CEO Elon Musk has revealed more details about SpaceX’s plans to build and launch upgraded “VisorSat” Starlink satellites, part of the company’s work to ensure that the internet constellation can coexist with astronomy.
Back on April 22nd, Musk gave us the best glimpse yet of what he previously described as a sort of deployable sunshade for Starlink satellites. Designed to prevent orbital sunlight from reflecting off of each spacecraft’s shiny surfaces and disrupting ground-based astronomical observations, the SpaceX CEO said that the company’s very next Starlink launch – scheduled no earlier than “early May” – will carry one or several satellites with said sunshade installed, playfully nicknamed “VisorSat”.
Ultimately, Musk explained in significant detail the likely culprit of the spectacular visibility of Starlink satellites from the ground, discussed plans to reduce or wholly remove that flaring, and explicitly stated that SpaceX will do everything in its power to prevent its constellation from impacting science.
On April 22nd, Musk revealed that the sunshade he’d previously discussed would look “a lot like a car sun visor” and would be built out of dark, radio-transparent foam to avoid disrupting each satellite’s antennas while still preventing sunlight from reflecting off of their mirror-like surfaces.
Days later, he revealed a rough render of VisorSat’s design, showing an extremely simple pair of rotating foam ‘visors’ explicitly shaped to block sunlight from Starlink satellite antennas and not much else. Given the use of foam and a deployment mechanism no more complex than four actuating hinges, it’s entirely believable that this solution – if it works – could be cheap and light enough to be almost irrelevant for the overall spacecraft.
If it works, SpaceX’s ad hoc visor would effectively be the best possible solution for brightness, fully solving the issue while having a near-zero impact on the cost or functionality of each internet satellite. Of course, SpaceX will do what it’s known for and flight-test the new VisorSat design before getting ahead of itself, but if those tests are successful, it would be unsurprising if every future Starlink satellite features a visor.
However, in the process of explaining why Starlink satellites can appear so bright, Musk also hinted at one of the reasons that a visor alone cannot fully solve all of the sources of Starlink’s ground astronomy impact. After launch, Starlink satellites must raise and circularize their orbits to reach an operational altitude, a process that has typically taken 2-4 weeks. During that orbit-raising phase, Musk revealed that Starlink satellites must orient themselves in such a way that the entirety of their front and rear faces – including the solar array – is angled perfectly to reflect sunlight back to Earth.
To alleviate that issue, Musk has said that SpaceX will tweak the orientation and operation of satellites during the orbit raising period, but it’s difficult to see a way to consistently prevent bright reflections without big changes. If SpaceX can’t immediately find a way around that “Open Book” orientation, there will likely be anywhere from 60-180+ Starlink satellites raising their orbits on any given day if the company truly plans to operate a constellation of ~4400 satellites, let alone ~12,000 or ~40,000.
Once orbit-raising is complete, Musk believes that visors will effectively make Starlink satellites invisible to the naked eye, but more work will have to be done if SpaceX wants to fully mitigate Starlink’s astronomy impact.