The "Old and Busted" Iridium satellites flared like crazy because they had big flat metal surfaces for their phased array antennas (that were certainly so shiny completely by accident and never intended to call attention to themselves). the "New Hotness" Iridium satellite antennas are very different and don't have this gimmick characteristic.

The visible Starlink train saga is represented in several questions here and in Astronomy SE so won't cover it here. Did nobody in the Astronomy community think 12,000 new satellites in LEO might be a problem?

Starlink satellites are giant flat, square metal pancakes with tall, flat-segmented solar panels, and they now have one preferred attitude during their rise from deployment altitude (low, so easy to quickly deorbit the duds) to operational altitude and phasing within a given inclination ring, and a second preferred attitude once operational.

Question: Are Starlink satellites flaring? In the same way that the occasional geometry occurred when a near specular reflection of the Sun on to Earth's surface occurs for other satellites, does this happen for Starlinks? Or do the now fairly well established preferred attitudes discussed above pretty much preclude any flaring?

From this answer to Why no Iridium-level flares from other satellites?

Iridium flare GIF GIF Source

Old and Busted (original Iridium)

below "View of one of the Main Mission Antenna. The hinged base is on the right side." Cropped. From satobs.org/iridsat.html.

old Iridium antenna panel click for larger

New Hotness (Iridium Next)

Iridium Next click for larger

above: Conceptual drawing of Iridium-NEXT from harris.com/solution/hosted-payload-solutions.


Yes it appears that Starlinks are/can flare. Here are two videos showing Starlink flares after launch (while still in the train formation):

These videos are both two and one years old, respectively. The second video begins with a (shaky) zoomed in view that shows (I believe, based on pictures in below linked blog post of the satellites) the antennas causing the flare.

SpaceX's Starlink update blog post ASTRONOMY DISCUSSION WITH NATIONAL ACADEMY OF SCIENCES (posted over a year ago) has a very nice write-up on Starlink brightness:

When sunlight hits a specular surface of the spacecraft and reflects, the vast majority of light reflects in the specular (mirror reflection) direction, which is generally out toward space (not toward Earth). Occasionally when it does, the glint only lasts for a second or less. In fact, specular surfaces tend to be the dimmest part of the satellite unless you are at just the right geometry. [emphasis mine]

The blog makes no mention of this phenomenon being exclusive to the post-launch/phasing time periods. I could not find any pictures/video of a Starlink flare occurring while in the operational orbit.

  • $\begingroup$ Yep, the newer ones are fainter than the first batches, magnitudes shifted by ~2 I read, but still visible. Also, 3% are unresponsive in orbit (according to a business insider item) $\endgroup$ – user40414 May 14 at 14:26
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    $\begingroup$ Perfect Stack Exchange answer! A block quote from an authoritative source that specifically addresses the question, a boolean-like answer (yes) and a couple of supporting videos. Thanks! $\endgroup$ – uhoh May 14 at 15:17
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    $\begingroup$ Starlink satellite flares can be seen for instance on astronomy.com/news/2020/03/…. Smartphones capture them well. A highly efficient CCD on a telescope even more so. The flares are much brighter than nebulous filaments. $\endgroup$ – user40414 May 14 at 16:18

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