Military-Spec Raspberry Pi Mission Computer Revealed
tomshardware.com
tomshardware.com
The compute module has 4 holes for bolts at its corners. If it's securely bolted to its board, with the correct spacers, I expect the contacts would experience no relative movement and be pretty good, at least until the vibrations are so severe that the bolts start to come off - but there are thread locker adhesives for those use cases.
--Edit: This is of course for the Compute Module only. The board it's bolted onto should of course be designed according to the use case - I doubt the Curtiss-Wright milspec thing shown in the article uses anything like the official Raspberry Pi IO Board, or the many semi-nameless ones you find on Amazon. I also doubt MicroSD is an option, given that I've had a card fly out of its socket in one extreme case.
Carrier board custom for product, but standard design approach. Entire design approach and some subassemblies and parts of it are TRL9.
CM4108032 does not have the SD option (no lines active on the CM4 board to board). Only CM4lite does that. Increased storage is via add on miniPCIe in expansion ring. This is TRL9.
MicroSD is TRL7 but not a great trade-off due to many issues and risk. Not supported.
Here is the best way I found to solve passive cooling with mechanical protection for civilian use: http://move.rupy.se/file/pi_4.jpg
HAT signals, GbE, USB, HDMI, etc that come out are all appropriately protected or conditioned to meet EMI requirements per product spec. All of this is TRL9.