It took a little extra effort, but NASA this weekend
bridged a nearly seven-and-a-half billion mile span to make
contact with Pioneer 10, a plucky space probe that first left
Earth’s gravitational pull more than 30 years ago.

On Friday, scientists at the NASA Jet Propulsion Laboratory’s
(JPL) Deep Space Network in Goldstone, Calif., sent a signal
to the spacecraft, which is still hurtling toward the fringes
of the solar system. Twenty-two hours later, at 1:47 p.m.
EST, researchers at the network’s facility in Madrid, Spain,
carefully monitoring a 70-meter dish antenna, heard Pioneer’s
response.

“We are overjoyed that we still have the spacecraft,” said
Robert Hogan, chief of NASA Ames Research Center’s Space
Projects Division, where the Pioneer project is managed.

“As an eternal optimist, I was confident it would succeed.
Pioneer 10 has been discounted in the past, but somehow it
always manages to land on it feet,” recalled Pioneer 10
Project Manager Dr. Larry Lasher of Ames, located in
California’s Silicon Valley. “This success is a testament to
good solid design.”

“From Ames Research Center and the Pioneer Project, we send
our thanks to the many people at the Deep Space Network and
JPL who made it possible to hear the spacecraft signal
again,” said Pioneer 10 Flight Director David Lozier.

NASA previously lost contact with Pioneer 10 in August 2000,
but made contact again in April of last year by switching the
spacecraft to a different communications mode. NASA most
recently made contact with the spacecraft on July 9, 2001.

Launched on March 2, 1972, Pioneer 10, built by TRW Inc.,
Redondo Beach, Calif., is now 7.4 billion miles from Earth.
Pioneer 10 was the first spacecraft to pass through the
asteroid belt and the first to make direct observations and
obtain close-up images of Jupiter. During its tour of the
Jovian system, Pioneer 10 also charted Jupiter’s intense
radiation belts, located the planet’s magnetic field, and
established that Jupiter is predominantly a liquid planet.

In 1983, it became the first man-made object to leave the
solar system when it passed the orbit of Pluto, the most
distant planet from the Sun.

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. Pioneer 10’s
weak signal continues to be tracked by the Deep Space Network
as part of an advanced concept study of communications
technology. The probe was also used to help train flight
controllers how to acquire radio signals from space.

Pioneer 10 is headed toward the constellation Taurus, where
it will pass the nearest star in the constellation in about
two million years.

“Pioneer 10 has performed much better than expected,” added
Hogan, who is also a member of the original launch team for
the spacecraft. “It’s amazing that it’s lasted this long.”

Scientific data received from Pioneer 10’s Geiger-Tube
Telescope instrument is analyzed by original principal
investigator Dr. James Van Allen of the University of Iowa,
who discovered the Earth’s radiation belts bearing his name.
Based on the previous data received, Van Allen concluded that
galactic cosmic radiation is being moderated by the Sun’s
influence, meaning Pioneer 10 has not yet crossed the
boundary into interstellar space.

Further information about Pioneer 10 is available on the
Internet at:

http://spaceprojects.arc.nasa.gov/Space_Projects/pioneer/PNho
me.html