On Thursday, Alain Fournier exclaimed wildly:
On Mar/11/2021 at 14:32, JF Mezei wrote :
Another question:

Say you have decided your expedition will land at the equivalent of
Greenwich on mars (0" longitude, 51° latitude N).

How difficult is it to send multiple ships to that precise location so
they land within walking distance from each other?

Since Mars rotates, and since we're talking about a direct entry from
your transit velocity vector doesn't that require that you arrive at
atmosphere entry at a time where your destination (Greenwich) has
rotated to be directly in your path?

Is this accomplished with long term micro adjustements is speed for the
whole transit so you arrive at the right time, or is transit speed
pretty much precisely fixed due to orbital mechanics and you need to so
a more significan speed adjustment as you near Mars to let Mars rotate a
bit more or less so you have your target in your path ?

Just curious on how much flexibility a fleet of Starships bringling
supplies would have in terms of departing Earth and landing all at the
same spot.

Not a major issue. You make small adjustments when still far away from Mars
to get at the right place at the right time. Even if you just want to reach
Mars anywhere, you still do mid-course corrections because aiming for Mars
from Earth would require to much precision without corrections.

The fact that you want to adjust for the exact location (and therefore time
of arrival) only slightly complicates the computations for your mid-course
corrections.


And Perry was targeted pretty precisely, so the calculations are well
understood in practice as well as in theory.

/dps

--
"What do you think of my cart, Miss Morland? A neat one, is not it?
Well hung: curricle-hung in fact. Come sit by me and we'll test the
springs."
(Speculative fiction by H.Lacedaemonian.)