President Trump was pretty dumbfounded after learning NASA astronauts are drinking their own urine in space ... and he has a message for them -- "Better you than me!!"
The prez on Monday asked Peggy Whitson -- who video chatted as the new NASA record holder for most days in space -- what astronauts are learning up there.
Peggy revealed this golden nugget -- astronauts are purifying their urine to make it drinkable!
Trump's reaction to the news is written all over his face, but he pulled it together to voice the perfect comeback.