It would be interesting to look at the NCDXCC HF beacons from space to get an idea of ionospheric absorption. These have predictable times and variable predictable power levels, so path losses can be easily calculated.
Monitoring the 10M frequency at 28.200 might provide useful information for future Mode A applications. With beacons all around the world, broadcasting every 3 minutes at known power levels, a 28.2 MHz receiver could provide a wealth of information. The beacons ID themselves, so data analysis should be easy; all that would be required is some sort of time tagging. I suspect that the satellite would never be out of range of a beacon.
How much data storage is available? I need to calculate how much data you would need to obtain.
It would be interesting to launch these satellites at various points in the solar cycle. - Duffey KK6MC/5