Pre-launch elements for VAFB Titan IV launch scheduled for 16 Aug 2000

From: Ted Molczan (molczan@home.com)
Date: Tue Aug 15 2000 - 20:50:21 PDT

  • Next message: Ted Molczan: "NRO mission patch hints at Lacrosse payload on VAFB Titan IV launch"

    A Titan IV-B is scheduled to be launched on Aug 16 at 23:45 UTC.
    
    I believe that the payload is a Lacrosse, as I explained in this earlier post:
    
    http://www2.satellite.eu.org/seesat/Aug-2000/0017.html
    
    I hope that official 2-line elements for the Titan 2nd stage will be released
    soon after launch, as they were after Lacrosse 3 was launched, but in case that
    does not happen, I have produced pre-launch elements for orbits of inclination
    57 deg and 68 deg:
    
    T-IV 2nd stage   9.8  3.0  0.0  4.8 v
    1 70001U          00230.16663982  .00000000  00000-0  00000-0 0    07
    2 70001  57.0090  47.0200 0177212 165.0881 195.5654 15.06051010    07
    
    T-IV 2nd stage   9.8  3.0  0.0  4.8 v
    1 70002U          00230.16663982  .00000000  00000-0  00000-0 0    08
    2 70002  68.0000  37.0500 0177212 169.0000 195.5000 15.06050101    05
    
    These orbits assume an on-time launch at 23:45 UTC. If the launch is delayed,
    then I will issue new elements.
    
    My guess is that the orbit will be inclined at 57 deg, but the evidence is
    sufficiently conflicting, that I believe it prudent to prepare to observe the
    68 deg orbit as well.
    
    The elements are based on Lacrosse 2 and 3, and should be accurate to within a
    few minutes of time, assuming that this mission is similar. The RAAN could be
    off by a few degrees, so the track may not be quite as precise as the time.
    
    The elements are for the Titan 2nd stage; however, the Lacrosse payload should
    trail a short distance behind it for a day or two, before it manoeuvres to its
    final orbit.
    
    Here is how Mike McCants described his observation of Lacrosse 3 and its Titan
    IV 2nd stage, soon after their launch in Oct'97:
    
    http://www2.satellite.eu.org/seesat/Oct-1997/0377.html
    
    If tomorrow's launch occurs on time, then the orbit will initially be visible
    to Southern Hemisphere observers in evening twilight. Australian observers
    should expect to see it approximately 5 hours after launch. I have not checked
    whether or not there will be a simultaneous morning twilight window.
    
    North American observers can look forward to a morning twilight observation
    window, beginning on 20 August for the 57 deg orbit, and on 19 August for the
    68 deg orbit. This window will open for progressively more northerly latitudes
    in the days that follow.
    
    The weather forecast for 16 and 17 August is more likely than not to violate
    launch constraints, so a delay may occur. If, as I suspect, the launch time is
    tied to one of the existing Lacrosse orbital planes, then the launch time would
    be progressively earlier for each day of delay.
    
    If the reference plane is that of Lacrosse 3, then the launch should occur 19
    minutes earlier for each day of delay. If the reference plane is that of
    Lacrosse 2, then the launch should be 14.4 minutes earlier for each day of
    delay.
    
    Ted Molczan
    
    
    
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