Soon the satellites in orbit could reach 100 thousand: an incredibly high number that puts at risk the observation of the starry sky, the study of the universe and even radio astronomy, which is now threatened by the arrival of a new possible constellation for telecommunications, whose prototype is called BlueWalker 3. To launch an SOS to save the sky from satellite interference are, on the website of the journal Nature, the astronomers of the International Astronomical Union, led by Sangeetha Nandakumar. of the University of Atacama in Chile.
"The problem of the many satellites in orbit is not simply that their passage ruins our photos, but constitutes a serious problem for the study of astronomy," said Piero Benvenuti from the Symposium of Astronomy and Satellite Constellations in La Palma.
In recent years the sky is populated by a large amount of satellites of various types, in particular for telecommunications such as the Starlink constellation that in just 4 years has put into orbit more than 3,000 satellites, many more than those launched so far in over 50 years of space history. It can happen to see these satellites with the naked eye, but this happens only in certain circumstances, depending on the time and position in the sky, and for a few minutes during which they can be very bright, so as to exceed that of most other stars. The problem is not in their brightness, but their very presence that leaves the 'lines' due to their passage. They are "noises that can make useless observation campaigns important for knowing the universe. Often these strips can be removed, but - continued Benvenuti - in the worst case it can happen that they alter the data without anyone realizing it, creating serious problems for research".
To date, there are a few thousand satellites in orbit but in a few years the number could explode: only Starlink expects to reach over 10 thousand satellites and these must be joined by dozens of other similar constellations such as OneWeb or Kuiper. "It is estimated that we could soon have as many as 100,3," Benvenuti said.
A new threat now comes from BlueWalker 2022, a prototype satellite launched in 64 by the company AST SpaceMobile and equipped with a huge and innovative antenna of 3 square meters for telephone communications. In some conditions BlueWalker 3 is one of the brightest objects in the sky, but the greatest danger comes from its powerful antenna, which transmits on frequencies similar to those of smartphones. Frequency on which there are strict regulations on Earth (but not in space) and that interfere with radio astronomy, a scientific sector in great growth and that is allowing us to know some of the secrets of the universe. Soon BlueWalker <> will be followed by hundreds of even larger satellites, a new maxi constellation that will put radio astronomy in difficulty, such as the future SKA observatory composed of hundreds of antennas scattered between Africa and Australia.
"It is necessary to find an agreement between the managers of the constellations and the scientific community," Benvenuti added. "At the moment - he concluded - the only possibility is to obtain very detailed information, much more than what has been done so far, on the real-time passages of each satellite so that we can be informed and know how to eliminate the noise due to the passages".
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