SpaceX: Starlink DarkSat shows 'a notable reduction' in brightness

Featured Image Source: SpaceX Starlink

SpaceX initiated the Starlink project to fund its ambitious space program. Starlink consists of building a mega-constellation of internet-beaming satellites in low Earth orbit. In total, the company has placed 360 Starlink satellites into orbit out of the 12,000 slated to deploy. Astronomers have been vocal about Starlink satellites appearing too bright in the night sky. Many worried that the constellation could interfere with their astronomical observations. Starlink is launched in clusters of 60 satellites per mission, they are especially bright soon after launch, visible in train-like formations when flying at lower altitudes before reaching a higher, operational orbit (pictured below). SpaceX officials said the satellites' reflectivity was a surprise and that engineers are actively working on a solution to decrease Starlink satellites' brightness. "We certainly knew this was a novel spacecraft design in a novel architecture, but the level of brightness and visibility was a surprise to us," said Patricia Cooper, Vice President of satellite government affairs at SpaceX, who represented the company at the a American Astronomical Society meeting this year.

Image Source: Supplied

SpaceX assures it will find solutions to reduce the impact of Starlink satellite's on astronomy. Currently, SpaceX is testing an experimental satellite, referred to as "DarkSat," that was deployed in January 6. DarkSat features an anti-reflecting coating at the bottom to reduce its reflectivity, which reduces brightness in the night sky. Engineers must see if the coating's anti-reflective properties affect the satellite's performance due to possible thermal changes. During a broadcast of the previous Starlink mission, a SpaceX commentator Jessica Anderson said that DarkSat has demonstrated a "notable reduction" in its brightness:

"Preliminary results show a notable reduction."

The founder of SpaceX Elon Musk, shared that engineers are in the process of developing a "sunshade." The satellite "sunshade" would deploy like an umbrella to cover the satellite in order to reduce its visibility from Earth. Anderson shared that the experimental Starlink satellite with the "sunshade" will be tested on a future mission.

At the Satellite 2020 conference, Musk stated he does not believe Starlink would have a negative effect on astronomy. "I am confident that we not cause any impact whatsoever in astronomical discoveries," he said. "Zero. That’s my prediction. We will take corrective action if it’s above zero." Though, he did assure that SpaceX is cooperating with astronomers to ensure less visibility. He stated:

"We are working with senior members of the science community and senior astronomers to minimize the potential for reflection from the satellites. We’re running a bunch of experiments. [...] To minimize the potential for any impact."

Starlink satellites are expected to reduce visibility once they reach an operational orbit of approximately 550 kilometers above Earth. Each satellite is equipped with an ion thruster propulsion system powered by Krypton to move along orbital lanes. It will take several weeks until they all move into a higher orbit, where their visibility should decrease significantly in the coming months. 

Musk explained Starlink will offer "a pretty good experience" to areas with dense populations, "It will be a pretty good experience because it'll be very low latency. We're targeting latency below 20 milliseconds, so somebody could play a fast-response video game at a competitive level, like that's the threshold for the latency." Every cluster of 60 satellites could deliver 1 terabit of bandwidth that could potentially support 40,000 users streaming ultra-high-definition content at the same time. He also stated, the Starlink network will serve the "3 or 4 percent hardest to reach customers for telcos" (telecommunications) and rural areas where internet connectivity is unreliable or non-existent. The company aims to initiate offering services in parts of Northern United States and Canada by the end of this year.