NROL-25: search TLE; heads-up for N. American observers

From: Ted Molczan (ssl3molcz@rogers.com)
Date: Mon Apr 02 2012 - 23:21:53 UTC

  • Next message: Bram Dorreman: "PPASobs 4160 (BD) 2012-03-21"

    As I write, the launch remains scheduled for 2012 Apr 03 at 23:12 UTC:
    
    http://www.spaceflightnow.com/delta/d359/status.html
    
    Here are revised search elements:
    
    1 79701U          12095.08636530  .00000000  00000-0  00000-0 0    05
    2 79701 122.9931 217.2383 0008524  77.8521 282.3398 13.49540846    07
    
    The delays have resulted in an opportunity for visual observers in the northeast of North America to see the spacecraft
    and possibly its 2nd stage soon after the circularization burn, on a pass that would have occurred in daylight or bright
    twilight based on the earlier launch times.
    
    After SECO1, the spacecraft will be near the perigee of a roughly 200 x 1100 km orbit, inclined 123 deg. Circularization
    occurs at apogee, at very roughly 00:30 UTC (Apr 04). The spacecraft will be over the North Atlantic, headed northwest
    toward N. America. By 00:40 UTC (8:40 PM EDT on Apr 03), it will rise for observers along the northeast coast.
    Spacecraft separation may already have occurred; if not, it almost certainly will occur during this pass, since the 2nd
    stage is to be de-orbited less than an hour later, to impact in the Indian Ocean southwest of Australia.
    
    The sky will be reasonably dark along the northeast coast, but still somewhat bright further inland (e.g. western
    Ontario and Ohio), but probably still observable.
    
    The payload is unlikely to be brighter than about mag 5; the rocket may be visible to the unaided eye, but binoculars
    are recommended, and may be necessary to resolve both objects, depending on the timing and speed with which they
    separate.
    
    The search elements could easily be off in time by several minutes, and the predicted track by at least one degree.
    
    Positional observations would be helpful in confirming and refining the search elements. Descriptions of the relative
    positions and optical characteristics of both objects would be of interest, as would still and motion imagery.
    
    This will be the first of several passes visible from N. America, but the only one on which the 2nd stage is expected to
    be seen.
    
    Please see my initial report for visibility windows and other information and comments.
    
    http://satobs.org/seesat/Mar-2012/0179.html
    
    Ted Molczan
    
    
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