That brightness worries many astronomers, who say that the huge Starlink constellation could seriously disrupt a variety of scientific observations. And Starlink will indeed be huge, if all goes according to SpaceX's plan: The company has approval to launch 12,000 craft to low Earth orbit (LEO) and has applied for permission to loft 30,000 more. (For perspective, humanity has launched just 9,400 objects to orbit since the dawn of the space age in 1957).
SpaceX founder and CEO Elon Musk has said that the company will find a way to make Starlink craft fade from scientists' sight, predicting that the constellation will end up having no impact whatsoever on astronomical discoveries. SpaceX has been working with the astronomical community to help make this happen, researchers say, and the company has already tried out some mitigation measures.
For example, one of the 60 Starlink satellites that launched atop a Falcon 9 rocket this past January sported an experimental coating to make it less reflective. Observations show that this "DarkSat" is considerably dimmer than its brighter Starlink cohorts, but probably not dim enough to quell most astronomers' concerns about the megaconstellation.
But SpaceX is taking additional measures as well, which brings us to the new accessory. Musk tweeted the following on Wednesday (April 22), in response to a Twitter follower who wished SpaceX luck on a 60-satellite Starlink launch that day: "Thanks! We are taking some key steps to reduce satellite brightness btw. Should be much less noticeable during orbit raise by changing solar panel angle & all sats get sunshades starting with launch 9."
He gave some details about the sunshades, which will presumably reduce solar reflection off the satellites' bodies, in a subsequent tweet that day: "It’s made of a special dark foam that’s extremely radio transparent, so as not to affect the phased array antennas. Looks a lot like a car sun visor."
Thanks! We are taking some key steps to reduce satellite brightness btw. Should be much less noticeable during orbit raise by changing solar panel angle & all sats get sunshades starting with launch 9.April 22, 2020
The sunshade-equipped satellites will begin flying soon, because Starlink Launch 9 should be just around the corner. Wednesday's liftoff was Launch 7, and Launch 8 is targeted for May.
Each Starlink mission lofts 60 spacecraft. To date, SpaceX has launched 422 of the satellites to LEO, counting two prototypes that went up in February 2018. Musk has said that Starlink can provide "minor" internet coverage with at least 400 satellites and "moderate" service with about 800, so the constellation will likely be operational relatively soon.
The sunshades' effectiveness should also be apparent in short order. Astronomers will doubtless be tracking the modified satellites, hoping they don't stand out too much against the dark sky.
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Mike Wall is the author of "Out There" (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook.