It'd be great if anyone could remember the source of this short story I only dimly remember, but recall finding quite haunting back in my youth. I read it maybe 20 years ago in a paperback that probably dated from the '80s.
It begins with the protagonist (a young man) being being woken by a deafening noise coming through his cochlear implant. He's on a spaceship, and has volunteered to be put in a capsule and fired off to a remote part of the solar system.
Once in place in their capsule, the volunteers are visited by what is (presumably) a highly intelligent alien life-form, and gifted with some artefact containing priceless knowledge, like, for example, the cure for cancer.
The (unexplained) encounter leaves the them completely and irrevocably insane, perhaps terrified out of the minds. Yet despite this, volunteers still clamour to be chosen for the mission.