Oct 31, 2009

Planet-Hunting Kepler Telescope Lifts Its Lid

The hunt is on. The Kepler spacecraft opened to the universe this week and is getting set to search for Earth-size planets around distant stars. Perhaps we'll find a home for E.T. I'm simply thrilled that this critical next step went off without a hitch.

On Tuesday evening, the Kepler spacecraft blew its lid. Well, actually it was a lot calmer than that; the cover was ejected in a carefully engineering maneuver.

At 7:13:36 PM, engineers at Kepler's mission operations center at the Laboratory for Atmospheric and Space Physics (LASP), Boulder, Colo., sent commands to pass an electrical current through a "burn wire" to break the wire and release a latch holding the cover closed. The spring-loaded cover swung open on a fly-away hinge, and then drifted away from the spacecraft.

The teloscope's oval-shaped dust cover, measuring 1.7 meters by 1.3 meters (670 inches by inches), protected the photometer from contamination before and after launch. The dust cover also blocked stray light from entering the telescope during launch-v light that could have damaged its sensitive detectors.

In addition, the cover was important for calibrating the photometer. Images taken in the dark helped characterize noise coming from the instrument's electronics, and this noise will later be removed from the actual science data.

"The cover released and flew away exactly as we designed it to do," said Kepler Project Manager James Fanson of NASA's Jet Propulsion Laboratory, Pasadena, Calif. "This is a critical step toward answering a question that has come down to us across 100 generations of human history-are there other planets like Earth, or are we alone in the galaxy?"

"Now the photemeter can see the stars and will soon start the task of detecting the planets," said Kepler's Science Principal investigator William Borucki at NASA's Ames Research Center, Moffett Field, Calif. "We have thoroughly measured the background noise so that our photometer can detect minute changes in a star's brightness caused by planet."

Deputy Principal Investigator, Dr. David Koch, watched the cover ejection from NASA Ames Research Center, celebrating with the kepler Science Operations Center team.

"Besides launch, this was the most critical event for the Kepler spacecraft, and everything went as expected," he said. "The spacecraft settled after the ejection, and the star trackers were rock solid. The first images have been taken, and we look forward to reviewing those shortly. It was a truly exciting event."

With the cover off, starlight is entering the photemeter and being imaged onto its focal plane. Engineers will continue calibrating the instrument using images of stars for another several weeks, after which science observations will begin.

By Edna DeVore, SETI Institute, www.space.com

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