WASHINGTON — NASA and the European Space Agency are about to pull the plug on a robotic solar probe that just wouldn't quit. The Ulysses probe was launched from the space shuttle Discovery in 1990. It was supposed to last five years. But it's now nearing 19 years, 5.8 billion miles and still going.

Sixteen months ago, the two space agencies announced that Ulysses was freezing up and about to die in a matter of weeks. Somehow it kept operating, sending important science information about an extraordinarily quiet year for the sunspots and solar wind.

That will end on Tuesday when the space agencies turn off Ulysses' transmitter. Officials say issues with power, location and antennas make it no longer useful.