@adamshostack Sadly I've also encountered places where US customary units are used in a space technology context. When I was told something in terms of feet, I had to resist the urge to ask "but which king's feet are these?" On the up side, that was the day I learned that the foot is now defined to be exactly 0.3048 m.
@adamshostack Time (and space) dependant use of units just makes me think of grue and bleen.
@adamshostack clearly an idea to come from a committee with a majority preference for geostationary orbits.
@internic US units are to be used when above US territory; at all other times metric units are to be used. The point of transition is when the craft center of gravity crosses a border created by uniformly expanding Earth, and at time of crossing at the craft location without regard for speed of light.
(Obviously!)