Goodbye Ulysses, enjoy infinity.

NASA and ESA are set to end the mission of the solar spacecraft Ulysses, which has been operating for more than 18 years (Illustration: NASA)

Ground controllers will pull the plug on the solar probe Ulysses on Tuesday, ending an epic mission that has lasted more than 18 years.

Ulysses launched in October 1990 and swung past Jupiter in 1992, putting it into an orbit that crosses the sun's poles – the first and only spacecraft ever to do so.

Over its lifetime, the probe has flown through three comet tails, studied the magnetic fields around the sun and Jupiter, and found interstellar dust blowing through the solar system.

NASA and the European Space Agency, which jointly operate the mission, had earlier predicted that Ulysses would die in 2008, when low power threatened to freeze the probe's remaining fuel. But the spacecraft team managed to prevent that from happening by firing its hydrazine-powered thrusters every two hours.

Now the probe's fuel is running low, and the space agencies have decided to turn off its transmitter, which allows it to receive its life-sustaining commands, on Tuesday. "We'd already gone a year more than we thought we could, so we thought it would be a good time to get out," says Ed Massey of NASA's Jet Propulsion Laboratory in Pasadena, California and NASA project manager for Ulysses.