What the Starship test flights are really for

Reaching orbit is the easy part to explain. Refuelling and reuse are the hard ones.

Each Starship flight is built around a small number of things that cannot be proven on the ground: how the heat shield survives re-entry, whether the ship can be caught and flown again, and whether two vehicles can transfer propellant in orbit.

That last item is the one Artemis depends on. A crewed landing needs a lander fuelled in space, so orbital propellant transfer is not a bonus capability — it is on the critical path.