2023-10-02 15:00:26
One Studywhich has now been published in the journal “Nature”, shows that the “BlueWalker 3” satellite can shine up to a hundred times brighter than recommended by researchers.
The satellite in question was developed by the US company AST Space Mobile and launched into space on September 10, 2022. Around two months later, the 64 square meter antenna of the prototype of the telecommunications satellite type was deployed in near-Earth orbit between 500 and 600 kilometers, of which around 100 examples will be in orbit in the future in order to provide the world with an additional broadband Internet service from there take care of.
“BlueWalker 3” has since been considered one of the brightest artificial objects in the night sky. A team consisting of researchers and amateur astronomers wanted to find out exactly how bright. To do this, they aligned large and small telescopes from Chile, the USA, Mexico, New Zealand, the Netherlands and Morocco towards the satellite. The analysis now available from the team led by the first author Sangeetha Nandakumar from the Universidad de Atacama in Chile and the Austrian astrophysicist Siegfried Eggl from the University of Illinois in the USA comes to astonishing findings.
“String of pearls” made of satellites
Als Vorstandsmitglied des „International Astronomical Union Centre for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference“ (IAU CPS), Eggl’s job is to determine the brightness of newly launched satellites regardless of the manufacturer’s information, the scientist, who researches at the interface between space travel and astronomy, told the APA. The problem with reflected sunlight from satellites is becoming more and more virulent and is now causing difficulties for high-tech research with highly sensitive detectors, but also for amateur astronomers.
Michael Tzukran
BlueWalker 3
“Since the SpaceX company launched thousands of ‘Starlink’ satellites, many ‘night owls’ have noticed this, especially shortly following the launch of the satellites when they move over the horizon in a ‘string of pearls’. “But that’s just the beginning,” says Eggl. The current number of around 7,000 to 8,000 satellites in orbit will “increase to over 40,000” through SpaceX’s ambitions alone.
“BlueWalker 3” well above the pain threshold
No fewer than around 20 countries are currently planning to install their own Internet access in space. Then there would be significantly more artificial celestial bodies on the move than visible stars. This becomes an even bigger problem for astronomers who work in the radio frequency range, because here every satellite can appear as bright as the sun, says Eggl. Since there are still no laws to protect the night sky, the IAU CPS, together with satellite operators, is trying to find a solution so that the reflections from the devices do not reach the astronomical pain threshold of seven magnitudes (from values above seven, a satellite is no longer accessible to the naked eye recognize; note).
In any case, “BlueWalker 3” is well above this pain threshold: in its brightest phase during the observation period, the satellite reached a magnitude or “apparent brightness” of 0.4. This makes it as bright as Procyon and Achernar, the two brightest stars in the constellations “Little Dog” and “River Eridanus”, respectively. In their work, the study authors recommend that a critical assessment of the impact of satellites on space and the Earth’s environment should be part of the approval processes before launch.
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