"Doomship" by Frederik Pohl & Jack Williamson
Short story, definitely no later than the 1980s,
Written in 1973-4 or so
in which there’s a chap on Mars (I think - could be the moon or another planet) in a base or ship (can’t recall which) that’s failing. He steps in the teleport and walks out at the other end on Earth to (I think) a hero’s reception. Meanwhile, back on Mars, the original man sits down to look towards Earth and awaits his death.
The doomship is a probe that is encountering an odd astronomical phenomenon at the edge of space. It is crewed by copies sent to it by teleportation. But on the ship, the combination of radiation and high G in the probe are killing everyone. He needs to send a second copy to find out why the probe-ship seems to be going bad. The goal is to create an orbiting station.
Everyone sent will die, but the sender is fine back home. They might get a plaque later.
Turns out the person organizing the 'revolt' to make the probe fail is his own first copy
The point is about how their teleports don't physically transport the man, but read his make up and reconstruct him at the other end.
This is exactly how it works.