RE: Shuttle launch-UK observation
Date: Wed Oct 02 2002 - 13:55:44 EDT
Next message: Sebastian Stabroth: "RE: Shuttle launch-UK observation"
The launch time prediction was calculated
from the latest Twoline
Orbital Elements set. The calculation is based on the time when the
Earth's rotation carries the launch site through the orbit plane, and an
adjustment to allow for the climb to orbit.
Using a constant daily increment to
calculate the time is a good basic
method over a few days but but there are many variables to account
for, including variations in orbital parameters and the effects of orbit
With the new delay to October 7, the
launch time computes as 19:44
GMT. This may still not produce visibility over the UK.
As far as I can tell, launch time
is normally set for the middle of the
launch window (usually about ten minutes in duration). The reason for
this is to use the most efficient ascent trajectory. Going early or late
involves a dog-leg manoeuvre. The actual lift-off time can be varied on
the day - STS-105, for example, was launched 5 min early to avoid
On 2 Oct 2002 at 9:51, Bill Mitchell
> > Predicted
time for the middle of the launch window for STS-111, based
> > on the most
recent ISS element set:
> > October
3 21:19 GMT
> How do you do
> Subtracting 23
mins. 42 secs. each day since last launch I get 22:02:04 GMT.
On 2 Oct 2002 at 7:22, Dale Ireland
> Don't they usually
set the time for the start of the 10 minute launch
> window? Or the
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: Wed Oct 02 2002 - 14:09:41 EDT