When SpaceX first successfully transfers propellant between two separate Starship vehicles in Earth orbit

My median prediction for the first successful propellant transfer is 20th February 2028 because SpaceX's repeated demonstration delays—from March 2025 to March 2026 and beyond—signal complex unfinished technical prerequisites.

The event occurs when SpaceX publicly demonstrates transfer of propellant from one Starship vehicle to a different Starship vehicle while both vehicles are in Earth orbit, and the transfer is reported as successful. The transfer must be ship-to-ship, not tank-to-tank within a single vehicle, and not between a Starship and another spacecraft type. A ground test, suborbital test, simulation, docking only, or any transfer attempt that is not publicly described as successful does not count. If multiple in-orbit transfers occur, the first successful one is the resolution event.