Summary of Iridium constellation status, 06 January 2001 Orbital <-------- Operational satellites --------> Spares Failed Plane Plane 1: 74 72 75 70 62 63 64 65 66 67 68 14 21 73? Plane 2: 22 23 76 25 45 46 47 11 49 26 03 20 69? 24t 48t 71t Plane 3: 55 28 29 30 31 32 33 57 58 59 60 27t Plane 4: 19 34 35 36 05 06 07 08 04 37 61 51? Plane 5: 50 56 52 53 # 10 54 12 13 83 16 84# 86 02? 914t 09t 911t 85d Plane 6: 18 42 40 39 80 17 15 81 38 41 43 77 82 920t 921t 44t 79d Notes: # Iridium 09 was removed from its position in plane 5 during September 2000. As of 06 January 2001, Iridium 84 appears to be in process of being raised to fill the gap. 11, 14, 20 and 21 are the second (replacement) satellites known by those names They were previously known as 11a, 14a, 20a and 21a respectively. 911, 914, 920, 921 are the (failed) satellites originally known as 11, 14, 20 and 21 respectively. ? indicates satellites whose status is unclear, but which are almost certainly incapable of being controlled. But one of these (probably iridium 51) is evidently still regarded as usable (see below). t indicates satellites that have been reported as tumbling out of control. d indicates satellites that have already decayed: Iridium 79 decayed on 29 November 2000 (see http://www2.satellite.eu.org/seesat/Nov-2000/0256.html), and Iridium 85 decayed on 30 December 2000 (see http://www2.satellite.eu.org/seesat/Dec-2000/0409.html). Of the spare satellites, Iridiums 77, 82 and (in recent months) 14 (ex 14a), 20 (ex 20a) and 21 (ex 21a) have all had their orbits regularly maintained. Until the manouver of 05 January 2001, Iridium 84 appears to have had its orbit adjusted only once in recent months - back in September 2000 when its orbit was raised. (See http://www2.satellite.eu.org/seesat/Sep-2000/0303.html) At the Iridium Satellite LLC press conference In December 2000 (see http://www.ee.surrey.ac.uk/Personal/L.Wood/constellations/iridium/conference-call-Dec-2000.html), a figure of 8 operational spares was quoted. This suggests that one of the satellites (probably Iridium 51) flagged above as "?" (status unknown) is still regarded as functional. Recent observations of flares (or of lack of flares, or of flashes indicating tumbling) from the relevant satellites (Iridiums 02, 51, 69, 73) would help to clarify the situation, as would any elset showing any of these satellites being manouvered, though all recent elsets that I have checked show no such adjustments. Iridium 2 has drifted far from its original orbital plane (as have several of the tumbling satellites). At one time, it was suggested that it was deliberately being allowed to drift to become the spare in another plane (plane 3?), but it has passed that plane over a year ago, and continues to drift, so it is probably out of control. I myself have never seen a flare from Iridium 2, and suspect that it may be tumbling. ----------------------------------------------------------------- Unsubscribe from SeeSat-L by sending a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org http://www2.satellite.eu.org/seesat/seesatindex.html
This archive was generated by hypermail 2b29 : Sat Jan 06 2001 - 07:19:07 PST