Fast track Soyuz is docked

On 13-03-29 08:38, Greg (Strider) Moore wrote:

What is the possible frequency of the "fast launch" ?
No more than the frequency of the previous method.

Are you saying that they can dock within the same day from launch no
matter what the distance is between Soyuz and ISS at the time Soyuz
enters orbit ?

Partly. I'm also saying the Russians don't BUILD that many Soyuz. So it
doesn't matter much if this increases frequency.
And since ISS is a lab, they want as few launches (well dockings) with as
much time between them as possible.

So increased frequency doesn't give them much.

Now, does this give them more opportunities to launch, perhaps. I don't
know the particulars of the Soyuz cross-range, but that would impact
opportunities.


I was under the impression they needed to choose launch days where the
station ends up being not too far ahead of the Soyuz once it reaches
orbit. This way, they can make up the distance (3500km for yesterday's
launch) within a small number of orbits.


That's one of many constraints. Lighting angles are another constraint.

One of the limitations is sleep. For the current launch, they opened the
hatches to the station 21 hours after they woke up that morning.

That limitation has nothing to do with the frequency.

Actually it does. If at time Soyuz enters orbit, ISS is 25,000 km ahead,
it means many extra hours are needed for Soyuz to catch up.


So they nap.

And if the crew are already strained (sleep deprived) for a 6 hour
launch-dock, can they really add many more hours of orbit without
allowing the crew to sleep ?


Sure, they just postpone a day.


So, on days where the launch window uts the Soyuz in orbit way too far
from ISS to catch up, single day may not be feasable. (unless, of
course, they get the crew to wake up much closer to launch).


Basically I think I see where you're going and it's partly accurate. i.e.
you probably want a same day docking or a 2 day docking. You don't want
something like a situation where they have to be awake for 35 hours.




--
Greg D. Moore http://greenmountainsoftware.wordpress.com/
CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net