They also obtain funding from mineral development leases. I don't believe such revenue is more than a token used to assert ownership.
If Congress wished to obtain serious revenue from mineral development, they would open all federal lands to entry and development, and IMHO, they would also license development of outer space resorces. Of course all that would encourage explosive development and growth of the economy, which is apparently not a good thing.
Are you aware that Alaska tax law exempts materials and supplies for use on a vehicle with orbital or extraterrestrial flight capabilities from any local sales tax?