For modern astronomers, satellites are just a part of life. There are more than 2,000 active people currently orbiting the Earth, and the smartest senses in space photography have managed to come up with smart ways to remove single fly from their space images.
But then there is Starlink. The first stages of SpaceX's plan to launch up to 42,000 satellites to give Earth complete internet coverage have clocked in 122 objects so far; after the first major launch in May, astronomers were worried.
Now a second launch has occurred, and their concerns have really begun to work.
Wow !! I'm in shock !! The huge amount of Starlink satellites crossed our sky tonight at @cerrotololo. Our DECam exposure was greatly affected by 19 of them! The Starlink satellite train lasted for over 5 minutes !! Pretty depressing … This is not cool! pic.twitter.com/gK0ekbpLJe
– Clarae Martínez-Vázquez (@ 89Marvaz) November 18, 2019
During the early morning hours of November 18 at the Cerro Tololo Inter-American Observatory (CTIO) in northern Chile, the trail of recently launched Starlink satellites flew overhead and absolutely fills a picture taken by Dark Energy Camera (DECam).
Each of the dashed line tracks in the image below is a Starlink satellite.
While taking about 40 exposures of small and large magellanic clouds, SpaceX's Starlink satellite train entered the camera's vision about 90 minutes before sunrise, shining brightly in the sunlight early in the morning and taking a full five minutes to pass from the telescope's view.
"Wow !! I'm in shock," wrote CTIO astronomer Clara Martinez-Vazquez on Twitter. She noted that there were 19 satellite tracks, which is far more than a regular satellite past.
Although the satellites are usually dark in the night sky (which still causes some problems), shortly after the sun goes down, or early in the morning when the sky is still black, sunlight can still hit the satellites, making them visible both with good looking astronomical telescopes and just plain old binoculars.
"These things are big enough that when they are sunlit, they are bright enough to pick up everything from binoculars and larger ones," said Cees Bassa of the Netherlands Institute of Radio Astronomy Forbes.
And astronomers are not impressed. As we have previously reported, they have raised some major problems with Starlink. First, many of these orbits will be in orbit, which can dramatically affect how astronomers can see and listen to the sky.
"A complete constellation of Starlink satellites is likely to mean the end of terrestrial microwave radio telescopes that can scan the sky for weak radio objects," Swinburne University astronomer Alan Duffy told ScienceAlert in May after the first launch of Starlink satellites.
The second round of 60 Starlink satellites was launched just over a week ago on November 11, so that they have not yet reached their final operational altitude – but that altitude is expected to be lower than for the first round.
Sky watchers also find that Starlink is more reflective than other satellites. If thousands of extra satellites were not already a problem on their own, the fact that they are extra shiny is just another thing that astronomers are pulling their hair out about.
Agreed, sent a note to the Starlink team last week specifically about albedo reduction. We get a better sense of this when satellites have lifted orbits and matrices are tracking the sun.
– Elon Musk (@elonmusk) May 27, 2019
Astronomers can remove the traces from their images when Starlink swans in sight, but much of the information scientists use is in the raw images, not the beautiful images we see. In addition, it is one thing to remove a single satellite track from an image, and another to delete 19.
So far, some people manage by playing fun at SpaceX's Elon Musk on social media.
– 💫 Astro Noel 💫 (@astro_noel) November 18, 2019
How astronomers and SpaceX will solve these conflicting needs is still unknown, but with two more launches planned this year, there is a chance that this will not be the last we hear of this problem.