer 10 passed within 81,000 miles of the cloud tops of Jupiter.  It took measurements of Jupiter's magnetosphere, radiation belts, magnetic field and atmosphere.  These measurements helped in the design of the Voyager and Galileo spacecraft.

Pioneer 11 encounters Saturn 1979

Launched April 6, 1973, Pioneer 11 became the first space probe to encounter Saturn on September 1, 1979.  It followed Pioneer 10 through the asteroid belt and past Jupiter, but then headed toward Saturn.  During its flyby, it discovered a new ring and almost collided with a new moon discovered the day before, Epimetheus.  After the Voyager flybys, it was discovered that Janus (already known moon) and Epimetheus occupy the same orbit and are about the same size, so it could have been either one.

On September 29, 1995, NASA announced it was closing the project after over 22 years.

Pioneer 10 sends its last signal 2003

Fourteen years ago, January 23, 2003, Pioneer 10 sent its last signal received by Earth.  Launched March 3, 1972, Pioneer 10 was the first spacecraft to travel through the asteroid belt and the first to encounter Jupiter, up close and personal, reaching the gas giant December 3, 1973.

It continued broadcasting at a whopping rate of 256 bits/second, which degraded to 127 millibits/second.  When it was approximately 12 billion light-years (80 astronomical units) from Earth, its power fell below the level where it could send signals strong enough to be received.  Now it is estimated to be 116 AU from Earth.

Pioneer 10 Passes Pluto 1983

Way back on June 13, 1983, when Pluto was still a PLANET, Pioneer 10 passed its orbit and entered interstellar space.  Of course, if Pluto had been demoted to a dwarf planet at the time, Pioneer 10 would've entered "interstellar space" years before.

Pioneer 10 carries a gold disc designed by Carl Sagan, which contains depictions of a human male and human female.  It also has diagrams to pinpoint Earth's location in the galaxy, in a solar system with NINE planets.

We've put it out there, people.  We told the entire Milky Way we have nine planets in our solar system!

Pioneer 10's last signal was received January 22, 2003, when it was about 12 billion kilometers from Earth.