On Mon, 12 Mar 2012 10:29:41 -0700 (PDT), Nehmo <
neh...@hotmail.com>
wrote:
Not according to these from NASA.
http://www.nasa.gov/centers/kennedy/launchingrockets/launchwindows.html
Aiming for an Open Window
02.23.12
Why does NASA sometimes schedule a rocket launch for the middle of
the night, or aim for a liftoff time when weather is notoriously
unlikely to cooperate?
The simplicity of the question belies the complexity of the answer.
The best time to start a mission is based on a blend of factors: the
flight's target and goals, the needs of the spacecraft, the type of
rocket, and the desired trajectory, which refers to the path the
vehicle and spacecraft must take to successfully start the mission.
Not only do these variables influence the preferred launch time --
the ideal time of departure -- but the overall length of the launch
window, which can vary from one second to several hours.
http://history.nasa.gov/afj/launchwindow/lw1.html
Apollo lunar landing launch window: The controlling factors and
constraints
....
When launching to land on the moon there are two fixed parameters.
The location of the launch site ... and the landing site you are
aiming for on the moon. To arrive at this landing site with the
right lighting conditions for the descent and approach a journey
must be planned that meets the various constraints that affected the
Apollo lunar mission planning, primarily in the form of trajectory
shaping and the limitation of launch opportunities, known as launch
windows.
Trajectory geometry constraints and spacecraft performance
capabilities combined to limit the accessible area on the moon.
These accessible landing area limitations combined with operational
constraints to limit launch opportunities to certain specific
periods.
....
--
Peter Duncanson, UK
(in alt.english.usage)