The Arduino boards both have a very limited amount of RAM. For the probe to be able to save data from the instruments for an uplink, nonvolatile storage is necessary. For this function, I selected some 1 megabyte SPI flash chips from Adafruit.

Here is the vendor link: flash

Here is the datasheet: W25Q80BV

The features of this part include:

• 8 pin DIP package
• 3.3 volts (needs shifters for 5 volt usage)
• SPI interface
• 1megabyte capacity
• 4 ma power consumption

I have not yet tested this part.