>>1800475They learned everything they could from the sub-orbital hops they've already done. S20 is done.
The starship orbital stack is going to come off the pad very fast. Should have thrust-to-weight ratio of 1.4+ at takeoff. Reusable vehicles care more about fuel efficiency and therefore T/W than expendables because fuel is a bigger part of operational cost.
If you think in terms of cost per ton of payload to orbit, you can't cheat. ISP, T/W are nice but only if they help bring down cost to orbit (or to surface of Mars / Moon / whatever), per payload ton.
Current Mars missions have a cost/ton of payload of $1B. To make a Martian city, have to bring that < $100k/t, or 10 000 times better.
How will you catch ship with arms? Very similar to booster. Need shield tiles to go over 180° so catch points will have to pop out or reach around. Can you catch with the flaps, aiming them forward enough? That is not a problem you want to try to solve!
Forward flaps will work, but have lots of room for optimization. They are the wrong size, the wrong position, and the wrong location (not sure what the distinction between those last two is). They bug him. Could maybe get rid of them.
They will build a factory to replace the tents.
