asteroid tracks
January 24, 2014

NEOWISE Marks Its First Month Back In Service

Brett Smith for - Your Universe Online

Once a hibernating craft drifting silently through space, NEOWISE was repurposed and reactivated last month with a new mission – find asteroids and other potentially hazardous near-Earth objects (NEO).

On Thursday, NASA announced that the probe has identified 857 minor bodies in our solar system, including 22 NEOs and four comets, in its first 25 days of operation. Three of these NEOs are new discoveries measuring hundreds of feet in diameter.

The space agency added that NEOWISE has passed its post-restart survey readiness review, confirming that the project is able to determine asteroid positions and brightness with the same competence as before it entered hibernation in early 2011.

Formerly known as the Wide-field Infrared Survey Explorer (WISE), the orbiter was shut down in 2011 after completing the most comprehensive survey ever of asteroids and comets. The craft was reactivated as the Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) and its first discovery since coming out of hibernation was a never-before-seen asteroid dubbed 2013 YP139, NASA announced earlier this month.

“We are delighted to get back to finding and characterizing asteroids and comets, especially those that come into Earth’s neighborhood,” Amy Mainzer, the mission’s principal investigator from NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif., said upon announcing the discovery. “With our infrared sensors that detect heat, we can learn about their sizes and reflectiveness.”

NEOWISE spotted the newly-named asteroid on Dec. 29. Using a computer analysis, mission scientists were able to detect the moving object against the backdrop of stationary stars. The Earth orbiter was able to observe 2013 YP139 several times over half a day before the asteroid moved outside its view.

Researchers at the University of Arizona and Peter Birtwhistle, an amateur astronomer at the Great Shefford Observatory in West Berkshire, UK, helped to confirm the find via follow-up observations.

The newly-discovered asteroid is currently about 27 million miles from Earth. An infrared analysis showed that 2013 YP139 is approximately 0.4 miles in diameter and extremely dark in coloration, like a giant piece of space coal. The asteroid travels around the sun in an elliptical orbit tilted just off the plane occupied by our Solar System’s planets. Considered potentially hazardous, NASA said the asteroid’s orbit will bring it as close as 300,000 miles from Earth, just past the distance to the moon. However, this flyby will not take place within the next century.

NASA expects 2013 YP139 will be the first of hundreds of asteroid discoveries for NEOWISE and as the observatory continues to spot asteroids and comets – the observations will be directed to the clearinghouse for solar system objects known as the Minor Planet Center in Cambridge, Mass. At the clearinghouse, potential discoveries are compared against the existing catalog of solar system objects. Follow-up observations are then conducted by a community of professional and amateur astronomers to establish firm orbits for any previously undetected objects.

“The spacecraft is in excellent health, and the new images look just as good as they were before hibernation,” Mainzer said in December after NEOWISE came out of hibernation.