1.   But at the U.S. Centers for Disease Control and Prevention, the division that monitors emerging infectious diseases has not been asleep to the perils of space tourism.

2.   But serious people in the aerospace and travel industry are taking the idea of space tourism seriously.

3.   Entrepreneurs have their eyes on the X-Prize because of the unusual economics of space tourism.

4.   Even NASA concedes that space tourism of some kind is inevitable.

5.   Except for encouraging rhetoric, the space agency has written off lunar exploration and support for space tourism.

6.   NASA is serious about space tourism.

7.   None of the companies involved in space tourism will divulge their lists of potential clients.

8.   One private group is already trying to profit from space tourism.

9.   Since staying in space costs only a tiny fraction of what it costs to get into space, the profits in space tourism will be made on long trips.

10.   Space tourism, however, depends on the development of a rocket that can shuttle passengers cheaply and safely enough to sustain the potential tourism industry.