"Sunsite News" jntATthomsen.mail.dk wrote in message
...

Not quite right, the launch window is actually close to 10 minutes, and
Nasa aims to launch in the middle of the window, which leaves about 5
minutes after preferred launch time which is 10.39 - but the actual launch
window opens at 10.34. The reason they wait 5 minutes is to make
everything as close to optimum as possible.

During the t-9 hold they can adjust to go anytime during the 10 minute
window, depending on the latest ISS state vector.