According to this Motherboard article [1] from Jan 27, 2018, only the Tempe, AZ gateway handles non-military traffic, with the US DOD and Russia operating the two other (military) gateways. I can't remember if the other gateways were shutdown during Iridium's bankruptcy.

[1] https://motherboard.vice.com/en_us/article/d34bmk/iridium-ne...