Twelve years after the shuttle Challenger explosion, the notion of allowing private citizens to pay to fly in space is being taken seriously in Congress and elsewhere.

A study by NASA and the private Space Transportation Association concluded in March that "im-me-diate steps can and should be taken" to encourage space tourism over the next few years."The idea that the risks of space flight are acceptable is gaining currency," says John M. Logsdon, director of George Washington Uni-ver-si-ty's Space Policy Institute of the Center for International Science and Technology Policy.

A St. Louis-based nonprofit organization called the X Prize Foundation is already trying to raise $10 million for the first team of entrepreneurs to build a private spacecraft that can carry three people on a suborbital flight up to 62 miles high on two consecutive trips within two weeks.

A Seattle company, Zegrahm Space Voyages, is taking reservations, with a $5,000 deposit, for trips starting in 2001. The cost: $98,000 a person.

House Space and Aeronautics Subcommittee chairman Dana Rohrabacher, R-Calif., said Congress and industry still have to reduce costs and find a way to address liability if accidents occur.

"We do know there will be failures," he said. "But there shouldn't be failures to the point where you never have tourism in space."