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SpaceX upgrades Starlink to reflect less light, can't launch without its Starship

A dazzling problem

SpaceX's has big claims that its second-generation Starlink broadband internet satellites will slash light pollution on Earth, but there's one big catch: they're apparently too heavy to launch.

SpaceX satellites have drawn the ire of astronomers since their deployment in 2019. While they may not be completely ruining the images taken by sensitive astronomical equipment, they've become an annoyance to professional and amateur stargazers alike.

The issue is that they catch the Sun's light and reflect it, appearing as pinpoints or streaks of light in images of the heavens, obliterating from view stars and other objects behind them.

A brightness mitigation report [PDF] published by SpaceX last week states that the Musk-owned rocket business developed a couple of light-dimming concepts for the first generation of its Starlink satellites, including sun visors and RF-transparent mirror films. The former failed, while the latter is being improved for Starlink 2. 

The upgraded satellites are equipped with three bits of technology the rocket company said will improve their brightness mitigation: dielectric mirror film, solar array mitigations, and good old-fashioned black paint.

The film will cut the observed brightness from Earth by 10X, SpaceX claims, and will cover the bottom of the satellites. In addition, it'll offer the film as a product to other satellite operators "at cost," to increase brightness reduction elsewhere.

To mitigate light bouncing off the satellites' solar panels, SpaceX has made them more absorbent by adding a dark red inter-cell backing material. This has the side effect of reducing efficiency and increases current operating temperatures, but does cut back on the Earth-side glare.

In the second-gen hardware SpaceX will also use internally developed low-reflectivity black paint on more components. The black material has "five-times lower specular peak compared to the darkest available space stable paint," it said.

"SpaceX's goal is to make its second-generation satellites invisible to the naked eye when they are on station serving users," the company said.

One massive problem

Getting them into station is currently impossible, however, because the second-generation satellites are too large and heavy for anything but SpaceX's yet-to-launch Starship to get them into orbit. 

"We need Starship to get to orbit because it's the only thing that can carry the Starlink 2 satellites," Musk said in an interview on YouTube channel Everyday Astronaut. Starlink 2 satellites are massive, measuring about 1.25 tons and 7 metres long, according to Musk, who said SpaceX's Falcon rocket has neither the mass nor the volume to get into orbit with a bunch of Starlink 2 satellites to deploy (and they do need to blast off in collections to make the launches worthwhile.)

Starship itself has yet to make an orbital flight; Accidents and 75 operational shortcomings [PDF] identified by the FAA in June make it unlikely it will take to orbit anytime soon. Musk's planned launch dates continue to come and go without a firing.

On the whole though, space watchers seem to welcome SpaceX's efforts. The Register caught Piero Benvenuti, the International Astronomical Union's Centre for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference on his way to a flight, and he was very happy with developments.

"This is a real demonstration of corporate good citizenship, representing a significant investment of engineering resources in both hardware and operational modeling to reduce reflected sunlight hitting telescopes on the ground," he said, on his way to the IAU's General Assembly.

"SpaceX sharing their technical approaches, accepting trade offs toward the goal of reducing brightness, offering to sell a darkening film to other operators at cost, and publishing accurate and timely state vectors all promote the spirit of cooperation that is the centerpiece of CPS goals for interacting with industry."

In the meantime, they'll have to settle for software that can remove satellite streaks, and they're probably going to have to do so for a while, until Starship gets off the ground. ®

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