** Updated August 6, 2008**
For a summary of the Iridium launch sequence, see my Iridium Launch Chronology. There is now also a summary of Iridium Failures.
Latest changes (see below for earlier changes):
** In late July 2008, Iridium 95 (27375, 2002-005D), up till then a spare satellite in orbital plane 3, entered the operational constellation, evidently to replace Iridium 28 (24948, 1997-051E). Initially, Iridium 28 remained close to its nominal position in the constellation, so had presumably failed on station.
Orbital <-------- Operational satellites --------> Spares (in current sequence) Plane Plane 1: 21 72 75 70 62 63 64 65 66 67 68 14; 74 (partial failure?) Plane 2: 22 23 76 25 45 46 47 20 49 26 3 11 Plane 3: 55 95 29 31 30 32 33 57 58 59 60 91 94 96; Plane 4: 19 34 35 97 5@ 6 7 8 4 37 61 51 (partial failure?)@; Plane 5: 50 56 52 53 84 10 54 12 13 83 86 90 (launched to plane 3, but has been migrated to plane 5) Plane 6: 18 42 40 39 80 77 15 81 82 41 43 98 (launched to plane 4, but has been migrated to plane 6)
Original <----- Failed -----> <- Failed -> Note that some of the failed Orbital (but still in orbit) (decayed) satellites have drifted from Plane the original orbital planes Plane 1: 73t Plane 2: 69t 24t 71t 48d Plane 3: 28 27d Plane 4: 36t Plane 5: 2t 914t 911t 16t 85d 9d Iridium 2 has drifted far from Plane 6: 920t 921t 44t 38t 17 79d its original launch plane
t indicates satellites that have been reported as tumbling out of control.
Notes:
This is Rod Sladen's personal opinion of the status of the Iridium constellation, and the information herein has not been confirmed by the new owners, Iridium Satellite LLC, nor by Boeing who are maintaining the system for them.
Iridium 11 (until recently referred to by OIG as Iridium 20), Iridium 14, Iridium 20 (until recently referred to by OIG as Iridium 11) and Iridium 21 are the second (i.e. replacement) satellites known by those names. They were previously known as Iridium 20a, Iridium 14a, Iridium 11a and Iridium 21a respectively.
Iridium 911, Iridium 914, Iridium 920, Iridium 921 are the (failed) satellites originally known as Iridium 11, Iridium 14, Iridium 20 and Iridium 21 respectively.
d indicates satellites that have already decayed:
Iridium 79 (25470, 1998-051D) decayed on 29 November 2000
(see http://www.satobs.org/seesat/Nov-2000/0256.html),
Iridium 85 (25529, 1998-066C) decayed on 30 December 2000
(see http://www.satobs.org/seesat/Dec-2000/0409.html),
Iridium 48 (25107, 1997-082D) decayed on 5 May 2001
(see http://www.satobs.org/seesat/May-2001/0028.html),
and
Iridium 27 (24947, 1997-051D) decayed on 1 February 2002
(see http://www.satobs.org/seesat/Feb-2002/0002.html)
Iridium 9 (24838, 1997-030C) decayed on 11 March 2003
(see http://www.satobs.org/seesat/Mar-2003/0116.html)
@ Iridium 51 *may* have replaced Iridium 5 in the operational constellation on 11 August 2001.
Note that the identities of various members of the Iridium
constellation have been confused at various times in the past.
Some interchanges of identities seems to have become permanent:
Iridium 24 is tumbling, and correctly labelled by Spacecom as
Iridium 24, and correctly tracked, but under 25105 (1997-082B)
which are the catalog number and launch identifier which
originally belonged to Iridium 46.
Iridium 46 is operational, and correctly labelled by Spacecom as
Iridium 46, and correctly tracked, but under 24905 (1997-043C)
which are the catalog number and launch identifier which
originally belonged to Iridium 24.
Iridium 11 is spare, and is now correctly labelled by Spacecom as
Iridium 11, and correctly tracked, but under 25578 (1998-074B)
which are the catalog number and launch identifier which
originally belonged to (the second) Iridium 20.
Iridium 20 is operational, and is now correctly labelled by
Spacecom as Iridium 20, and correctly tracked, but under 25577
(1998-074A) which are the catalog number and launch identifier
which originally belonged to (the second) Iridium 11.
