The interplanetary space probe Ulysses officially ceased operations on June 30, after an 18-year voyage of roughly 5.5 billion miles (8.85 billion km) and nearly three complete orbits around the sun, NASA said.
Radio contact with the Volkswagen-sized spacecraft was halted by ground controllers shortly after 1 pm PDT/4:00 pm EDT, but NASA project manager Ed Massey said Ulysses will continue its wide, elliptical orbit around Earth's local star indefinitely.
He said there was a chance the probe might eventually swing close enough to one of Jupiter's moons to alter its course and place it on a path that will take it out of solar system and into interstellar space. The spacecraft was about 437 million miles (705 million km) from the sun at the time that its transmitter was switched off, Massey said.
Ulysses, a joint project of NASA and the European Space Agency, was launched from the U.S. space shuttle Discovery in October 1990 and became the first probe to fly around the sun's poles. As of mid-June, it had logged 5.4 billion miles and nearly three complete solar orbits.
Named for the hero of "The Odyssey," Ulysses was designed to help scientists study solar radiation and was originally expected to last for just five years.