Iridium Block 1 Constellation Status

Click here for the Block 1 Status Sheet

Here you find the current status of the Iridium Block 1 satellites according to my best knowledge as an Iridium Flare lover. It is not official information and not affiliated with Iridium Communications. Recent deorbit and re-entry events are based on current TLEs from and Twitter updates from @IridiumBoss, predicted reentry dates are estimates by SatFlare and

As de-orbits are proceeding rapidly, I check on the satellites daily and update the sheet whenever there is a change. The time stamp of the update is shown on the sheet.

ATTENTION: Updates to the status sheet can only be accessed through this page. Every time I upload an update, the URL to the sheet changes. A bit annoying, but it’s the settings of the website that I cannot change. So in case you want to bookmark, choose THIS page.

Note on the Status Sheet: 

  • The blue block “Still flaring” shows the satellites that are still in a stable orbit and can flare reliably.
  • The gray block “Tumbling” includes the deorbiting satellites that have already been passivated. They are out of control but on a predictable trajectory, so you might see them tumble. This can produce brief flashes or even tiny flares somewhere along the trajectory.
  • The date format is European: DD.MM.YYYY, time reference is UTC.

Click here for the Block 1 Status Sheet

Last update: 9 November 2019

NEW: Note on update frequency

  • After the recent reentries on 11 May 2019, I will still check on the satellites regularly, but there aren’t any major changes to be expected before around November 2019 when SVs 61 and 97 will be deorbited.
  • Occasional updates would reflect changes in the estimated reentry date of SV 96.
  • So if you see an old date for the last update, the list is still alive and maintained! 

Some hints for late-stage flare-watching:

Many flare apps do not show you all the flares for the following reasons:

  • Most of them do not show spare, unstable or out-of-service satellites. All of the remaining Block 1 satellites loosely fit into this category, none of them is in service any more.
  • Most apps filter flares according to their magnitude, i.e. perceived brightness. Only a few apps allow for manual adjustment, the others might not show you e.g. a flare with an above-zero magnitude (or whatever criteria they might use).
  • The flare apps are of course not updated by their coders any longer, so some have become unreliable or incompatible or show bugs.

The best and most reliable app for iOS is GoSatWatch. It is quite pricey however and you might not want to invest at this stage. There is a free trial though.
A good source for desktop is CalSky. Its default setting is on “hobby astronomer”. Select “astronomer” in order to get all results and decide yourself which ones are feasible for you.