The secret of NASA budgets
nasa NEVER budgets for the full lifetime cost of anything. They budget to get it up in space for a "nominal" mission. Then, when it's up there and working, they come back and ask for more money to keep it running.
Every Mars mission has been like this. A nominal 1 month mission, then a request for more funds for the next 1 or 2 or 3 years...
I think ISS will be like this. Current funds will be ENTIRELY expended in building it. Then, when it's built, there'll be a request for more funds to OPERATE it...
(And the funding bodies have historically ALWAYS given way to this subtle variant of blackmail)
So don't worry...
