Pioneer 10 was launched on 2 March 1972 on top of an Atlas/Centaur/TE364-4
launch vehicle. The launch marked the first use of the Atlas-Centaur as a
three-stage launch vehicle. The third stage was ... required to rocket Pioneer 10
to the speed of 51,810 kilometers per hour (32,400 mph) needed for the flight
to Jupiter. This made Pioneer the fastest manmade object to leave the Earth,
fast enough to pass the Moon in 11 hours and to cross the Mars orbit, about 80
million kilometers (50 million miles) away, in just 12 weeks.
On 15 July 1972 Pioneer 10 entered the Asteroid Belt, a doughnut shaped area
which measures some 280 million kilometers wide and 80 million kilometers
thick. The material in the belts travels at speed about 20 km/sec. and ranges
in size from dust particles to rock chunks as big as Alaska.
After safely traversing the Asteroid Belt, Pioneer 10 headed toward Jupiter.
Accelerated by the massive giant to a speed of 132,000 km/hr (82,000 mph),
Pioneer 10 passed by Jupiter within 130,354 km (81,000 miles) of the cloudtops
on December 3, 1973. During the passage by Jupiter, Pioneer 10 obtained the
first close-up images of the planet, charted Jupiter's intense radiation belts,
located the planet's magnetic field, and discovered that Jupiter is
predominantly a liquid planet.
Following its encounter with Jupiter, Pioneer 10 explored the outer regions of
the Solar system, studying energetic particles from the Sun (Solar Wind), and
cosmic rays entering our portion of the Milky Way. The spacecraft continued to
make valuable scientific investigations in the outer regions of the solar
system until its science mission ended on March 31, 1997. Since that time,
Pioneer 10's weak signal has been tracked by the DSN as part of an advanced
concept study of communication technology in support of NASA's future
interstellar probe mission. The spacecraft had also been used to help train
flight controllers how to acquire radio signals from space during the Lunar
Prospector mission. The power source on Pioneer 10 finally degraded to the
point where the signal to Earth dropped below the threshold for detection in
its latest contact attempt on 7 February, 2003. The previous three contacts had
very faint signals with no telemetry received. The last time a Pioneer 10
contact returned telemetry data was on 27 April 2002.