(Reuters) - A Romanian man accused of hacking into NASA computers at the Jet Propulsion Laboratory near Los Angeles under the online moniker "Iceman" has been indicted on a federal charge, prosecutors said on Wednesday.

Robert Butyka is charged with hacking into 25 NASA computers at JPL in December of 2010, causing $500,000 in damage and leaving researchers unable to use them for two months, U.S. Attorney's spokesman Thom Mrozek said.

The computers were part of the Atmospheric Infrared Sounder Program, which is used to support climate research and improve weather forecasting, he said.

Butyka, 25, a Romanian citizen who called himself "Iceman" online, was sentenced to three years in prison in Romania last month after being convicted there on similar charges, Mrozek said.

It was not clear if Butyka was currently serving that time in Romania but U.S. authorities would seek his return to the United States to face trial, Mrozek said.

The indictment, which was handed down by a federal grand jury in Los Angeles on Tuesday, charges Butyka with one count of unauthorized impairment of a protected computer.

If convicted he faces a maximum sentence of 10 years in prison.

The Jet Propulsion Laboratory is a federally funded research and development center and NASA facility that in recent years has managed the Mars Exploration Rovers, Mars Reconnaissance Orbiter and Cassini-Huygens probe to Saturn.

(This version fixes misplaced word in third to last paragraph)

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