NROL-32 search elements

From: Ted Molczan (
Date: Sat Nov 13 2010 - 15:31:37 UTC

  • Next message: Bill Arnold: "Obs from Nov. 12"

    NROL-32 is scheduled for launch on a Delta IV-Heavy, from Cape Canaveral, on 2010 Nov 18, at 23:10
    UTC, the opening of a launch window of several hours duration.
    I believe the payload is the fifth in the series of what we call Mentor spacecraft, aka Advanced
    Orion, which gather signals intelligence from inclined geosynchronous orbits. They are among the
    largest satellites ever deployed, with a main antenna generally believed to span ~100 m.
    I offer the following search elements, which should be considered to be very approximate. They are
    based on launch at 23:10 UTC.
    1. Launch and GTO
    The LEO and GTO orbits are the same as the ones I posted prior to NROL-26, rotated to the start of
    the launch window of NROL-32. Mission elapsed times are approximate.
    LEO park T+00:12:48 to T+00:20:30                        259 X 272 km
    1 78901U          10322.98275464  .00000000  00000-0  00000-0 0    01
    2 78901  27.2800 223.3769 0010000 183.0000 359.3500 16.05000000    08
    GTO T+00:28:30 to T+05:24:30                           278 X 36398 km
    1 78902U          10323.19115508  .00000000  00000-0  00000-0 0    08
    2 78902  27.2800 223.2969 7307000 182.9000 167.5000  2.23480000    05
    2. GEO Insertion
    The ~3 min burn to insert into GEO will occur about 5h24m after launch, near the first ascending
    node and apogee of the GTO, near 96 E. I believe that the payload's initial inclination will be
    between 5 and 7 deg, and have adopted 6 deg as my guess. The 78903 elset is derived from that of
    Mentor 4, which initially drifted westward, at nearly 0.5 deg/d.
    Payload GEO - westward drift                         35705 X 35943 km
    1 78903U          10323.19652778  .00000000  00000-0  00000-0 0    04
    2 78903   6.0000 222.9192 0028124 186.2394 175.8683  1.00142488    08
    In the event that the payload drifts eastward at the same rate, its orbit could be something like
    Payload GEO - eastward drift                         35557 X 35944 km
    1 78904U          10323.19652779  .00000000  00000-0  00000-0 0    06
    2 78904   6.0000 222.9192 0046000 186.2394 175.8683  1.00405000    04
    3. CCAM and Propellant Dump
    About 10 min after the GEO insertion manoeuvre, the now separated 2nd stage will perform the CCAM
    (contamination and collision avoidance manoeuvre), followed shortly by the propellant dump,
    resulting in approximately the following orbit, which is derived from that of NROL-26.
    Delta IV 5 m 2nd stage                               35940 X 38084 km
    1 78905U          10323.22430556  .00000000  00000-0  00000-0 0    08
    2 78905   6.0000 219.6655 0247122  13.9414   1.8017  0.96057559    04
    Since the inclination change at GEO insertion would be less than that of NROL-26, there may be
    additional propellant to dispose of, which could result in some combination of lower RAAN and
    greater apogee, which I have not attempted to estimate.
    4. Visibility Prospects
    The launch phase will be an entirely Eastern Hemisphere show, but there won't be much to see, due to
    daylight. Depending on the time of launch, the GTO may be briefly visible from South Africa,
    beginning about half an hour after launch. 
    GEO insertion will occur ~36000 km over the equator near 96 E, but it will be day-time over that
    hemisphere, so I doubt anyone will see the rocket burns or cloud formed by the propellant dump, but
    I will leave it to prospective observers in adjacent areas to evaluate potential visibility, bearing
    in mind that the launch could occur up to several hours later than the launch time used as the basis
    for the above elements.
    On the nights following the launch, the payload and its upper stage may be found near the above
    orbits. I do not know the payload's destination, but would not be surprised if it heads east, to
    replace Mentor 1 (95022A / 23567), located at 127 E (as of the latest elements, on 2010 Jan 01). In
    that case, it may be near the 78904 orbit, visible from Asia and Australia. If it heads west, the
    78903 orbit puts it initially within range of Asia and Australia, and South Africa by the second
    week of December.
    Mentor is by far the brightest satellite in GEO, normally reaching magnitude 8 - without benefit of
    flaring due to favourable sun angle. The brightness of Mentor was discussed here recently:
    The upper stage should drift within range of Eastern Europe and South Africa by the night following
    launch, and within range of Western Europe a couple of nights after that. It will reach mag 10-11,
    when well placed for observation.
    Happy hunting!
    Ted Molczan
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