WASHINGTON, DCA NASA poll conducted to gauge support for President Bush's space-exploration initiative revealed that a depressing 57 percent of Americans believe that the U.S. already has a research base on the moon. 'We put that international space-station thing up there in the '60s,' phone-poll respondent Randy Snow said. 'It might be on Mars, but I think it's the moonwherever they have the golf course that President Kennedy played on. Remember, the Cubans tried to take it over?' NASA officials said they hope someday to make Americans' perception a reality. 