SpaceX has another test planned that aims to reduce the amount of light pollution produced by its Starlink satellites, this one involving sunshades rather than an anti-reflective coating. Elon Musk first spilled the details on this plan in a tweet following the Starlink 6 satellite launch, revealing that there will be a few more launches before the sun visors are deployed.
Low-Earth orbit satellites like the ones launched by SpaceX are a particular problem when it comes to light pollution; long-exposure photography and space observations can be disrupted by these reflective satellites, which may appear like bright dots or long streaks in images. NASA is among the agencies that have raised concerns over the potential disruption caused by these satellites.
SpaceX has taken steps to address the concerns. In late 2019, for example, it launched a batch of Starlink satellites that included a single unit featuring an experimental anti-reflective coating. The company only included the coating on one satellite in order to see whether it worked and if it would have any sort of negative impact on the operation of the satellite.
Around the launch of the Starlink 6 batch of satellites last week, Elon Musk said in a tweet that the company was taking additional steps to reduce the brightness of these satellites:
Musk returned with additional details this week. SpaceNews reports that, according to Musk, SpaceX will test the use of an experimental ‘VisorSat’ sunshade, something described as more effective than the anti-reflective dark coating tested earlier this year. These shades are described as panels that will shield the satellites’ antennas from sunlight in a way similar to a patio umbrella.
At this point in time, SpaceX has a total of 420 Starlink satellites in orbit, which is just a sliver of the eventual 12,000 (or more) that it plans to launch. The sunshade concept obviously won’t address the brightness of the satellites that are already in orbit, but Musk pointed out that these satellites will likely only be orbit for a few years before deorbiting.