Five decades of exploration: Buzz Aldrin on the Moon in 1969 - arguably NASA's finest hour.
Credit: NASA
This decision will be "probably made" by the next president, according to John Logsdon, former director of the George Washington University's Space Policy Centre.
In comments intended for Congress in March, but edited by the White House Office of Management and Budget, Griffin expressed concern at the future.
"A Chinese landing on the Moon prior to our own return will create a stark perception that the U.S. lags behind not only Russia but also China in space," he wrote in an internal email leaked recently to the media.
Sources close to NASA say Griffin is convinced China could technically put men on the Moon by 2017, two years before the Americans plan to return there. China mounted a successful third manned orbital mission and first space walk last week (see, Chinese complete successful spacewalk , Cosmos Online).
