Space exploration

NASA waking telescope to join asteroid hunt


LOS ANGELES — The space-based telescope known as WISE has been hibernating in Earth orbit for the past two years, but nap time is over.

WISE has some asteroid-hunting to do.

NASA announced this week that it will put the space telescope back to work, focused on finding hazardous asteroids and other space rocks that could come uncomfortably close to Earth.

NASA hopes the infrared telescope still has enough juice to discover 150 previously unknown near-Earth objects and to help scientists learn more about the shape and size of 2,000 others, the agency said in a statement.

It might even help the agency find the perfect asteroid for it to capture and land a spacecraft on this decade.

WISE, the Wide-field Infrared Survey Explorer, was launched in December 2009, tasked with scanning the night sky in infrared light, looking for heat emanating from galaxies, stars and asteroids.

By the time its primary mission ended in February 2011, WISE had captured more than 2.7 million images in multiple wavelengths and cataloged more than 560 million objects in space, NASA said.

In a separate mission, dubbed NEOWISE, the telescope also made the most-accurate survey of near-Earth objects to date.

When the mission was over, the scientists decided to put it to sleep rather than turn it off completely.

“We turned off the cameras and all the unnecessary electronics, and what was left was basically enough power to keep its solar arrays pointing toward the sun so it can still get power,” said Amy Mainzer, principal investigator for NEOWISE at the Jet Propulsion Laboratory.

Waking up the telescope and putting it back to work shouldn’t be too hard, said Mainzer, but the first step is to cool it down.

“The temperatures have warmed up to about 200 degrees above absolute zero, which sounds cool to us on Earth but is actually quite warm for an infrared telescope,” she said.

Because all its refrigerants are long gone, WISE will be cooled off by having it stare into deep space for a bit.

“When it looks at the cold background of deep space, most of the heat will radiate away,” Mainzer said.