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Comment by marktangotango | Hacker News Reader

What I find odd is: when this thing is operational, passengers are supposed to ride through this "flip to land" maneuver?

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If I've already signed up to ride a large soda can filled with 4,600 metric tons of cryogenic methane and oxygen into a near-perfect vacuum, only to re-enter the atmosphere at orbital velocity, I suppose I could deal with a flip maneuver.

I think the suicide burn will be dropped for passenger flights, but the flip is an integral part of the braking maneuver.

What would they replace it with?

Seems like there are two different things here; launching passengers and freight, and returning passengers in comfort and without neck injuries. One could easily envision a passenger only winged glider similar to the space shuttle to serve the passenger return role. Indeed, although spacex has nothing like that planned, these BFRs enable damn near anything.

Maybe some gyroscopic passenger seats that stay in one position relative to the ground so that they only feel g's going in one direction instead of being rag dolls.

The atmosphere on Mars is not as thick as ours so there might be an issue with that winged glider vision. And then there is the moon...

Both have much weaker gravity though.

But that doesn’t help when you have zero atmosphere. Zero times anything is still zero. And doesn’t help enough when the atmosphere is too thin.

I'd advocate for doing the flip on three engines for the added redundancy, then hovering for a second or so before landing; at least for passenger flights.

I think the idea is that two is redundant for the final design, but these test articles don't have the high power maneuvering thrusters. Without those they need to use the backup engine to manage the rotation.

Starship won't suicide burn. Raptor can downthrottle deeply enough to hover.

The flip will be less extreme in later designs because they will have better/larger RCS control thrusters to rotate it without involving the main engines.

Also the center of rotation can be controlled to be inside the passenger section. Add some seats that can automatically tilt 90 degrees and the forces might be barely noticable.

Well apparently they’re looking into ways to catch the rocket with a landing arm looking platform. Really I think they need to get those engines to fire in any circumstance. But with N=2 it’s hard to know anything.

The catching arm is for the first stage, IIRC

Second stage has always been about that flip, be it on the Moon, Mars or Earth

No flipping on the Moon since it provides no advantage there (No aerobraking)

That's a very good point. Looks like my brain also had a major malfunction ;)

That's for the booster. The goal is to skip landing legs for the booster, as it'll only operate around Earth, so it's "easy" to build infrastructure instead.

Starship (the 2nd stage) will always do that flip & land on legs, as it also needs to do it on Mars.

They sure are!

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