If I'm not mistaken, SpaceX is already contracted by NASA to do on orbit refuelling, and one of the recent starships did initial trials of fuel transmission (internal for now).

Update: - source article - $58M contract to do that - https://www.teslarati.com/spacex-starship-nasa-contract-orbi...

- chatgpt confirmation + links to more sources - https://chatgpt.com/share/e/674b5c1b-d318-8004-b79d-c0eefc59...