How SpaceX plans to make its Starlink satellites astronomer-friendly

SpaceX has detailed how it intends to minimize disruption to astronomical research caused by the launches of its Starlink satellites.

The Starlink project aims to bring global broadband internet to all via a network of satellites, which have been launching since 2018 and are now up to 420 operational satellites in total. There are plans to begin a private beta of the service as soon as this summer.

However, astronomers have expressed reservations about the project, including concerns raised by the International Astronomical Union that the launches will interfere will scientific work. They are concerned about the Starlink satellites more than other satellites both because they are constellation satellites, meaning that they are launched in large batches which are more disruptive than single launches, and because they are in low-Earth orbit, meaning they are closer to the planet than most satellites.

Representatives from SpaceX, including CEO Elon Musk, detailed how they planned to reduce the impact of their satellite launches at the Astro2020 meeting last week, as reported by phys.org.

The satellites cause problems for astronomers because they are highly reflective, so they reflect light from the sun and disrupt telescope observations. This problem is particularly pronounced during the launch and during the phase in which they raise their altitudes into the correct orbit.

“The Starlink satellite design was driven by the fact that they fly at a very low altitude compared to other communications satellites,” SpaceX explained in a press release. “We do this to prioritize space traffic safety and to minimize the latency of the signal between the satellite and the users who are getting internet service from it. Because of the low altitude, drag is a major factor in the design.”

The company is considering two changes to the satellite design to mitigate the reflection issue. Firstly, it is experimenting with different materials to create a satellite which is less reflective, called a “DarkSat.” Secondly, it is trying out a “sun visor solution” to deflect sun away from the satellites. This should help reduce infrared radiation which is caused when the satellites’ black paint absorbs heat from the sun.

The company reports that the first sun visor-type satellite will be launched this month, and that from June onward all newly launched satellites will be fitted with a sun visor.

In addition, SpaceX will change the way that the satellites move and are inserted into orbit. The new maneuver would involve the satellites facing the sun “edge-on,” so less surface area is exposed to direct sunlight which should further reduce reflections.

SpaceX has worked with astronomy researchers including those at the Vera C. Rubin Observatory to come up with these measures to minimize disruption.

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