Lloyd Droppers of Project Earendel writes about various aspects of open source rocket and spacecraft development and about its benefits: Op-ed | Open Source Technology: A New Direction for Space – SpaceNews –

Open source software and hardware are rapidly decreasing the cost required to get systems up and running. A great example of this is NASA’s PhoneSat bus, which used commercial off-the-shelf parts and the Android operating system and reportedly cost only $3,500 to produce. With the use of open source software to design components and open source hardware to test components, the price of system development has the potential to be accessible to many hobbyists and small businesses.

The most important open source documentation in aerospace is probably the Defense Technical Information Center and the NASA Technical Reports Server. While not traditionally thought of as open source, many of the older technical reports (roughly pre-1980) have detailed documentation including drawings, test plans and results sufficient to duplicate the devices and test results, and are in the public domain. NASA also has released a variety of open source software packages on topics ranging from orbit determination to robot vision.