story identification - which novel involved sending instantaneous tachyon body copies around the galaxy, mostly to die?

The novel centers around a man living a comfortable existence in the pretty distant future. To support himself, he is occasionally asked to enter a box which will copy his entire body, and send it out faster than the speed of light to some developing world, to work.

His copy on this world wakes up and realizes what a big mistake he's made. The copy does grueling work, feels lonely, and eventually just dies of radiation sickness. Back on earth, the man never realizes how bad it is out there, and keeps sending out more copies.

I think the story is probably 80s or earlier - not sure if it's a short story, or the beginning of a novel which I lost & never finished.

Answer

This could be Farthest Star by Frederik Pohl and Jack Williamson. That book definitely has the concept of sending out copies as a means of travelling faster than light, and at least one of the copies dies of radiation sickness. Other copies, though, do survive, and in fact send out copies of their own.

One point that might help to clinch the identification is that in that book, the main character (or his copies) developed the habit of giving himself a new middle name each time he finds himself in a new copy.