NASA has shot down a new Russian theory on the failure of its Phobos-Grunt martian moon probe: that the craft was damaged by asteroid-tracking radar signals from a U.S. installation in the Marshall Islands, The Washington Post reports.

Russia’s Kommersant newspaper quoted an unidentified Russian space official as saying, “There is a possibility that the station accidentally entered the area covered by the radar, which resulted in a failure of its electronics caused by a megawatt impulse. After that, it could no longer give a command to switch on the Phobos propelling system.”

But NASA spokesman Bob Jacobs said the agency’s scientists were not using the Marshall Islands radar to track an asteroid on Nov. 9, the day of the Phobos-Grunt launch.