AEHF 2 search elements

From: Ted Molczan (ssl3molcz@rogers.com)
Date: Thu May 03 2012 - 14:01:17 UTC

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    AEHF 2, the second Milstar replacement, is scheduled for launch from CCAFS, aboard an Atlas 5-531, today, 2012 May 03,
    between 18:46 UTC and 20:46 UTC:
    
    http://www.spaceflightnow.com/atlas/av031/status.html
    
    Here is the approximate MECO 2 (T+00:27:48) TLE, assuming launch at 18:46 UTC into the same initial orbit as AEHF 1
    (10039A / 36868):
    
    AHEF 2                                                 278 X 49989 km
    1 79201U          12124.80125000  .00000109  00000-0  96487-4 0    06
    2 79201  22.1675 324.6620 7887706 180.0373   1.0167  1.55234955    06
    
    Not long after spacecraft separation (T+00:51:11), the Centaur will perform a CCAM (collision and contamination
    avoidance manoeuvre) followed by blowdown of any remaining propellants, which should be complete by about 4400 s after
    separation, or about 20:50:31 UTC, which is the epoch of the search TLE, based on the observed orbit of AEHF 1's Centaur
    (10039B / 36869):
    
    Centaur                                                228 X 50238 km
    1 79202U          12124.86841435  .00012772  00000-0  43300-2 0    03
    2 79202  21.7424 326.8434 7910252 177.8438  31.3481  1.54504177    00
    
    The press kit reports inclination of "21.0 deg (optimized)". If so, both of the above inclinations are about 1 deg too
    high; RAAN probably also is a bit off. The AEHF 1 press kit provided seriously erroneous information on the inclination,
    which disinclines me to fully rely on that of AEHF 2. Let's see what more we can learn, and be prepared to revise the
    above accordingly.
    
    Based on what was learned in the aftermath of the aborted firing of AEHF 1's LAE (liquid apogee engine), three LAE
    firings are planned to be completed within 6 days of launch, which will raise the apogee to about 19,000 km, and reduce
    the inclination to about 6 deg. This will be followed by about 100 days of firing by the hall current thruster electric
    propulsion system, to reach a 4.8 deg inclined synchronous orbit. 
    
    AEHF 2 is likely to be checked out near 90 W for several months, before being moved to its operational location. Its
    coverage footprint reportedly will include Europe; therefore, we might expect to find it near 39 W, presently occupied
    by Milstar 1 (94009A / 22988); or 30 E, presently occupied by Milstar 5 (02001A / 27168). 
    
    Ted Molczan
    
    
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