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Landsat 5 Imaging Halted To Solve Latest Glitch

WASHINGTON-- Technical difficulties with a piece of equipment on the Landsat 5 satellitecould mean the end of operations for the 21-year-old remote sensing spacecraft.

The U.S. GeologicalSurvey confirmed Nov. 28 that Landsat 5 started experiencing problems with itsback-up solar array drive Nov. 26. The device's function is to keep the solarpanels pointed toward the Sun. When the drive's rotation became sporadic, itprevented the solar panels from generating enough power to charge thesatellite's batteries.

"How itcould get fixed is going to be the subject of much discussion with ourengineers over the next few weeks," Jay Feuquay, coordinator of the land remotesensing program at the U.S. Geological Survey, said in an interview Nov. 28."We're cautiously optimistic we will be able to resume some sort of operations,but we don't know that for sure, and we don't know how close to full operationswe'd be able to get."

It is possibleLandsat 5 will still be able to operate for more limited use, but details onhow that could happen are still unclear, according to Feuquay.

"We'll haveto work around whatever the onboard systems are," he said. "It's really whetheror not the smart guys doing our engineering are going to be able to pull onemore rabbit out of their hat."

Landsat 5already is operating on its back-up solar array drive. Its primary array failedin January.

Feuquaysaid scientists should be able to determine what Landsat 5's future is withinthe next two weeks or so. In the meantime, imaging operations have beensuspended for the satellite.

Landsat 5,which launched in March 1984, originally was designed with a three-year shelflife, but has been operating beyond its expected capability until now. Thegovernment's other remote sensing satellite, Landsat 7, has its own problems,as its main sensor malfunctioned in 2003, causing it to deliver degraded datasince then.

White Housepolicy officials are still deliberating the next course for the Landsatprogram; a policy decision last year would have put a Landsat imager on theNational Polar-orbiting Operational Environmental Satellite System (NPOESS),but problems with NPOESS have made that alternative less likely.

The WhiteHouse Office of Science and Technology Policy (OSTP) is weighing whether tolaunch a free-flying Landsat satellite in the meantime as an alternative. OSTPspokesman Donald Tighe did not return a call for comment Nov. 28. Feuquay saidthe U.S. Geological Survey still is waiting to hear from the office on theirfinal decision, though he confirmed a free-flyer mission is among thealternatives being weighed.

Industryrepresentatives who rely on Landsat data have been lobbying governmentofficials this month with concerns that the lack of decision on how to goforward with Landsat will result in a data-gap where no remote sensing data isbeing collected for an extended period of time.

Organizationsthat have sent letters urging a quick decision include the ManagementAssociation for Private Photogrammetric Surveyors, the American Society ofPhotogrammetry and Remote Sensing, and the National Satellite Land RemoteSensing Data Archive Advisory Committee.

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