SpaceX's New Direct-To-Cell Starlink Satellites Are Way Brighter Than the Originals

According to a recent study, SpaceX's new Starlink direct-to-cell (DTC) satellites are nearly five times brighter than traditional Starlinks due to their lower orbit. While these satellites offer the promise of widespread connectivity, their increased brightness poses challenges for astronomical observations, prompting SpaceX to consider applying brightness mitigation techniques. Space.com reports: The higher luminosity of these DTCs compared to regular Starlinks is partly because they circle Earth at just 217 miles (350 kilometers) above the surface, which is lower than traditional Starlink internet satellites, whose altitude is 340 miles (550 kilometers), the study reported. [...] At the time the study was conducted, SpaceX had not yet applied its routine brightness mitigation techniques to the DTCs, such as adjusting their chassis and solar panels to reduce the portion of spacecraft illuminated by the sun, study lead author Anthony Mallama of the IAU Centre for the Protection of Dark and Quiet Skies from Satellite Constellation Interference (IAU-CPS) told Space.com. SpaceX began applying brightness mitigation techniques to regular Starlinks in 2020, after astronomers voiced serious concerns about the satellites' trails streaking across telescope images, rendering them unusable. Prior to launch, the company now applies a mirror-like dielectric surface to the underside of each Starlink chassis, to help reflect sunlight into space rather than scattering it toward Earth. Post launch, the company adjusts spacecraft chassis and solar panels to further reduce luminosity. Together, these techniques are very effective, reducing Starlink satellites' brightness by a factor of 10, Mallama said. If SpaceX applies these brightness mitigation techniques to the DTCs, which are nearly the same size as the regular Starlinks, the DTCs would still be 2.6 times brighter than their traditional counterparts, Mallama and his colleagues reported in the recent study, which was reviewed internally by IAU-CPS and posted to the preprint server arXiv last month. However, while DTCs are brighter objects, they move at a faster apparent rate and spend more time in Earth's shadow than regular Starlinks, which would offset some of their negative impact on astronomy observations, the study noted. "I see it as a tradeoff in parameters rather than an absolute better/worse kind of situation," John Barentine, a principal consultant at Arizona-based Dark Sky Consulting who was not involved with the new study, told Space.com.

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