Re: Question about shuttle lauunch windows to Iss

From: Edward S Light (
Date: Thu Mar 28 2002 - 07:42:12 EST

  • Next message: Jonathan T Wojack: "Re: Shenzhou III and rocket TLE's"

    Colin Knight recently asked ...
    > Can someone help clarify the criteria for shuttle launches to the Iss please.
    > As I understand it the shuttle launches within a few minutes of the time
    > that the Iss passes within the orbital plane of the launch pad.
    Not true; what you presumably meant to say was that the launch occurs near
    the times when the launch pad passes through the orbital plane of ISS.
    > Fair enough - now I've gotten hold of the map coordinates for the launch pads and just for interests sake put them into my tracking programme to work out the preferred time for next weeks launch (which everyone knows has been publicised for months.)
    > Now the Iss passes over the launch pad six times in any 24hr period so how come Nasa picks the 22:14 UTC window as the preferred launch time and not one of the other windows?  That particular window has the highest elevation of the lot so I'm wondering if this has something to do with it.
    > Can anyone comment please?
    At any location (within about 51.6 degrees of the equator), the ISS orbital
    plane passes by twice each day (strictly, twice every 23 hours 36.4 minutes
    because of the orbital plane's precession) - once heading northward, once
    heading southward. For various logistic/political/safety reasons, the
    shuttle launches along the northward part of the orbit plane.
    The fact that the ISS may be seen six times per day from the launch site
    is not really relevent; the important thing is for the shuttle to be
    in the target satellite's orbital plane.
    Clear and dark skies!
       Ed Light
    Unsubscribe from SeeSat-L by sending a message with 'unsubscribe'
    in the SUBJECT to

    This archive was generated by hypermail 2b29 : Thu Mar 28 2002 - 07:42:37 EST