Past Jupiter and heading for deep space
From a distance of almost 12 billion kilometres, Pioneer 10 has contacted Earth reporting that one of its instruments is still working 30 years after it was launched.
On 2 March, scientists operating a radio telescope in Madrid, Spain, contacted Pioneer 10, duplicating a feat they accomplished last spring, when they hooked up with the spacecraft after a silence of eight months.
Dr Larry Lasher, of the American space agency's (Nasa) Ames research center, and Pioneer 10 Project Manager, said: "There it was, right on time; it came in loud and clear and strong."
Launched on 2 March, 1972, Pioneer 10 was the first spacecraft to pass through the asteroid belt and the first to take close-up images of Jupiter. In 1983, it became the first man-made object to leave the Solar System when it passed the orbit of the most distant planet.
After passing Jupiter, the spacecraft continued to make valuable scientific investigations in the outer regions of the Solar System until its science mission ended on 31 March, 1997. It is now heading toward the constellation Taurus (the Bull), where it will pass the nearest star in the constellation in about two million years.
'Better that expected'
Despite the formal end of the mission, Pioneer 10's weak signal continues to be tracked as part of an advanced concept study of communications technology.
"Pioneer 10 has performed much better than expected," said Robert Hogan, chief of Ames' Space Projects Division, where the Pioneer project is managed. "It's amazing that it's lasted this long," added Hogan, who is also a member of the original launch team for the spacecraft.
The latest contact with the probe was made a few days ago from a distance of 12 billion kilometres (7.4 billion miles). The spacecraft is extremely cold, with many of the temperature readings at the bottom of their scales.
One scientific instrument is still working, the Geiger Tube Telescope, and its chief scientist, Dr James Van Allen, has been told by Nasa that he has some more data to look at.
According to Dr Van Allen, Pioneer 10 is still travelling through the Sun's extended outer atmosphere and has yet to reach its boundary, the heliosphere. Scientists say knowledge of this boundary will help define the extent of our Sun's influence.