Hi all - Here's an extract from a recent issue of Jonathan's Space Report, which some of you are probably already familiar with. Since this one concerns the Iridium satellites, I thought I'd repost it: Jonathan's Space Report No. 352 1998 Mar 11 Cambridge, MA Recent Launches The five Iridium satellites launched on Feb 18 began raising their orbits to operational altitude in early March. Most of the Iridium constellation is in a 100.4 min, 774 x 780 km x 86.4 deg operational orbit to which the satellites maneuver after launch into a much lower parking orbit. However, some satellites have been placed in a reserve orbit 10-15 km lower than the operational one. One satellite was temporarily placed in a higher 785 x 790 km orbit. Of the 51 Iridium satellites launched to date, two failed and remained in parking orbit; six are currently in the reserve orbit; four were still raising their orbits from parking to operational as of March 9; and the remaining 39 satellites are in the operational orbit. Details of orbital changes for individual satellites are as follows: 1997 Jul: SV021 failed, stayed in parking orbit 1997 Sep 6: SV011 to reserve orbit since this date 1997 Sep 11: SV004 to reserve orbit for 19 days, now operational 1997 Sep: SV027 failed, stayed in parking orbit 1997 Oct: SV036 delayed 2 weeks in move from parking orbit 1997 Nov 22: SV040 deployed to reserve orbit until Jan 27 1997 Nov 23: SV038 deployed to reserve orbit, remains there 1997 Dec 11: SV020 to high reserve for 9 days, now operational 1997 Dec 20: SV018 to reserve orbit since this date 1997 Dec 23: SV042 to reserve orbit since this date 1997 Dec 27: SV026 to reserve orbit for 1 month, now operational 1998 Jan 11: SV005 to reserve orbit since this date 1998 Feb 3: SV048 to reserve orbit since this date 1998 Feb 21: SV024 drifting higher, probably will move to reserve Jonathan McDowell Harvard-Smithsonian Center for Astrophysics 60 Garden St, MS6 Cambridge MA 02138, USA phone: (617) 495-7176 jcm@urania.harvard.edu jmcdowell@cfa.harvard.edu JSR: http://hea-www.harvard.edu/~jcm/space/jsr/jsr.html Back issues: ftp://sao-ftp.harvard.edu/pub/jcm/space/news/news.* To check on the status of the constellation, I sorted the orbital elements (from Mike McCants' CS980319 set) by RA of node and by mean motion, then grouped the results. Ir Norad Int Des Epoch Node MM Low MM: 24 24905 97-43C 98074 314 14.3332 37 24966 97-56B 98078 16 14.3365 Operational MM = 14.342: Node = 16 4 24796 97-20E 98078 16 14.3420 6 24794 97-20C 98075 16 14.3421 7 24793 97-20B 98076 16 14.3421 8 24792 97-20A 98076 16 14.3421 19 24965 97-56A 98077 16 14.3422 34 24969 97-56E 98078 16 14.3421 35 24968 97-56D 98077 16 14.3421 36 24967 97-56C 98075 16 14.3421 Node = 48 9 24839 97-30D 98074 49 14.3421 10 24838 97-30C 98076 48 14.3421 12 24837 97-30B 98076 48 14.3421 13 24840 97-30E 98074 49 14.3421 14 24836 97-30A 98074 49 14.3421 16 24841 97-30F 98074 48 14.3421 Node = 80 15 24869 97-34A 98075 80 14.3421 17 24870 97-34B 98076 80 14.3421 20 24872 97-34D 98076 79 14.3421 39 25042 97-69D 98074 80 14.3421 40 25041 97-69C 98074 80 14.3421 41 25040 97-69B 98077 79 14.3421 43 25039 97-69A 98072 81 14.3421 44 25078 97-77B 98076 80 14.3421 Node = 314 22 24907 97-43E 98077 313 14.3421 23 24906 97-43D 98076 313 14.3421 25 24904 97-43B 98076 313 14.3421 26 24903 97-43A 98072 315 14.3421 45 25104 97-82A 98075 314 14.3421 46 25105 97-82B 98077 313 14.3421 47 25106 97-82C 98076 313 14.3421 49 25108 97-82E 98074 314 14.3421 Node = 346 28 24948 97-51E 98075 345 14.3421 29 24944 97-51A 98077 344 14.3421 30 24949 97-51F 98076 345 14.3421 31 24950 97-51G 98072 347 14.3421 32 24945 97-51B 98077 344 14.3421 33 24946 97-51C 98078 344 14.3421 High MM: Node = 48 (latest launch) 50 25169 98-10A 98078 47 14.3452 52 25171 98-10C 98078 47 14.6003 53 25172 98-10D 98076 48 14.3429 54 25173 98-10E 98075 48 14.3425 56 25170 98-10B 98078 47 14.3423 Various nodes (spares being maneuvered?): 5 24795 97-20D 98077 16 14.3696 18 24871 97-34C 98076 80 14.3704 38 25043 97-69E 98074 80 14.3728 42 25077 97-77A 98076 80 14.3758 48 25107 97-82D 98074 314 14.3718 "Anomalous" objects with very high MM; Iridiums 21 and 27 have failed: 11 24842 97-30G 98077 47 14.3907 21 24873 97-34E 98077 72 14.7805 27 24947 97-51D 98077 341 15.0401 From this, you can see how the 6 orbital planes are filling up. Five of the 6 planes now have between 6 and 8 satellites in operational orbits, and it looks like the Node = 58 plane is about to get filled as the five 98-10 objects move in. It's interesting that Iridiums 24 and 37 are in HIGHER parking orbits (lower MM), while the other "spares" are in lower orbits (with higher MM). Then there's the failed Iridiums 21 and 27, of which 27 is clearly out of control with a flash period of about 3 seconds. This object will be making evening passes in the northern hemisphere in April, and should be fun to watch for its flashes. Finally, Rob Matson notes in his Iridflar program that Iridium 11 doesn't produce "normal" flashes. Has anyone ever seen a flash from this object? I've looked several times, but have never seen any. Cheers, Rich Keen Coal Creek Canyon, Colorado, USA (39.877 N, 105.391 W, elevation 2728m)