SpaceX recently published a whitepaper to describe at a high level the security measures adopted in its Starlink satellite system.
Some notable security measures:
Secure boot A technique to cryptographically verify every layer of software before running it. This ensures that only Spacex software is running on satellite, user terminals and all other components of the system.
Software updates An over the air and reliable update system ensures that new software features, fixes and patches to security vulnerabilities are deployed weekly on the entire fleet which count more than a million devices. New vulnerabilities can be patched in the field quickly.
Identity Management Each user terminal device is uniquely identified via digitally signed certificates created at manufacturing time making them difficult to be forged. Hardware-based secure key storage ensure that the keys are difficult to copy by an attacker out of the device.
Least privilege Starlink user terminals are treated as untrusted devices as they are not in contorl of SpaceX, so only minimal necessary information and functions are exposed to them.
Bug bounty program Security researchers are allowed to conduct testing and Spacex provides monetary rewards when vulnerabilities are found and reported.
That was the result of an interesting talk at DEFCON 2022 by Lennert Wouters titled “Glitched on Earth by Humans: A Black-Box Security Evaluation of the SpaceX Starlink User Terminal”
The presentation is very explicative on the general Starlkink system design and details of the user terminals:
Wouters was able after after tearing down the antenna to bypass the secure boot function, creating his own modchip based on a raspberry Pi design.
Here a link to the video demonstration of the hack Video
If you are interested in knowing more about the technology behind Starlink, I am sure you will enjoy browsing StarlinkEngineering on Reddit https://www.reddit.com/r/StarlinkEngineering/