In late July 2008, Iridium 95 (27375, 2002-005D), up till then a spare satellite in orbital plane 3, entered the operational constellation, evidently to replace Iridium 28 (24948, 1997-051E). Initially, Iridium 28 remained close to its nominal position in the constellation, so had presumably failed on station.
(January 2008) Iridium 90 [previously labelled as Iridium 91] which had been manouvering since mid October2005 has now arrived in orbital plane 5
(May 2007) Iridium 98, which had been manouvering since late June 2005, has now arrived in orbital plane 6
In early January 2007, Iridium 97 (27450,2002-031A), a spare satellite in orbital plane 4, entered the operational constellation, evidently to replace Iridium 36 (24967, 1997-056C). Iridium 36 remained close to its nominal position in the constellation - it had evidently failed on station.
On or about January 10, 2006, Iridium 21 (25778, 199-032B), one of two spare satellites in orbital plane 1, was raised to operational altitude, presumably to replace Iridium 74 (25345, 1998-032B),. which was lowered to the engineering orbit. It is as yet unclear whether Iridium 74 has failed completely
On January 1, 2006, the Spacecom labelling of Iridium 90 and Iridium 91 was interchanged. There was no change to the operational constellation.
In August 2005, Iridium 17 evidently failed, and Iridium 77 took its place in the operational constellation. This left orbital plane 6 without a spare satellite.
In April 2005, Iridium 16 was removed from the operational constellation, and subsequently Iridium 86 took its place in the operational constellation. This left orbital plane 5 without a spare satellite.
On January 29, 2004, the OIG/Spacecom labelling of Iridium 11 and Iridium 20 was
interchanged.
There was no change to the operational constellation.
Iridium 82 replaced Iridium 38 in orbital plane 6 on or about September 17, 2003.
Iridium 30 and 31 exchanged places in the constellation on September 19-22, 2002.
2 further spares (Iridium 97 and 98) were launched at 0933 UT on 20 June 2002 from Plesetsk Cosmodrome by Eurockot.. This launch was directed at orbital plane 4. Iridium 98 was subesquently moved to orbital plane 6.
5 additional spare Iridium satellites (Iridium 90, 91, 94, 95 and 96) were launched from Vandenberg AFB aboard a Delta II rocket on 11 February 2002 at 17:43:44 UT. The originally intended launch on 8 February 2002 at 18:00:30 UT was scrubbed at the last moment, while the launch opportunities on 9 February 2002 at 17:54:55 UT and 10 February 2002 at 17:49:19 UT also had to be scrubbed. See http://www.boeing.com/news/releases/2002/q1/nr_020211s.html and http://spaceflightnow.com/delta/d290/status.html for more details on the launch. This launch was directed at orbital plane 3, which previously had no spares. Perhaps surprisingly, there is so far no indication that it is intended to drift some of the spares to other orbital planes. Iridium 90 (initially labelled as Iridium 91) was subesquently moved to orbital plane 5.
@ Iridium 51 *may* have replaced Iridium 5 in the operational constellation on 11 August 2001.
The previous change to the operational constellation was the replacement of Iridium 9 by Iridium 84.
Additional Notes:
Iridium 2 has drifted far from its original orbital plane (as have several of the tumbling satellites). At one time, it was deliberately allowed to drift to become the spare in another plane (plane 4?), but it evidently failed on arrival in the new plane, and continues to drift out of control.
At the Iridium Satellite LLC press conference call on 12
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 would include
Iridium 82, 84 and 86 which have since become operational.
Also at the Iridium Satellite LLC press conference call on 12
December 2000
(see http://www.ee.surrey.ac.uk/Personal/L.Wood/constellations/iridium/conference-call-Dec-2000.html),
plans were announced to launch further spare satellites for the
constellation:
"We'll be launching seven more in the next year or so.
We have the first launch scheduled for next June, June of 2001.
That will be a Delta 2 launch; we'll be putting five spare
satellites into orbit. The following spring, roughly March of
2002, we'll be launching two more and in that case we'll be using
the Russian rocket. So we will inject seven more spares into the
system, so we'll have more than two spares in each orbit, and
that will give us the life that we believe is there"
These launches were in fact delayed until 2002.