As you will have already found out the Raspberry Pi (the computer at the heart of the ISS-Above) does not come with an on-off switch.
Just like any computer – they don’t like it when the power is just pulled from them without doing an orderly shutdown.
If the power is lost suddenly this can (sometimes) corrupt the SD card containing the ISS-Above code).
The best solution is to clone / backup the SD card to your computer. This will allow you to quickly restore the setup to your SD Card if it ever gets corrupted. This will only take 10 minutes and is HIGHLY recommended (otherwise tears and upset might be in your future).
If you have a windows based computer follow these instructions.
If you have a Mac use these instructions.