Solar array flare predictions with IRIDFLAR

From: Matson, Robert (ROBERT.D.MATSON@saic.com)
Date: Tue Jun 18 2002 - 14:04:14 EDT


Hi Willie and List,

> Thanks Bjorn, Rob and others for the nice explanation for what we saw.
> I must admit, I am one of the lazy ones relying on heavens-above for
> Iridium flare predictions, particularly when dealing with the public
> since I know that the non-performer-Iridiums are filtered out
> beforehand for me.

For the general public, I agree that Heavens-Above is the best
choice.  It's easy to use and does not require the user to download
software or orbital elements.

> I thus have not really used IRIDFLARE for predictions, only for
> some after-the-event analysis.  From my recent experience, I'm
> surely going to change my plan of attack now.  Going after solar
> array flares are well worth the effort from what I saw.

I'll warn you that solar array predictions are not as reliable
as those for the MMAs since solar array pointing is not nearly
as critical to spacecraft operations.  So you'll see a larger
range of visual magnitude error in those predictions -- some
brighter, some dimmer.

> Does IRIDFLAR give an indication of the "certainty" of a particular
> prediction or do one need to remember which are the non-performer
> Iridiums?

If you download your Iridium TLEs from Mike McCants' website, the
name line for each Iridium contains a status flag.  Tumbling sats
are tagged with "t", and spares (at lower altitude than the
operational constellation) are tagged with "?".  IRIDFLAR will
do predictions for the ? sats, which generally do flare as
predicted.  It skips predictions for the (many) tumbling sats.
The one-character status flag does appear in IRIDFLAR's output,
so you'll know which ones are questionable.

Best,
Rob

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