NEWS ITEM
Dark-Coated Starlink Satellites are Better but not Perfect, Say Astronomers
A
n anti-reflective coating applied to some newer satellites in SpaceX’s Starlink constellation reduces their overall reflectivity by half but is less effective at certain wavelengths – meaning that ground-based astronomical observations are still being impaired by satellites passing through the telescope’s field of view. That is the finding of Takashi Horiuchi and colleagues at the National Astronomical Observatory of Japan, who used the 1.05 m Murikabushi Telescope at the Ishigakijima Astronomical Observatory (IAO) to determine the brightness of the so-called “DarkSat” model at different wavelengths.
as streaks in astronomical images taken from Earth-based telescopes, and astronomers’ concerns were heightened when the new satellites proved to be brighter than 99% of the approximately 200 artificial objects that were previously visible with the naked eye.
STARLINK STREAKS
“Significant physics and engineering effort is still necessary before the Rydberg analyzer can integrate into a field-testable device,” Cox said. “One of the first steps will be understanding how to retain and improve the device’s performance as the sensor size is decreased. The Army has emerged as a leading developer of Rydberg sensors, and we expect more cutting-edge research to result as this futuristic technology concept quickly becomes a reality.”
SpaceX launched the first 60 small satellites in its planned 12,000-satellite Starlink constellation on 24 May 2019. The intent is that these satellites will work alongside ground-based receivers to create a global broadband network, with the humanitarian aim of making the Internet accessible for people throughout the world. However, low Earth orbit satellites like the ones in Starlink often appear
In response, the third round of 60 Starlink satellites, which SpaceX launched on 7 January 2020, included some satellites with a special anti-reflective dark coating. The IAO astronomers set out to compare the reflectivity of this modified satellite with the “standard” STARLINK-1113 version using the Murikabushi scope’s MITSuME system, which allows for simultaneous observations in the green,
Photo of a Starlink launch, showing a bright streak across the night sky. New lights in the sky A Starlink launch. (Courtesy: SpaceX, CC BY-NC 2.0)
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