The Increasing Threat to Satellite Communications

By Sean Patrick Bain
Embry Riddle Aeronautical University

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The Overall Threat

The basis of concern in the interception and misuse of satellite ground link systems lies in the mechanics of its operation. In conventional satellite communication up- and downlinks, the satellite utilizes an antenna that is connected to a receiver unit and a transmitter unit, which typically are separate devices. These devices are in turn connected to the satellites’ internal Command and Data Handling system or onboard computer that operates all the other spacecraft mechanisms including the thrusters, attitude orientation detection and control, and any other onboard payloads.

In typical orbital operation, a signal is generated onboard the satellite while in orbit. This signal is a function of its mission and intent; an example would be in a typical communications satellite where a signal is received by the receiver from a transmitting ground-station, fed into the onboard computer, and relayed to the transmitter unit. The transmitter applies the signal to the antenna, which projects the signal towards another receiving ground-station
The concern involved in this process lies in the potential prevention or misuse of the communication. As was true in the medieval era, these messages are often crucial and urgent, especially communications sent over a dedicated link as may corporations and governments employ worldwide. Forces opposing these users have and will continue to use methods of disruption of the communication to gain an advantage in competition with those whom the message is actually intended to serve. The two primary means of this disruption in commerce and policy lies in two primary methodologies: preventative action and misuse.

Preventative Action

Preventative action involves the deliberate hindrances of or action taken to prevent a message from continuing to its intended destination. Typically, these measures are only employed during times of open hostilities and with the intent of eliminating an enemies’ resources. One method to accomplish this end is satellite signal jamming. Jamming involves the transmission of a large modulated carrier to the receiving terminal of a target approximating the same frequency of the signal the senders are trying to prevent, effectively flooding the receiver with a noise signal and preventing the interpretation of any target signal. Although this may be combated using sequenced modulations in a transmissions data rate, it is an effective means of preventing any signals from being received from a targeted host.

Another method employed is open offensive action. In order to best-prevent any communications interchange, a hostile force might pursue action to simply destroy either a ground-station or orbiting satellite critical to an operation. Although very few attacks on satellites have taken place in the past, advances in technology worldwide in the fields of rocketry, kinetic munitions, and particle weapons ensure that this concept will become a concern in the very near future and have a widespread effect on the nature of warfare.

Misuse

This concept typically raises greater concern than the previous due to its nature. Because its methods of execution are often passive and undetectable, they may be employed during peacetime as an effective means of gathering intelligence. These methods are considered comparable to ‘wire-tapping’, allowing the aggressor to gain information on the target and use it to an advantage.

One obvious application of this concept that has been applied since well before the invention of satellite communications is in bribed cooperation of a component of the user, effectively ‘bribing the scribe’. This concept is applied to satellite technology in that the encryption codes employed may be broken onboard the spacecraft either by a covert informant or code breaking efforts. The end-result of the successful completion of this effort results in the hostile force gaining control of the spacecraft, its information, and capabilities.

Another method which is far less expensive and tasking that the one previously described is ground-based signal interception. This method relies on a relatively widespread signal transmission from the target spacecraft in orbit. Upon transmission of the signal, usually predictable as a function of position and time, a hostile force would employ a small ground-station or listening post within the range of communication. Although it is completely reliant on the user’s employment of the communication, this is an effective and undetectable means of gathering intelligence and advantage against the selected target. This method served as the basis of the following research experiment briefly reviewed in the following section of this document in an attempt to employ a similar mechanism and intercept open-source satellite data.