If Trump had been on the first flight to the moon in July 1969, he'd have tried

[raccoon]

to shove his way past Neil Armstrong so that he, DT, could be the (ta-da) first man on the moon.

OK, of course, Trump doesn't have 10% of the right stuff to be an astronaut. And Neil Armstrong would never have let DT push past him--or get anything past him.

Trump isn't fit to wipe Neil Armstrong's or Buzz Aldrin's space boots.

[Cary]

1. He ignored scientists about looking at the eclipse

He would also ignore them about using a spacesuit

[Pope George Ringo II]

2. He'd have tried to come back.

That would be the only part I really would have a problem with.

[DFW]

3. After being cooped up with Donald Trump for the time it took to get to the moon

I'm pretty sure Armstrong and co. would have found a perfectly legitimate reason to leave him there.

[kairos12]

4. He would have been the lunacy part of the landing.