I think it's a first from a platform cybersecurity hacking perspective. Somewhat similar actions were done but not at this level

"An old satellite was hacked to broadcast signals across North America" - https://www.freethink.com/space/decommissioned-satellite-hac...

And in Brasil they have been using some US Navy satellites for years.

"The Great Brazilian Sat-Hack Crackdown" - https://www.wired.com/2009/04/fleetcom/