The MX was originally designed using English units, then the edict came to convert it to SI units. By the time it was "Peacekeeper" the edict had come back to put it into English units. There were some pretty strange drawing callouts as a result.
Posted By: HoopUte
Date: Sunday 9 June 2019, at 07:54 pm Recommended by
Also, all the standards for commercial space launch vehicles like payload interfaces, fairings and interstages, etc. are done in SI units so that they can sell their wares easier internationally . I always thought it was telling on Delta IV that we were making 4-m and 5-m fairings, but for Delta IIs we were making 10-ft shrouds.
Last I was taking a look at them NASA specs were all in SI units. It's just easier.