- You may be looking for the eponymous comic story.
The Infinite Astronaut was the legal description of anyone who claimed the right to seek and to see and to be sent through the Gate of Creation. Claiming this right was a way to force a ceasefire in the Eternal Dogfight between the Amstrons of the Great Wheel and the J'arrodic Federation. The successful return of Infinite Astronauts, who had to be of the challenging species, could put an end to the Eternal Dogfight. However, if Infinite Astronauts failed to return from the universe beyond the Gate, their planet was to be destroyed by the Amstrons and J'arrodic.
The name originated from the first starship Infinite sent through the gate. All Infinite Astronauts had to travel in an exact reproduction of the original Infinite, which was considered to be sacred (the rules also permitted travelling in the original Infinite itself, which was impossible given that the original starship never returned from beyond the gate). Although it was common to refer to the Infinite Astronaut in the singular, the Infinite was a two-man craft and, hence, Infinite Astronauts typically travelled in pairs.
After the original Amstron and J'arrodic astronauts failed to return in the original Infinite, many other Infinite Astronauts have been sent through the Gate of Creation. The first to return were Alice Obiefune and John Jones, the Infinite Astronauts from Earth. Their return in 2015 finally put an end to the Eternal Dogfight. (COMIC: The Infinite Astronaut)