Hello everybody: There have been a number of messages about Iridiums recently. Let me see if I can provide an even more current update. The four failed IR's are still: 11,20,21,27. However, if a satellite (other than the 4 above) does not flare or flare at the correct magnitude (and is not observed to be tumbling), it more than likely is still a working spacecraft, regardless of the orbit it is currently in. Once an IR is observed to be flashing, it is likely that the thruster control has failed, and the satellite is likely to cease functionality. At certain times, a satellite will either go into or be intentionally placed in 'thruster control mode'. As of today, IR 5 and IR 48 are in this mode. It is not always possible to tell by looking at the elements that this has occurred, even though changes in the drag term may be a good signal. When an IR goes into the thruster control mode, the deadbands increase to 3.5 to 4.0 degrees which will cause the mirror/flare angles to be way off target. The deadbands will need to be tightend up in order to have a fully functional satellite system made up of spacecraft with similar deadbands. Reports of a satellite going 'off line' that appear on SEESAT should be factored into those programs such as GSOC where there is a lot of public access. However, confirmation (as has already occurred with IR 5) is important before deleting a satellite. The satellite should be deleted until the signal is given that it is back in working order (if that occurs). Two months ago I sent emails to several observers at high latitudes to report observed vs predicted flare magnitudes so that I can keep track of these variations. From the variety of reports received on the net, it is probably useful to ask that any observer who is capable of making ACCURATE observed maximum flare magnitudes to report them as convenient. You can do so directly by using my email address below. In order for the observations to have maximum impact, the elsets used should not be more than a few days old. Requested info includes: 1.Date 2.Time (UT) 3.IR number/USSPacecom or Int'l ID 4.predicted maximum magnitude (compared to star/planet whose brightness is known) 5.observed maximum magnitude ( " ) 6.age of element set used (if known), or epoch For ease of reporting, this can be done in a summary after a few weeks time rather than reports on individual events. Because there are so few bright calibration sources in the sky, I have recommended looking at flares that are -1 or fainter. This opens up the possibility of observing more flares, though they are not spectacular. I would also appreciate reports of double flaring which I and others have seen from some Iridiums. The double flaring should be very specific regarding the moment of the first flare and the number of seconds between the max of that flare and the max of the second. In some cases the first flare occurs on the predicted position and the second one thereafter. The process has also been observed to occur in reverse order. In summary, the Iridium constellation offers an opportunity for SEESAT observers to provide interesting information on the status of its individual satellites. Paul Paul D. Maley United Space Alliance DO5/Cargo Operations NASA Johnson Space Center Houston TX 77058 USA tel. 281-244-0208 email: paul.d.maley1@jsc.nasa.gov latitude 29.6049 north, longitude 95.1086 west