Do GPS satellites compensate for Special and General Relativity? I’ve heard that somewhere, probably not true, most likely an urban legend.
(I’m tempted to say they need a treadmill, but I won’t) 
Wait. What’s the difference between a T-H-O-E-R-Y, like the OP is asking about and a T-H-E-O-R-Y? I’m familiar with the latter, but not the former.
There may be some truth to it. It seems like I heard something like that fairly recently.
Once, I read this thing about Apollo 16, where they had an atomic clock onboard, and it registered that the astronauts had spent milliseconds more on the mission than they would have had they stayed home.
The Punchline: “They were not paid any overtime.”
Ok, quote might not be perfectly word-for-word.
Wouldn’t it have been the other way around? A clock under acceleration runs more slowly, so the astronauts spent a few microseconds *less * time than the ground crew.
The majority of the trip was not made under acceleration, while terrestrial based clocks are under constant (1g) acceleration.*
*That’s why the GPS system is related specially to Einstein. I know it’s true cuz I heard it on the innernets.
Fair enough. Ignorance fought.
It isn’t that hard to get relativistic effects that are measureable. Here is a fellow who did it on a family vacation with the kids:
So his GPS was off? I’m confused.