Gateway - Pohl

This was the 1977 Hugo Award winner.

'Gateway' is a book about voyages into the unknown. Not the warm fuzzy places of the 'Star Trek' universe, but a frighteningly dangerous place with a known (and high) mortality rate. How much can be risked to win riches? Especially when the risks are beyond your control?
The story is about a man names Robinette, and his work to come to grips after one of these voyages. The chapters alternate between his description of the past and his current time sessions with a computer psychiatrist. The juxtaposition works quite well. You know that something terrible has happened but not what it was.
Robinette has won the lottery on Earth and used the money to go to a hollowed out asteroid called 'Gateway'. This asteroid was a found artifact from an alien race. It features nearly a thousand small starships. Humanity has figured out how to start the ships, but not how to steer them. Volunteers go into them and out to the stars. If they come back with something scientifically interesting, they can become very, very rich. If they come back at all. The mortality rate is high and everyone knows it.
Living on Gateway is expensive. The only way a volunteer can afford to stay there is to keep taking trips. If their nerve fails then they are quickly ruined. Despite the dangers, they have to keep going out. But if they score well . . . they are set for life.
I'd never heard of this book before and that's a shame. It's a great one. The ideas are interesting, the characters are compelling and the growing sense of danger is outstanding.