As you mentioned elsewhere it’s encrypted.

Take a look at /etc/crypttab and creating and adding a key file that can unlock the drive.

Essentially your additional SSD will have both a password and a file containing a password that can unlock the drive. When you unlock your root filesystem (I’m guessing at boot) it will then have the key file that can unlock the SSD.

Something like cryptsetup luksAddKey /dev/pathtossd --new-keyfile /etc/newpassword

Systemd might make this easier to setup nowadays.

Edit: Also, yes, the password to unlock your SSD is just sitting in a file in your root drive. Be sure to restrict it to only be readable by root.

I agree, but it’s more common than you’d think.

I used to work at an organization that used Chromebooks, which replaces the caps lock key with a search key (same shape, different behaviour). I was surprised at the number of people who struggled with their passwords because they would hit the “search” key, enter a single letter, and then hit “search” again. It took me a little while to figure it out because… Who does that?