SpaceX Rideshare Payload User's Guide
An interesting document covering some of the requirements for hardware which is going to be sent to space.
How to download Altium templates – PCIE card, COM Express and other form factors
Altium has a lot of free templates for different form factors. For example, if you need to design a PCIE card, you don’t have to create it from scratch. You can download it and it will save you a lot of time. Here is the link to the Altium design content website: http://designcontent.live.altium.com/
