AWST: Pentagon Turns On First SBIRS Sensor

From: Ted Molczan (molczanseesat@rogers.com)
Date: Mon Nov 20 2006 - 07:42:17 EST

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    Aviation Week and Space Technology has published an article on the successful
    deployment of the first SBIRS High (Space-Based Infrared System) HEO (high
    elliptical orbit) sensor, including an impressive test image of the recent
    launch of DMSP F18 (06050A / 29522) aboard a Delta IV (4,0). The article is
    available on Aviation Now, which unfortunately has only a small version of the
    photo:
    
    http://www.aviationnow.com/avnow/news/channel_awst_story.jsp?id=news/aw112006p2.xml
    
    The Delta IV appears at the upper right of the photo. Here is a tabulation of
    USA 184 / SBIRS HEO-1's location during the first stage firing of the Delta IV,
    from lift-off on 2006 Nov 04, 13:53 UTC to MECO (main engine cut-off).
    
       UTC      Lat       Long     Altitude - km
    13:53:00  51.384 N  176.517 E   28875.261
    13:53:10  51.407 N  176.513 E   28893.891
    13:53:20  51.430 N  176.509 E   28912.501
    13:53:30  51.453 N  176.506 E   28931.090
    13:53:40  51.476 N  176.502 E   28949.659
    13:53:50  51.498 N  176.498 E   28968.208
    13:54:00  51.521 N  176.495 E   28986.736
    13:54:10  51.544 N  176.491 E   29005.245
    13:54:20  51.566 N  176.487 E   29023.732
    13:54:30  51.589 N  176.484 E   29042.200
    13:54:40  51.611 N  176.480 E   29060.648
    13:54:50  51.634 N  176.476 E   29079.075
    13:55:00  51.657 N  176.473 E   29097.482
    13:55:10  51.679 N  176.469 E   29115.869
    13:55:20  51.701 N  176.465 E   29134.235
    13:55:30  51.724 N  176.462 E   29152.582
    13:55:40  51.746 N  176.458 E   29170.908
    13:55:50  51.768 N  176.454 E   29189.215
    13:56:00  51.791 N  176.451 E   29207.501
    13:56:10  51.813 N  176.447 E   29225.767
    13:56:20  51.835 N  176.443 E   29244.013
    13:56:30  51.857 N  176.440 E   29262.239
    13:56:40  51.880 N  176.436 E   29280.445
    13:56:50  51.902 N  176.432 E   29298.630
    13:57:00  51.924 N  176.429 E   29316.796
    13:57:04  MECO
    
    The above are based upon the following elset derived from hobbyist visual
    observations:
    
    USA 184          5.0  2.0  0.0  3.7 v
    1 29249U 06027A   06311.08515391  .00000600  00000-0  11155 0 0    05
    2 29249  63.2600  29.0509 7179380 268.8455  91.1545  2.00640981    08
    
    From the vantage point of SBIRS, DMSP F18 at lift-off was near azimuth 86 deg
    (slightly north of due east), at a range of 31,600 km; by MECO, the azimuth was
    about 101 deg (11 deg south of due east), and range was about 32,900 km.
    
    Next SBIRS-HEO Launch
    
    The AWST article states, "the [HEO-1] sensor will not be handed over for
    operational use until June 2008, at which time HEO-2 should have joined HEO-1 in
    orbit." Spaceflight Now's launch schedule indicates only one launch consistent
    with this information: NROL-28, an Atlas 5-411, scheduled for 2007 Apr 3:
    
    http://www.spaceflightnow.com/tracking/index.html
    
    I estimate that Atlas 5-411 can place about 5200 kg into a Molniya orbit; the
    comparable value for the Delta IV 4,2 that launched USA 184 / NROL-22 (06027A /
    29249) is about 4900 kg, so the Atlas 5-411 is a good match. The next smaller
    Atlas 5, the 401, could place only about 4200 kg to Molniya; the next smaller
    Delta IV, the (4,0), could place about 3400 kg to Molniya, so from this it can
    be inferred that the mass of USA 184, including SBIRS-HEO, is between about 4200
    kg and 4900 kg.
    
    Identity of NRO Host
    
    AWST identifies USA 184 - HEO-1's NRO host - as a "communications relay
    payload", which I take to mean an SDS (Satellite Data System) type, used
    primarily to relay KeyHole imagery.
    
    Corroborating evidence may come from the launch of NROL-29, scheduled for late
    2008, from VAFB, on an Atlas 5-521. No clue yet as to its target orbit, but if
    it goes to Molniya, then its payload would be up to 5500 kg - quite a bit
    greater than that of the two SBIRS-HEO hosts. I expect SIGINT satellites to have
    greater mass than SDS satellites, so this eventuality would tend to support SDS
    as the mission of the SBIRS-HEO hosts. Time will tell.
    
    Ted Molczan
    
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