Q: Will the fairing be stacked by the 28th?
@elonmusk:
Yes. There’s a huge amount of hardware in the tip of the faring that being integrated on the ground, which is why we haven’t closed it out.
Nose tip has forward movable fins, cold gas attitude control thrusters, header tanks for landing, composite pressure vessels, several large batteries, etc. Placed up there to balance high mass of Raptors & rear fins at the bottom.
@Erdayastronaut
So it appears as two's the magic number on this beast! Makes sense. Will they tuck in on ascent when attached to super heavy? 3 landing legs was super aerodynamically unstable on ascent (full stack) and also unstable on decent when landing.
@elonmusk:
Stability is not an issue with 3
Stability is controlled by (very) rapid movement of rear & fwd fins during entry & landing, as well as ACS thrusters. The smaller leeward “fin” would simply be used as a leg.
Current analysis, which I’m not fully bought into, suggests that 2 rear fins with separate airframe-mounted legs will be lighter, so this is the plan for Mk1/Mk2
For aero control, it comes down to % of cross-sectional area moving vs not. Flexible as to whether front or rear, so long as within bounds of center of mass & pressure.
We also fire the ACS thrusters to rotate the vehicle & ignite Raptors at full gimbal angle to complete the turn.