Link here The details come from a presentation at a public meeting by Amit Kshatriya, Deputy Associate Administrator of NASA’s Moon to Mars program, with this the key takeaway:
Kshatriya then expanded the discussion beyond the next few Starship flights and talked about the required technologies for a fuel depot in orbit and the in-orbit capabilities needed to transfer fuel. “We need an instance of the ship that is essentially long, has the endurance to stay in orbit long enough for the sequence to work.
“So, we need a ship that has at least three to four weeks of endurance in orbit. That endurance is gained through augmented power system capability, augmented battery capacity, full insulation of the cryogenic systems, vacuum jacketing of all the lines, et cetera, to make sure that the cryogens that are being stored or are meant to be stored don’t boil off.”
The challenges of a cryogenic ship in orbit include the need to prevent boil-off from the stack. To facilitate the journey to the Moon’s surface, Starship will have to be refueled. For this, the company plans to refuel a depot in low-Earth orbit (LEO), which would be resupplied by several tanker Starships. The HLS Starship would then dock with this depot before departing for the Moon.
To prove this system will require a Starship test flight that lasts several weeks in orbit, to prove the capability needed for a lunar mission. It will also require a refueling mission that will require several Starship/Superheavy launches, one to put the fuel depot into orbit, several more to fuel that depot, and a final launch of Starship for its refueling and endurance test.
According to the update, SpaceX is still aiming to be ready of the upcoming fourth Superheavy/Starship demo orbital flight in the first two weeks. The NASA official claimed it would occur no later than the end of May. I see that as a confirmation that NASA really doesn’t expect the FAA to issue a launch permit when SpaceX is ready, and that the permit might not arrive in time for a May launch. This statement is meant to soften the blow when the launch finally gets delayed into June, or later.
Whether the many required later Starship launches as described above can get FAA approval quick enough to prove out this system soon enough to meet NASA’s 2026 present target date for its manned lunar landing seems very unlikely. Moreover, even if it does it will be a major challenge for SpaceX to meet this schedule.