I assume that the D850 does not have the rugged metal chassis of the D5 and NASA appear to prefer rugged cameras.
....
Without seeing actual specs, or images, one would assume it will be built the same as the D800's and D810 before it .. full magnesium alloy body.
Maybe not as rugged as a D3/4/5 series body, but a full metal jacket all the same.
What I'm surprised to not see in NASAs camera body lineup is the D810a.
D850 is as yet an unknown quantity, so it'd be foolish of NASA to send any up into space.
But D810 and D810a now have been around for a long time, are still relevant, provide reasonably high res images .. especially considering the specialised kind of image output that the D810a caters for.