Point to multipoint / TDMA contended access VSAT hub and CPE networks are well known for not having much security. In many setups the remote CPE modems, which are built from a fairly cheap BOM of hardware, implicitly trust the hub linecard. Have seen this with 3 different vendors' platforms.
I'd be willing to bet that this was either a malicious firmware push that was applied to the CPEs without proper authentication methods being in place, such as CPEs being able to verify a crypto key signed firmware signature, or a configuration file pushed to the CPEs that knocked them off the network with incorrect RF/channel/modulation/timing parameters.
Note that the Viasat KA-SAT terminals are at the very lower end of the market for contended access (64:1 or more) consumer/small business grade geostationary VSAT. Which is why it sort of makes sense that a lot of them were used for low data rate SCADA for wind farms and such.