Well, this is my first post on SlashDot, eventhough I have been reading it for many years. I couldn't pass up the opportunity to provide some comment on this subject as it pretains directly to what I do for a living.
I have designed satellite communication systems (on the ground, and on the spacecraft) for several DOD, NASA/JPL, and commericial programs, and I have a few comments and thoughts to post on satellite security.
As to the main question, would it be time worthy? I would have to say No. It would take a significant amount of expertise and knowledge to even know where to begin, not to mention a lot of really expensive hardware.
First of all, DOD programs without a doubt are going to be encrypted. Commercial satellites as well are normally going to be encrypted. Nasa/JPL, also uses encryption, though not to the same extent, and not on "all" satellites.
But even without encryption (and we will talk about the RF in a minute), there are other factors. Commanding a satellite is not like sending an email. There is a complicated command structure which is invariably different on almost every satellite. This structure would be most definately be difficult to decipher.
Commands are also subject to onboard (satellite) logic to determine if the command is real (ie. does it make sense?, is the command sequential with other commands?, does it commence at the right time?). This is done more as a check and balance against ground operators, than "satellite" hackers, but it complicates the matter either way.
The downlink is even worse. Even "if" unenecrypted the downlinked data, will most likely use several different data rates, on multiple carrier/subcarrier configurations. The telemetry will most probably be further convolutionally or reed solomon encoded, and lets not even talk about sub-commutated telemetry options in which the format of the telemetry frame will change on some pre-defined basis.
Now, as for the RF. Can you "jam" a satellite, to perform sometype of DOS attack. Yes, if you had the proper equipment, and (here's the tricky part) could "out-RF" the people who use the satellite regularly. Lets use a commercial buisness as an example. Buisness A, has probably spent 2+ million dollars, on a 10m+ antenna to talk to their satellite. They are most likely implementing a pricey HPA (high power amplifer), sufficient to provide 30-40 dB of link margin on the uplink. I don't many ham's with access to this type of equipment.
As for the physics. Well, theres all kinds of other problems. LEO satellites for example MOVE. Theres the astro-dynamics to consider (ie. where's the satellite you want to talk to). Things like RF doppler shift and antenna pointing accuracy come to mind. Not to mention downlinks will only happen if co-located with a "real" ground station.
Geez, there's lots of other problems I dont even have time to mentions. Differences between CCSDS and SGLS, different RF bands, satellite command addressing.... Anyway I guess the bottom line is, I don't loose any sleep at night over satellite security.
Laters
J
Slashdot Mirror
Well, this is my first post on SlashDot, eventhough I have been reading it for many years. I couldn't pass up the opportunity to provide some comment on this subject as it pretains directly to what I do for a living. I have designed satellite communication systems (on the ground, and on the spacecraft) for several DOD, NASA/JPL, and commericial programs, and I have a few comments and thoughts to post on satellite security. As to the main question, would it be time worthy? I would have to say No. It would take a significant amount of expertise and knowledge to even know where to begin, not to mention a lot of really expensive hardware. First of all, DOD programs without a doubt are going to be encrypted. Commercial satellites as well are normally going to be encrypted. Nasa/JPL, also uses encryption, though not to the same extent, and not on "all" satellites. But even without encryption (and we will talk about the RF in a minute), there are other factors. Commanding a satellite is not like sending an email. There is a complicated command structure which is invariably different on almost every satellite. This structure would be most definately be difficult to decipher. Commands are also subject to onboard (satellite) logic to determine if the command is real (ie. does it make sense?, is the command sequential with other commands?, does it commence at the right time?). This is done more as a check and balance against ground operators, than "satellite" hackers, but it complicates the matter either way. The downlink is even worse. Even "if" unenecrypted the downlinked data, will most likely use several different data rates, on multiple carrier/subcarrier configurations. The telemetry will most probably be further convolutionally or reed solomon encoded, and lets not even talk about sub-commutated telemetry options in which the format of the telemetry frame will change on some pre-defined basis. Now, as for the RF. Can you "jam" a satellite, to perform sometype of DOS attack. Yes, if you had the proper equipment, and (here's the tricky part) could "out-RF" the people who use the satellite regularly. Lets use a commercial buisness as an example. Buisness A, has probably spent 2+ million dollars, on a 10m+ antenna to talk to their satellite. They are most likely implementing a pricey HPA (high power amplifer), sufficient to provide 30-40 dB of link margin on the uplink. I don't many ham's with access to this type of equipment. As for the physics. Well, theres all kinds of other problems. LEO satellites for example MOVE. Theres the astro-dynamics to consider (ie. where's the satellite you want to talk to). Things like RF doppler shift and antenna pointing accuracy come to mind. Not to mention downlinks will only happen if co-located with a "real" ground station. Geez, there's lots of other problems I dont even have time to mentions. Differences between CCSDS and SGLS, different RF bands, satellite command addressing.... Anyway I guess the bottom line is, I don't loose any sleep at night over satellite security. Laters J