Storage lifetime considerations for electronics
EEPROM Data degredation


My first call here would be to move to a EPROM, even without a window. They're much more sturdy than EEPROM or flash. Failing that, see if you can get one of Atmel's space grade EEPROMs, which will likely be more resistant to all sorts of things.


  Electrolytic capacitor lifetime


Start with a good capacitor in the first place, Nichicon or Panasonic. Or use a polymer electrolytic, but that will require soldering.


  Communication standard obsolescence


Logic level UART. 9600 or 115200 bps, 8 data bits, no parity bit, 1 stop bit. You'll be able to talk to it almost forever.