New Sky-mapping Observatory Sheds Lens Cap to Soak in Starlight

NASA's new cosmic mapper successfully jettisoned a protective lens cover last week, opening its infrared eyes to Universe for an unprecedented survey in 2010.

A United Launch Alliance Delta 2 rocket delivered the Wide-field Infrared Survey Explorer spacecraft into polar orbit from Vandenberg Air Force Base in California on December 14.

The cover was secured atop the Thermos-like bottle structure that holds the observatory's telescope and state-of-the-art detectors in super-cold frozen hydrogen. The cap was designed to keep out light during the early days of the mission while controllers ensured the spacecraft's orientation system would operate correctly, preventing an accidental blinding by looking at the sun or down at Earth.

The one-month checkout and preparatory period for the observatory achieved its key milestone when the cover was commanded to separate at about 5:30 p.m. EST (2230 GMT). Pyrotechnic devices fired to release nuts holding the cover in place, then three springs ejected the small structure away from WISE and into a lower orbit.

"The cover floated away as we planned," said William Irace, the WISE project manager at NASA's Jet Propulsion Laboratory. "Our detectors are soaking up starlight for the first time."

Upcoming on the agenda for mission control will be the tweaking of relative motions between the spacecraft itself and the internal scanning mirror that will enable "freeze-frame" snapshots to be taken of the sky every 11 seconds as WISE circles the planet.

"It's wonderful to end the year with open WISE eyes," said Peter Eisenhardt, the mission's project scientist at JPL. "Now we can synch WISE up to our scan mirror and get on with the business of exploring the infrared Universe."

The mapping project should start in mid-January, with the first public release of WISE imagery expected in mid-February.

WISE will have a scant nine months to perform its full-sky survey before the solid hydrogen that's needed to keep its infrared optics cold is gone.

The mission promises to discover millions of objects never seen before, writing an authoritative new atlas that will be referenced by space- and ground-based observatories for countless years to come.

The infrared nature of WISE allows the craft observe the heat emitted from unknown objects either hidden behind dusty veils or impossible to see in visible light. The telescope will be capable of imaging the glow from targets ranging in temperature from -330 degrees F to 1,300 degrees F.

Scientists expect to find several hundred asteroids that pass close to Earth, failed stars in our solar system's backyard and ultraluminous galaxies where new stars are being created at astonishing rates, all of which will be revealed to humans for the first thanks to WISE.

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