After several cases where reports of its death were much exaggerated, the Ulysses space probe is to finally cease operations.

Exactly when is not entirely clear, as NASA says it will tell the probe to turn off its transmitter on “Monday, June 30”. Whenever Ulysses is actually put down, it deserves a round of applause, having spent over 18 years in space.

The old voyager has been on a strange orbit, speeding past the Sun’s poles three times to help researchers puzzle out the mysteries of the solar wind. As the European Space Agency, a partner with NASA on the mission, says, it has defied “several earlier expectations of its demise”, including a couple from Nature (see: Closer than ever to the Sun).

“We expected the spacecraft to cease functioning much earlier,” says Paolo Ferri, of ESA’s European Space Operations Centre. “Its longevity is a tribute to Ulysses’s builders and the people involved in operations over the years.”

Sadly though the scientific return on investment no longer justifies keeping Ulysses running. On the bright side, Richard Marsden, ESA’s Ulysses mission manager, notes that the probe will in effect become a man-made comet.

“Whenever any of us look up in the years to come, Ulysses will be there, silently orbiting our star, which it studied so successfully during its long and active life,” he tells MSNBC.

Headline watch

Ulysses Hears the Siren’s Song – NASA press release

Light goes out on solar mission – BBC

After 19 years, Ulysses solar probe to go dark – AP

Tales of brave Ulysses – Christian Science Monitor

Image: NASA