Oh I love space questions.
I would hope I will be in a spaceship at this point. I would like to look at earth, only a few privileged humans have ever seen the whole earth.
If I could, I would go on the Moon and plant a UK flag, it would probably annoy America (specifically Trump) and will probably encourage America to try and reach the moon again (yay space exploration).
I would like to do some experiments on the plants that see if they can survive a martian environment.