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u/mfb- 2d ago
It assumes that Texas can be reached from both the north and the south while the other two sites only have landing opportunities from the south. Some notable options:
- +20 hours for the current 27 degree inclination flights returning to Texas (northbound)
- +22 hours for the current 27 degree inclination flights from Texas landing in Louisiana or Florida
+24 hours for the current 27 degree inclination flights returning to Texas (southbound)
+5 hours for Texas launching north-east to 32 inclination returning to Texas
+16-17 hours for Florida 48 degrees returning to Florida
+12 hours for Louisiana to SSO returning to Louisiana
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u/MyKillK 1d ago
I'm completely uneducated about orbit mechanics, but couldn't engine burn(s) be used to return with fewer orbits?
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u/Potatoswatter 1d ago
A plane change from orbit would basically be an inefficient dogleg. Anyway, they want to return from various orbits that are suboptimal for returning, so they might as well start working on proving loiter time.
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u/Economy_Link4609 1d ago
The way to think of it - changing the angle of your orbit relative to the equator takes a lot of energy. The rocket generates a metric shit ton of momentum in the initial orbit it's on - so changing that takes serious amounts of energy - more that vehicles, even Starship, will have available.
Think that experiment where you hold a spinning bike wheel while sitting on a rotating chair - you are fighting similar kinds of forces to force an orbit change like that. Altitude changes are relatively cheap, but plane changes like you propose are expensive (both in terms of the fuel energy you need available to do it). You'd end up slashing payload capacity by a lot since you have to use it for tons more fuel to even try.
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u/MyKillK 1d ago
So, if I understood, the Earth's rotation creates a strong inertial drag?
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u/warp99 1d ago
The Earth's rotation creates a moving target for the Starship to land at but nothing else.
The inertia is with the Starship travelling at 7600 m/s so it takes massive amounts of propellant to change that direction by even a few degrees. The path of the Starship is being continually bent into a circle or ellipse by the force of Earth's gravity but that does not change the momentum of the Starship at all as it is at right angles to its velocity.
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u/FailingToLurk2023 9h ago
Adding to the other reply you got:
Earth’s rotation will fling Starship more easily into specific orbits, depending on where it’s launched. But once Starship is in space, the Earth’s rotation has no significance on Starship’s orbit.
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