NASA lost contact with Pioneer 10, the space probe launched in 1972 on a mission of less than two years which just kept on going and defying the experts.

Pioneer 10 was the first vessel from Earth to pass through the asteroid belt and send back close-up images of Jupiter.

Just in case it came across other life forms, the space ship carried on board a gold plaque carrying images of humans, a map showing where Earth is and the date of its launch: March 2, 1972.

But it Pioneer's longevity which astonished scientists and the mission was hailed by the National Aeronautics and Space Administration (NASA) after it announced that it received the last signal on January 22.

Officials said the last of three efforts to contact the space craft on February 7 had failed. Experts had concluded that Pioneer 10's radioisotope power source had finally broken down after three decades of loyal service.

Propelled by the most powerful engine ever used for a space craft, Pioneer 10 was fastest craft to leave the Earth, able to reach the Moon in 11 hours and Mars in 12 weeks.

It entered the asteroid belt in 1972 and passed Jupiter in December 1973, sending pictures of the planet back to Earth and charting the gas giant's radiation belts, locating its magnetic field and establishing that Jupiter is mainly liquid.

Accelerating to 131,000 kilometers (82,000 miles) an hour, Pioneer 10 then powered away to reach Pluto, the furthest planet from the Sun -- and explore the outer regions of the solar system, studying solar winds and portions of the Milky Way.

After March 31 1997, the probe had been sending only a faint signal, powered by its fast fading batteries. The last flight information was sent on April 27 last year.

At the time of its last signal, Pioneer 10 was 12.2 billion kilometersbillion miles) from Earth. At the speed of light, its radio signal took 11 hours to reach Earth.

"It ranks among the most historic as well as the most scientifically rich exploration missions ever undertaken," said Colleen Hartman, director of NASA's Solar System Exploration Division.

"Pioneer 10 was a pioneer in the true sense of the word. After it passed Mars on its long journey into deep space, it was venturing into places where nothing built by humanity had ever gone before," Hartman added.

"Originally designed for a 21-month mission, Pioneer 10 lasted more than 30 years," said project manager Larry Lasher. "It was a workhorse that far exceeded its warranty, and I guess you could say we got our money's worth."

The probe may send no more signs of life but it is still ploughing a pioneer path deep into space.

At the time contact was lost, Pioneer 10 was heading toward the red star Aldebaran, which forms the eye of the constellation Taurus. It should reach there in about two million years.