> A satellite of that age would have used a very simple analog repeater or linear transponder, meaning that there is no communications logic occurring on the satellite.

It's broadcasting telemetry, isn't there a chance it also accepts commands?

> Military satellites launched into the '80s continued to use analogue transponders and, to some extent to this day, see unauthorized use. The only real deterrent was the difficulty of obtaining inexpensive equipment for satellite bands but the widespread use of DVB and VSATs changed that during the '90s and '00s.

WIRED had an article about this awhile back: https://www.wired.com/2009/04/fleetcom/