Definitely illegal in many jurisdictions. You must have the appropriate license to broadcast in any part of the spectrum. In some cases, licenses are transferable from the manufacturer of a device, to the user (Family Radio Service and WiFi for example), but the license must be bought/acquired somewhere in the chain. Given the potential for interference with military uses, I'd be very surprised to hear that anyone has managed to get a legitimate license to do that.

I've used this data in the past: http://earth-info.nga.mil/GandG/

I suspect the data available there shares at least some common ancestry with the stuff used in the weapons systems you refer to. Fortunately for us, they recognize it also has value for academia and industry.

OMG WHAT HAVE YOU DONE!?

Methane is a red herring... Global warming is being caused directly by all the hot air