Rocket to Limbo — Alan E. Nourse

The crew of the starship Ganymede were afraid their chief was losing his mind.
Commander Walter Fox had explored and opened up more colony-worlds than any other man alive - yet it was rumored that he still believed there were other intelligent beings in the galaxy.

Now as the ship grounded on unfamiliar terrain, the crew realized that the routine flight to Vega had been interrupted - and their worst fears were true . . .

They had landed on Wolf IV - the one planet from which no man had ever returned alive.