SpaceX deployed experimental Starlink 'DarkSat' to test an anti-reflective coating that aims to make the satellite less bright

SpaceX deployed experimental Starlink 'DarkSat' to test an anti-reflective coating that aims to make the satellite less bright

Source: Starlink

SpaceX aims to fund their space program by offering internet services. The company has been deploying small desk-sized Starlink satellites into low Earth orbit. Starlink will be a constellation consisting of 12,000 satellites that will beam high-speed broadband internet across the globe. SpaceX officials previously stated that Starlink broadband internet will be affordable enough that areas where internet is non-existent, or unreliable will benefit from their service. Currently there are a total of 230 satellites in low Earth orbit, out of the 12,000 they aim to deploy. Scientists voiced their concerns about Starlink satellites appearing too bright in the night sky and how a constellation could interfere with their astronomical observations. Starlink is launched in batches of 60 satellites per mission, and are especially bright soon after launch, visible in trainlike formations when flying at lower altitudes, before reaching their final -higher- orbit, where they should become less visible from the ground to the naked eye (video below).

SpaceX President and Chief Operating Officer, Gwynne Shotwell, said the satellites' reflectivity was a surprise, "There are lots of people that have looked at Starlink and looked at the satellites, lots of people knew what we were doing, and no one thought of this. We didn’t think of it. The astronomy community didn’t think of it. It happened … Let’s go figure that out.” And added that the company wants to do the “the right thing” in finding a solution to ensure the night sky remains clear for astronomers and inspiration. “Astronomy is one of a few things that gets little kids excited about space. There are a lot of adults that get excited, too, who either depend on it for their living or for entertainment. But we want to make sure we do the right thing, to make sure little kids can look through their telescopes. It’d be cool for them to see a Starlink. I think that’s cool. But they should be looking at Saturn and the moon," she said.


This month (January 6), they deployed one satellite with an experimental anti-reflectivity coating on the bottom, called DarkSat. “This next batch has one satellite that we’ve put a coating on the bottom. This is going to be an experiment … We’re going to do trial and error to figure out what’s the best way to get this done. But we are going to get it done,” Shotwell assured. First, engineers plan to test DarkSat's coating to see if its anti-reflectivity properties could cause thermal changes that could affect the satellites internet signal performance. It will take a few more weeks until the DarkSat raises into its final orbit where engineers could test it. "It takes a few weeks for those satellites to reach their final orbit destination, so we don’t have the results of that DarkSat experiment just yet, but we’ll be sure to share what we’ve learned as the data becomes available," a SpaceX Engineer, Lauren Lyons said. The Starlink constellation will be deployed into three orbital shells with operational altitudes of 340 kilometers (210 miles), 550 kilometers (340 miles) and 1,150 kilometers (710 miles). DarkSat's orbit is still low, at about 366 - 368 kilometers. DarkSat is expected to reach operational altitude by the end of February 2020. Once reaching the final orbit, engineers will test the satellite's performance, then determine if they will use the anti-reflective coating on all their satellites or test another method to reduce brightness. 



SpaceX plans as many as 24 Starlink's dedicated rocket launches with 60 satellites each this year. They target to offer Starlink's service in some parts of the Northern United States and Canada soon, and aim to roll-out global coverage by 2021.


About the Author

Evelyn Arevalo

Evelyn Arevalo

Evelyn J. Arevalo joined Tesmanian in 2019 to cover news as a Space Journalist and SpaceX Starbase Texas Correspondent. Evelyn is specialized in rocketry and space exploration. The main topics she covers are SpaceX and NASA.

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