Yes. You can disconnect your devices from the wifi, or you can unplug your modem (from the wall -- do not unplug from the back of the modem).
In addition to maratsade's suggestions, you can also disable the WiFi in the HughesNet modem. To do so, see "How do I manage my built in WiFi?" in this PDF. When doing so, make sure to click "Save Settings" after unchecking "SSID Enable" for each of the four radios (2.4GHz, 2.4GHz Guest, 5GHz and 5GHz Guest), individually. Basically, uncheck "SSID Enable" for the 2.4GHz radio, then click "Save Settings", then do the same for each of the other three radios.
I, personally, only keep the 2.4GHz radio enabled, as it's the one I use. I keep the other three disabled, not only because I don't use them, but also to keep others from being able to use them, as well. Then, if I want to disable the WiFi all together, I only have to disable the one radio.
@GabeUmakes a good point about "others." Not others in the household, but neighbors or passersby in cars. One easy way to discourage this is to set your devices to "not discoverable." Then when people click on their devices to see what networks are available, your network won't be on the list. I can see all my neighbors' networks come up about four houses down on either side of me (small lots). Some at least use names like "CenturyLink23456," or just the series of letters and numbers assigned when you get internet service, but others use their names, which seems like an unneccessary security risk to me. My next door neighbor, for example, has "MaryB" (not the real name) as her internet name. Not smart! Of course, always have a password that is secure. 1234 is NOT as secure password, LOL!