Companion - MRoboSub/mrobosub GitHub Wiki
The Jetson needs to be able to SSH into the companion Pi without a password in order to remotely launch mavros.
Here is a good guide on setting this up: https://www.strongdm.com/blog/ssh-passwordless-login
TLDR:
Create SSH key pair on the Jetson.
On the Jetson, run the following command to copy the public key to the Pi:
ssh-copy-id [email protected]