The SpaceX Autonomous spaceport drone ships have longer and shorter direction, both for the flat, apparently land-able area, and total footprint in the water. The ships have vertical projections at the extreme ends.
There are several potentially meaningful directions in the problem, including:
- General direction of the waves; affects pitching of the ship
- General direction of the winds; affects rocket's trajectory
- Direction of rocket's return orbit, often from the West from Florida, but not necessarily so, especially from California (more polar orbits).
For landings on Mars there are elongated landing ellipses. But on Earth there is so much more live, constantly updating information available (e.g. GPS, meteorology) and of course some significant propulsive control at certain moments. Still, for Earth propulsive landing, wind direction and speed will vary along the path back to the surface and there can be gusting. I don't know if the ASDS had them, but laser doppler anemometers capable of profiling wind speed exist. When all is said and done, Is there anything like a landing ellipse for the Falcon 9?
At the time of landing, are the ASDS ships generally oriented with their longer direction parallel to the direction with the largest residual uncertainties in the landing location, or parallel to the direction of oncoming waves to minimize the amplitude of wave-induced pitching, or does it not really matter?