[anonymousiam]

The S-band uplinks are not typically used during operations. They're mostly used during transfer orbit operations and initial testing, and in emergencies when something goes wrong with the normal comms (safe mode). The S-band antennas on the satellite are typically omnidirectional, so they'll hear anything strong enough to overcome the noise floor. Those comms can be encrypted or in the clear, depending upon the situation. The military satellites that I'm familiar with stop listening to the S-band uplink when their normal uplink is operational, so interference shouldn't be an issue during normal operations.

I'm not involved in this stuff anymore (now retired), but it's possible that the Starshield constellation supports transmitting on S-band (or L-Band) as a means to relay SGLS communications to satellites that are out-of-view. Having this capability would greatly benefit the workflow of transfer orbit operations and initial testing, by eliminating the constraint that the satellite must be in-view to communicate with it. It would also benefit anomaly resolution by allowing instant access to a malfunctioning spacecraft.

https://en.wikipedia.org/wiki/Satellite_Control_Network

https://www.orbitalfocus.uk/Frequencies/FrequenciesSGLS.php

https://www.af.mil/News/Article-Display/Article/473264/af-sp...

[stinkbeetle]

> I'm not involved in this stuff anymore (now retired), but it's possible that the Starshield constellation supports transmitting on S-band (or L-Band) as a means to relay SGLS communications to satellites that are out-of-view. Having this capability would greatly benefit the workflow of transfer orbit operations and initial testing, by eliminating the constraint that the satellite must be in-view to communicate with it. It would also benefit anomaly resolution by allowing instant access to a malfunctioning spacecraft.

That's interesting, thank you for the great comment. Would that kind of usage then not be counter to the standards, as suggested in the article?

[anonymousiam]

Any sort of innovation may counter "standards", but without knowing the specific ITU terms for S-band, I can't say whether or not any regulation has been violated.

The fact that somebody saw something pointed at Earth on a frequency generally reserved for uplinks doesn't necessarily mean that it would interfere with other spacecraft receiving the signals from the ground. Starlink (and presumably Starshield) operates in LEO, below most other LEO spacecraft. Maybe they're using a dish or even a phased array antenna, and pointing down instead of up. If so, the probability of interference is low.