Hypothetical Attacks

Denial of service

Jam uplink
White noise at frequency. Requires directed antenna.

Overpower uplink
(Captain Midnight HBO attack). Can be done with transportable. Power limited. Uplink equipment now contains ID coding.

Jam downlink
Requires very low power. Difficult to detect, especially if intermittent.

Orbital positioning

Ranging transponder spoofing
Multiple ground stations triangulate satellite position using a series of tones sent to a transponder. Ground stations observe phase differentials. Ground or airborne spoofer could transmit false responses, resulting in incorrect orbit determination.

Direct commanding
Preparation and delivery of telecommand queue.

Command replay
Record outbound telecommmand queue from TT&C facility. Replay later to initiate duplicate action.

Insertion after confirmation but prior to execution
OC formulates telecommand queue and sends to TT&C. TT&C uplinks and receives readback, which it returns to OC. If readback is correct, IOC waits for proper time to execute. Channel is vulnerable to update during this period - new telecommand queue may be uploaded prior to authenticated execute.

Takeover of spare Inmarsat (AOR East and West, POR, IOR)

Spare satellites are not always tracked by TT&C. "Available" for movement and/or use, especially over AOR.