Whether Starship IFT-2 flies on Saturday morning or is held another few days or a week isn't really important. What's important is that it needs to be a successful test. The booster needs to burn for the full required time, the hot-staging needs to work, Starship needs to achieve its intended trajectory and it needs to splash down in the Pacific as intended.
Why? Simply that for the HLS or Human Landing System version of Starship to work is going to take nearly 20 successful missions and that says launches have to be routine.
In a presentation at a meeting of the NASA Advisory Council’s human exploration and operations committee Nov. 17, Lakiesha Hawkins, assistant deputy associate administrator in NASA’s Moon to Mars Program Office, said the company will have to perform Starship launches from both its current pad in Texas and one it is constructing at the Kennedy Space Center in order send a lander to the moon for Artemis 3.
SpaceX’s concept of operations for the Starship lunar lander it is developing for the Human Landing System (HLS) program requires multiple launches of the Starship/Super Heavy system. One launch will place a propellant depot into orbit, followed by multiple other launches of tanker versions of Starship, transferring methane and liquid oxygen propellants into the depot. That will be followed by the lander version of Starship, which will rendezvous with the depot and fill its tanks before going to the moon.
Much like Starship itself, there are simulations of what it takes to do the sort of operation this entails but - here's the key point - it has never been done before by anyone. SpaceX has shown Concept Of Operations documents for the Human Landing System (HLS) program that talk about multiple launches of the Starship/Super Heavy system. One launch will place a propellant depot into orbit. There have been reports or speculation that was the purpose for Ship 26 which had no thermal tiles or "flings" (control surfaces) - they're not needed if doesn't come back down - but S26 now appears to be obsoleted and in the "rocket garden" at Boca Chica. Whatever that propellant depot looks like, the launch will require multiple other launches of tanker versions of Starship which transfer methane and liquid oxygen propellants into the depot. That will be followed by the HLS version of Starship, which will rendezvous with the depot and fill its tanks before going to the moon.
Again, while a large number of people can cite concerns about things like fuel
evaporation and leakage on orbit, nobody has hard test data they're dropping
Exactly how many launches will be required has been a point of debate since Starship’s selection by NASA for the first HLS award in 2021. Neither NASA nor SpaceX have given firm numbers recently. A paper about the HLS program presented at the 2023 International Astronautical Congress by NASA, for example, mentioned only “a series of reusable tanker Starship variants” that would be launched to fill the depot before the Starship lander is launched, without giving a number.
Assistant deputy associate administrator Hawkins has said, “It’s in the high teens in the number of launches. In order to be able to meet the schedule that is required, as well as managing boiloff and so forth of the fuel, there’s going to need to be a rapid succession of launches of fuel.”
For additional perspective, the Government Accountability Office, in its rejection of protests by Blue Origin and Dynetics of the Starship HLS award in 2021, noted that SpaceX required 16 launches overall for a Starship lunar lander mission. Elon Musk disagreed, calling the need for 16 launches “extremely unlikely” in an August 2021 Twitter (before it was X) post. He said a “max of 8” tanker launches should be needed to fuel the Starship lander, adding it could be as few as four.
Between four and 20 launches? They'd better be more like Falcon 9's
cadence of one every three days than the seven months between the first flight
test and this one. Seven months delay times 20 launches isn't a nice
number. One month between each of 20 launches isn't that nice, either.