June 2025. SpaceX has completed its fourth orbital refueling demonstration. Starship HLS requires approximately 16 tanker flights to fully fuel a single lunar-bound vehicle in low Earth orbit. That is the critical bottleneck. Every aspect of the settlement timeline hinges on refueling cadence.

Sixteen tanker flights. Let us be honest about what that means operationally. Cryogenic propellant boil-off rates for liquid oxygen and methane in LEO are on the order of 0.1 to 0.5 percent per day depending on insulation. If you cannot launch all sixteen tankers within a narrow window, you are literally losing fuel faster than you can load it.

The data from the March 2025 refueling test showed a transfer efficiency of 97.3 percent for LOX and 94.8 percent for methane. Those numbers are better than the pessimistic models predicted. SpaceX also demonstrated autonomous docking and fluid coupling in under 40 minutes. The cadence problem is a manufacturing problem, not a physics problem.

Manufacturing problem is generous. The Starship HLS variant requires a fundamentally different landing architecture than anything flown before. No landing legs in the traditional sense. The vehicle is 50 meters tall and must touch down on unimproved lunar regolith. The exhaust plume from those Raptor engines will excavate a crater meters deep. How do you land a skyscraper on gravel?

SpaceX is addressing that with the elevated engine configuration. The HLS variant moves the landing thrusters to mid-body, roughly 30 meters above the surface, firing at an angle to deflect exhaust laterally rather than directly into the ground. The December 2024 cold-flow tests at Boca Chica validated the thrust vectoring geometry. Plume impingement models show regolith displacement reduced by 85 percent compared to a base-mounted engine configuration.

Reduced by 85 percent still leaves 15 percent of a very large problem. Each Raptor 3 produces roughly 280 tons of thrust. Even lateral exhaust at lunar gravity will send regolith particles ballistic at hundreds of meters per second. Any pre-positioned equipment within a kilometer radius is at risk. The first Starship HLS landing is also the first test of whether it destroys the very infrastructure it was sent to support. That is a design tension SpaceX has not fully resolved.