Trailblazing Spacecraft Falls Silent After 31 Years

The US space agency Nasa yesterday announced the death of one of its most enduring missions - Pioneer 10.

After 31 years, the trailblazing spacecraft has fallen silent, an estimated 7.6bn miles from Earth, and is heading towards the red dwarf Aldebaran in the constellation Taurus.

Pioneer 10 set off in 1972, during President Nixon's Watergate crisis. It carried a gold plaque depicting humankind, for the benefit of any puzzled extraterrestrial. It sped past the moon in 11 hours and crossed the orbit of Mars in 12 weeks. It negotiated the asteroid belt and accelerated past Jupiter at 82,000mph in December 1973.

The mission was only designed to last 21 months, but somehow the craft's plutonium powerpack kept going and it kept sending back messages.

In 1983, it passed the orbit of Pluto and became the first spacecraft to leave the solar system. The signals got weaker. In 2000 it sent a faint beep measured at a third of a billion trillionth of a watt. It last radioed Earth on January 22. Nasa tried again this month, and heard no response. Yesterday it declared Pioneer 10 dead to the world, but still heading for the stars.

"It was a workhorse that far exceeded its warranty," said a spokesman.