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 ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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