When are the astronauts coming back from Mars?

Never.

The little dwarf astronauts who are presently welded into the hull of the lander have a mission to tear-arrse across the surface as fast as they can in an attempt to beat the current world land speed record, which should be easy seeing there is no air on Mars.

After that they will cut open the lander using the can-opener they were provided, and they will then plant a flag, and dig tunnels into Mars where they will copulate profusely and populate Mars.

There are no astronauts on Mars.

No Austronauts have not went to Mars currently. just a rover named preservance has went

Never.

then journey from Earth to Mars takes over half a year. There's no way to carry along enough food and fuel for the journey back.  If people go there. it's a one-way suicide-mission.

The athmosphere is too thin, and Mars' magnetic field too weak, to properly protect any humans anyway

There are NO Astronauts on Mars.  Just a Robot Rover.

No one's gone to Mars...

yet.

Sorry, but didnt you here? they died in a dust storm a week ago.

They are not coming back. They wish to hang around and eat Snickers.