How many Starship flights would it take to make Mars self-sustaining?

“With booster ultimately flying up to ~20 times per day & ship flying up to ~5 times per day. Useful load to Mars is ~150 metric tons, but requires ~5 orbital refilling tanker flights. Target: >1 megaton of cargo & people delivered to Mars, so that it becomes self-sustaining.”

— Elon Musk, 15 April 2023 · Post on X ↗