Book from circa 1983 about a man who can teleport into different copy bodies of himself

Question

The story centers around a man who can teleport into different copy bodies of himself. I believe much of the book takes place on Mars but they also visit Mercury and I believe the moon. One of the things that stood out was instead of using spacesuits they took pills called goofballs that supplied them with air.

Answer 1

The Sirens of Titan, a novel by Kurt Vonnegut, Jr.; first published in 1959, reprinted in many editions.

From the Wikipedia summary:

Malachi Constant is the richest man in a future America. He possesses extraordinary luck that he attributes to divine favor which he has used to build upon his father's fortune. He becomes the centerpoint of a journey that takes him from Earth to Mars in preparation for an interplanetary war, to Mercury with another Martian survivor of that war, back to Earth to be pilloried as a sign of Man's displeasure with his arrogance, and finally to Titan where he again meets the man ostensibly responsible for the turn of events that have befallen him, Winston Niles Rumfoord.

Rumfoord comes from a wealthy New England background. His private fortune was large enough to fund the construction of a personal spacecraft, and he became a space explorer. Traveling between Earth and Mars, his ship—carrying Rumfoord and his dog, Kazak—entered a phenomenon known as a chrono-synclastic infundibulum, which is defined in the novel as "those places ... where all the different kinds of truths fit together." When they enter the infundibulum, Rumfoord and Kazak become "wave phenomena", somewhat akin to the probability waves encountered in quantum mechanics. They exist along a spiral stretching from the Sun to the star Betelgeuse. When a planet, such as the Earth, intersects their spiral, Rumfoord and Kazak materialize, temporarily, on that planet.

The story centers around a man who can teleport into different copy bodies of himself.

Winston Niles Rumfoord is not the central character but the next most important character in the book; he does not exactly teleport but he's in a weird condition which causes him to materialize in different places.

I believe much of the book takes place on Mars but they also visit Mercury and I believe the moon.

Parts of the book are set on Earth, on Mars, on Mercury, and on Saturn's moon Titan.

One of the things that stood out was instead of using spacesuits they took pills called goofballs that supplied them with air.

That's what clinched the identification. Excerpt, with emphasis added:

Unk's mate, the mother of young Chrono, `was in instructress in the Schliemann Breathing School for Recruits. Schliemann breathing, of course, is a technique that enables human beings to survive in a vacuum or in an inhospitable atmosphere without the use of helmets or other respiratory gear.

It consists, essentially, of taking a pill rich in oxygen. The bloodstream takes on this oxygen through the wall of the small intestine rather than through the lungs. On Mars, the pills were known officially as Combat Respiratory Rations, in popular parlance as goofballs.

Schliemann Breathing is at its simplest in a benign but useless atmosphere like that of Mars. The breather goes on breathing and talking in a normal manner, though there is no oxygen for his lungs to take in from the atmosphere. All he has to remember is to take his goofballs regularly.

The school in which Unk's mate was an instructor taught recruits the more difficult techniques necessary in a vacuum or in a harmful atmosphere. This involves not only pill-taking, but plugging one's ears and nostrils, and keeping one's mouth shut as well. Any effort to speak or to breathe would result in hemorrhages and probably death.