Dolores Beasley
Headquarters, Washington
(Phone: 202/358-1753)

Michael Mewhinney
Ames Research Center, Moffett Field, Calif.
(Phone: 650/604-3937)

RELEASE: 02-44

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: