Tunnel in the Sky

Tunnel in the Sky by Robert A. Heinlein. mass_market edition. ISBN: 9780345353733.

It was just a test . . . But something had gone wrong. Terribly wrong. What was to have been a standard ten-day survival test had suddenly become an indefinite life-or-death nightmare. Now they were stranded somewhere in the universe, beyond contact with Earth . . . at the other end of a tunnel in the sky. This small group of young men and women, divested of all civilized luxuries and laws, were being forced to forge a future of their own . . . a strange future in a strange land where sometimes not even the fittest could survive! ". . . fascinating . . . ingenious . . . this a book in the grand tradition of high literature!" -- The New York Times