Here is what SpaceX has to develop/test for Artemis III -
Launch a storage depot to Earth orbit (using Starship).
Launch 10+ tankers with propellant to the storage depot (using Starship).
Launch Starship human landing system (HLS) (using another Starship).
Refuel in earth orbit.
Travel to lunar orbit.
Transfer crew from Orion to HLS (Orion with crew launched by SLS).
Land.
Liftoff.
Transfer crew to Orion.
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