correction to message

Thu, 6 Aug 1998 14:48:55 -0500

In my previous post, the Iridium satellites as suspected to have failed
contained an error: Instead of 11, 18, 21, 27, 22, 46 and 71; it should have
said 11, 18, 21, 27, 44, 46, 71.  The correct text is now listed below.

> Observers of Iridium satellites should be very careful to note that I and
> others have been confusing the common names of the satellites that we are
> observing. This confusion is derived from the OIG data that comes from
> USSpace Command. I reported yesterday that Iridium 46 was tumbling and in
> fact, it is really Iridium 24. This has been known for some time and is
> not a new failure. However, the reason for this is the coding that is
> produced when we get our element sets from OIG.  When I print out my
> predictioins, the common name that comes from OIG is printed out and I use
> it just as everyone else does. 
> Apparently, there are a total of 7 Iridium satellites that are not
> operating normally from what we have observed and from the technical
> information that has been provided to us on the net. There are two types
> of observations that tend to confirm that a satellite has possibly become
> unstable: a) slow tumbling, b) rapid tumbling.  Iridium satellites that we
> have identified as 11, 18, 21, 27, 44, 46, and 71 seem to be failed. These
> numbers are based on the Iridium numbers listed in the OIG data base. What
> OIG calls Iridium 20 is apparently the real Iridium 18 (as identified by
> Iridium LLC) and vice versa just as Iridium 46 is probably the real
> Iridium 24 and vice versa. There are possibly 6 other objects for which
> the names and identities are not correct. All this is caused by the
> movement of the satellites from engineering to operational orbits and the
> tracking problems by USSpace Command when two Iridium satellites in
> similar orbits pass close to each other in the sky.  
> We are hoping that Iridium will be able to post a comprehensive list that
> will let all space trackers know the correct identities in the very near
> future. It would hopefully tabulate the satellite number within the
> designated plane, the USSpaceCommand catalog number, the international
> designator and the common name (e.g. Iridium XX).
> The observations that I and others make are strictly our own observations
> and opinions based upon the information that we use from OIG (or other
> sources). We attempt to be as accurate as we can; however, under the
> conditions that exist with satellite maneuvers and with two satellites
> passing close to one another on various occasions, it should be expected
> that this confusion will continue.  Anyone who may choose to act on any
> information posted on this net would be well advised to check and double
> check the facts with the posters before jumping to any conclusions.  
> Paul D. Maley
> tel. 281-244-0208; fax: 281-244-1140
> email:
> latitude 29.6049 north, longitude 95.1086 west, elev 6m