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The sun visor can dim the future "Starlink" satellites

wallpapers Tech 2020-07-21
According to foreign media New Atlas, SpaceX has now announced that it will install sun visors on each of the Starlink satellites and allow them to be manipulated in a controlled manner to enable them to observe the astronomy of the night sky in detail. The influence of the family is not so obvious. SpaceX has launched more than 400 satellites to support a satellite constellation that can provide global broadband Internet access in the future.

Bottlenecks faced by giant satellites

The proliferation of satellite technology and the increasing cost of reaching low earth orbit (LEO) have caused many people to express concerns about the impact of "space traffic" on the night sky. With the emergence of giant satellite constellations, this issue has become increasingly controversial. And SpaceX's "Starlink" giant satellite constellation is smoothly becoming a reality, and in the future it can provide high-speed, low-latency satellite broadband worldwide. Of course, it is not ideal to have groups of satellites light bombard the observations of long-exposure telescopes. A recent study published in the journal Astronomy and Astrophysics suggests that the introduction of thousands of new satellites may have a significant adverse effect on ground-based astronomical observations.

"Starlink" satellite launch brings advantages

In a previous "Starlink" launch, SpaceX deployed a satellite full of dark coating as part of an experiment to reduce the satellite's light footprint. According to Space, the test successfully reduced the brightness of the satellite by approximately 55%. However, by dimming the satellites, they also make the probe more likely to overheat, which can lead to failure. This week, SpaceX announced a new set of measures. It is taking a series of new measures to alleviate the risk of light pollution caused by its Starlink satellites. During the ascent period, when the satellite is in the orbit before reaching the orbit, its solar cell array is the main source of light pollution. This is because the satellite uses what SpaceX calls an "open" configuration, in which the array is laid flat in front of the spacecraft relative to the earth's surface to reduce atmospheric drag. At this stage, sunlight will reflect off the main body of the spacecraft and the solar cell array, making it visible from the earth.

Detection of the possibility of reversal satellites

SpaceX is currently exploring the possibility of flipping the satellite when it enters orbit. This will prevent the light from flashing on the battery panel like a mirror, but this technology has certain problems that prevent it from being used all the time. The side of the solar cell array facing the sun will limit the amount of light it can collect and convert into energy. In addition, flipping the spacecraft to maintain this direction will reduce the time that the ground station stays in contact with the spacecraft, because the antenna will periodically point away from the earth. In other cases, two side-mounted star-tracking cameras are pointed directly at the earth and the sun. During these periods, it will be a challenge to accurately read the orbital height of a spacecraft.
"Starlink" satellite with sun visor
When the "Starlink" satellite reaches the target orbit, its solar array is repositioned into a "shark fin" configuration, which will be located above the spacecraft. At this time, the main cause of light pollution is the white antenna used by the spacecraft to communicate with the ground station and relay data. Instead of dimming the antenna, SpaceX chose to install sun visors on the satellite to prevent light from hitting the reflective surface and the white phased array antenna. During the launch, the sun visor will be placed flat on the detector and will be deployed shortly after the launch of the "Starlink". The first satellite with a sun visor will be launched in May, and the company said that all future satellites launched from June will be equipped with sun visors.