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.
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.