Famed as the most remote object ever made by man, at last contact Pioneer 10 was over 7.6 billion miles away from earth. (Until February 17, 1998, the heliocentric radial distance of Pioneer 10 had been greater than that of any other man-made object. But late on that date Voyager 1's heliocentric radial distance, in the approximate apex direction, equaled that of Pioneer 10 at 69.419 AU. Thereafter, Voyager 1's distance will exceed that of Pioneer 10 at the approximate rate of 1.016 AU per year). The spacecraft made valuable scientific investigations in the outer regions of our solar system until the end of its mission on March 31, 1997. The Pioneer 10's weak signal continued to be tracked by the Deep Space Network as part of a new advanced concept study of chaos theory. Before 1997 the probe was used in the training of flight controllers on how to acquire radio signals from space.
Pioneer 10 is headed towards the constellation Taurus. It will take Pioneer over 2 million years to pass by one of the stars in the constellation.
On Friday February 28, 2002, scientists at the NASA Jet Propulsion Laboratory (JPL)'s Deep Space Network in Goldstone, California, sent a signal to the spacecraft to see if it was still functioning. Pioneer 10 was eleven light-hours away at this point, and so it was twenty-two hours later when researchers at the network's facility in Madrid, Spain, heard Pioneer's response.
A later attempt in December 2002 received a faint response, which was too weak to decode. Pioneer 10's final signal (after two previous failures) was received on January 22, 2003. As of February 25, 2003, NASA came to the conclusion that the craft's radioisotope power source was no longer functioning well enough for further contact with Earth. NASA's Deep Space Network (DSN) did not detect a signal during the last contact attempt February 7, 2003. The previous three contacts, including the January 22 signal, were very faint with no telemetry received. The last time a Pioneer 10 contact returned telemetry data was April 27, 2002. NASA has no additional contact attempts planned for Pioneer 10.
As of February 5, 2002, Pioneer 10 was 79.66 AU from the Sun. The most recent cosmic ray data from the spacecraft, received on May 19, 2001, showed that the vehicle had not yet reached the heliopause.