Gateway

Nebula Award 1977, Hugo Award 1978, Locus Award 1978.
RICH MAN, DEAD MAN
Those were the choices Gateway offered - the same for women, too, of
course. Gateway opened on all the wealth of the Universe... and on
reaches of unimaginable horror.
The humans who rode the alien Heechee spacecraft stored on the planetoid couldn't know whether the trip would make them millionaires or corpses.
When Bob Broadhead came out to Gateway, he thought his problem was
simple - wait till the mission felt right, then ship out. But watching
returned prospectors scraped from the insides of their ships, falling in love, feeling his nerve dwindle - all these things changed him.
Then, years later, Robinette Broadhead, a three-mission veteran, famous
and permanently rich, has to face just what happened to him and what he
is... in a journey into himself as perilous and even more horrifying
than the nightmare trip through the interstellar void he finally drove
himself to take!
Frederik Pohl
Frederik George Pohl, Jr. (1919-2013) was an American science fiction writer, editor and fan, with a career spanning over seventy years. From about 1959 until 1969, Pohl edited Galaxy magazine and its sister magazine If, winning the Hugo for if three years in a row. His writing also won him three Hugos and multiple Nebula Awards. He became a Nebula Grand Master in 1993.
Frederik Pohl used these pseudonyms: Edson McCann, Jordan Park, Elton V. Andrews, Paul Fleur, Lee Gregor, Warren F. Howard, Scott Mariner, Ernst Mason, James McCreigh, Dirk Wilson, Donald Stacy and James MacCreigh.
Heechee Saga
Series contains 5 primary works and has 6 total works. Current series reading order on below.