Re: Atlantic SLBM Test Launches

From: Marco Langbroek (
Date: Wed Sep 25 2013 - 19:41:13 UTC

  • Next message: Marco Langbroek: "CORRECTION on Re: Atlantic SLBM Test Launches"

    Op 24-9-2013 23:21, Jonathan McDowell schreef:
    > I don't buy that the events seen were early stage ignitions - I
    > believe the launch was much nearer Florida and
    > the brightenings and clouds were associated with MIRV bus burns and
    > reentry vehicle releases during the descending phase.
    You are right. I did  some calculations, this time taking earth curvature into 
    account (I should have done that right away, with these horizontal distances).
    I went from the assumption that the major axis of the polygon from Ted's 
    Broadcast Warning exclusion zone in the S-Atlantic 
    ( was indicative of the launch 
    trajectory azimuth.
    Next I determined where the sightline azimuths from Jan Hattenbach's imagery 
    crossed this trajectory line, providing distances.
    For the two points in question where something seems to "ignite" (sudden trail 
    brightening, followed by expanding cloud) at 21:17:08 and 21:18:43 UT, I 
    calculated that:
    a) Horizontal distances are approximately 2375 resp. 2240 km (in azimuth 264.7 
    resp. 259.9);
    b) the object needs to be at an altitude of at least 380 km resp. 335 km above 
    sealevel to clear the horizon as seen at 2300 meter from La Palma;
    c) from the determined altitudes (determined from the measured RA/DEC) in 
    degrees above the horizon at these moments, the aproximate altitudes of the 
    missile above sealevel at these moments are 450 km resp. 680 km;
    d) positions are approximately 24.725 N/41.385 W resp. 23.477 N/39.537 W at 
    these points in the trajectory.
    Note: this all goes from the assumption that the direction of the major axis of 
    the oblong exclusion zone in the S-Atlantic found by Ted, determines the 
    trajectory azimuth. It also assumes my math is correct....
    Point (b) shows that these two moments hence indeed are probably NOT the 2nd and 
    3rd stage ignition as I initially (and hence erroneously) interpreted them, as 
    these reportedly happen at 70 km and 150 km altitude with the Trident (much 
    lower than the altitudes I now calculate).
    I am doing this calculation for more measured points over the trajectory 
    currently, but this takes some time.
    - Marco
    Dr Marco Langbroek  -  SatTrackCam Leiden, the Netherlands.
    Cospar 4353 (Leiden):   52.15412 N, 4.49081 E (WGS84), +0 m ASL
    Cospar 4354 (De Wilck): 52.11685 N, 4.56016 E (WGS84), -2 m ASL
    Station (b)log:
    Twitter: @Marco_Langbroek
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