regarding 2: The robustness to physical shock isn't particularly relevant once deployed, but during launch the hardware is subjected to huge vibration and g for

regarding 2: The robustness to physical shock isn't particularly relevant once deployed, but during launch the hardware is subjected to huge vibration and g forces. If the hardware is not well assembled, parts will come off. This poses a risk to the cubesat as well as the launch vehicle. Also, radiation hardening is statistically a long-term concern for missions. Most large satellites are designed for a minimum 5 year mission, some for 20-25 year missions (many geostationary birds). On those timescales, radiation is a significant issue. These satellites are in a low earth orbit and will be burned up in the atmosphere within a year - probably less. The chances of a single event upset are really small, and there are 3 phonesats. It takes a long time for radiation to degrade the silicon in a chip, much longer than the lifespan of these particular satellites.