What if they do a full 360 degree orbit but by that time earth has already rotated 22.5 degrees further so they didn't circumnavigate around the earth? :D

They'd probably try to go back to the launch site anyway so I think it won't come up

@Mqrius If they can't get permission to deorbit to Boca Chica, I suppose a flight from Boca Chica going east to just off the West coast of Mexico/California is possible and might be a full 360 degrees relative to Earth's centre but that is not a circumnavigation so won't count. I can't see them going West for first full orbit due to orbital launch mounts positions.

If they launch from Boca Chica more East launch mount and tower and return to more West tower or anywhere in gulf of Mexico, this will count as a circumnavigation. (This is within de minimis limits.)

I think several orbits seems more likely than very close to one so I agree on doubting it will be an issue.

@ChristopherRandles FWIW I think it is best to define an orbit to be a full 360° in the nonrotating frame. In the frame rotating with the earth, orbits aren't even circular/ellipses unless they're equatorial, what axis are we measuring the rotation angle with respect to?

If you want to say the relevant axis is earth's rotation axis and thereby declare that the landing site must be further eastwards than that launch site for it to count, then that is unambiguous, but would be a silly criterion for e.g. a polar trajectory which could go around a closed circle ten times without satisfying that criterion.

Or if you had a westwards launch, the landing site being further to the west of the launch site is possible even for trajectories that did not quite reach orbital velocity.

Defining orbits in terms of ground position is just not a good idea generally - a full 360° is a well-defined thing in the nonrotating frame.

With these criteria Yuri Gagarin never reached orbit.

@Berg I think he did! Gagarin's trajectory comprised more than 360° of a circle, so if that's the criteria, I think it would count under that definition.

@Berg They have already done suborbital and I wanted it to be clear that repeating that wouldn't be a new milestone and shouldn't count.

For reuse a Starship, how much Theseusing counts? If they recover one, slap on an entirely new heat shield, entirely new engines, and new flaps, does that still count?

@Mqrius Hmm. Any one of those three and it would still count.

All three of those and I am beginning to wonder if this is more like reuse of parts rather than the whole ship. We might not know if parts reused if the ship is disassembled so I think I am inclined to say if the structure of what remains after removing heat shield, engines and flaps is disassembled (as opposed to replacing/upgrading internal parts which is fine) then it cannot be counted as reuse of a starship / SH it could only be reuse of parts which will not count.

So with this interpretation, removing and replacing all three and some internal parts would still count as reuse.

Does that seem reasonable or does anyone want to object or argue for something different?

@ChristopherRandles sounds alright to me. I'm in favor of making markets easily decidable as much as possible.