The introduction of 26,000 new giant satellite constellations could have a major impact on ground-based astronomy, according to a new study commissioned by the European southern observatory. Over the next few years, the number of satellites visible to the naked eye will triple as SpaceX, OneWeb, and amazon pursue orbital projects.
The progress of human technology seems to be inextricably linked with the increasing pollution of the natural environment. On earth, industrialization has changed the global climate with potentially profound and enormous consequences, and the advent of modern consumerism has polluted the oceans with plastic waste. As more and more people mastered the orbit, the space environment began to be damaged by human pollution. The proposed giant satellite constellation, for example, could see nearly 26,000 satellites launched into low-earth orbit in the next few years, compared with about 5,000 satellites that are still in orbit.
The giant satellite constellation is a large collection of satellites flying in formation in low earth orbit. SpaceX is already building its Starlink project, which Elon Musk hopes will one day provide low-cost Internet access worldwide. The company is busy launching the satellites on its falcon 9 rocket. SpaceX is not the only company hoping to use the satellite fleet to provide Internet services. OneWeb also wants to create an orbiting network of hundreds of satellites, as does the global giant amazon.
The proliferation of satellite technology and the emergence of giant satellite constellations has not only produced physical contamination in the form of failed satellites, but also, at worst, debris from orbital collisions. It could also seriously interfere with astronomical observations. These swarms of detectors relentlessly pass through the line of sight of powerful telescopes that capture detailed observations of cosmic objects, reducing the quality of the data set.
The scientists behind the latest study have modeled the impact that the giant satellite constellation could have on visible and infrared observations of ESO telescopes, such as the very large telescope in Chile’s atacama desert. The paper takes into account a number of factors and different ways of looking at the sky with a telescope.
The results show that observations dependent on short-term exposure are affected by satellite photobombs only 0.5% of the time, mostly in the twilight. At this time, after dusk or before dawn, astronomers are actively observing the night sky, but there is enough sunlight around the curve of the earth to illuminate the mass of metal detectors that flit overhead. In the twilight, telescopes that require longer exposures (about 1,000 seconds) will be affected about 3 percent of the time.
The wide-area used to stare continuously into the night sky for fleeting events such as new stars, long-exposure observations will be most affected by satellite constellations. For example, the national science foundation’s vera rubin observatory will be affected by satellites 30 to 50 percent of the time, depending on the time of year.
The study also mentions two main ways in which astronomers can try to mitigate the damage caused by satellite swarms to their observations. The first is to arrange its telescopes to capture the sky when there is no satellite in a given area. Satellite paths are predictable, so this is a viable technology. However, it does not apply to every type of observation. For example, it may be impossible to avoid satellite contamination when long, wide-field exposures are required. The second method involves interrupting the telescope’s guard by precisely determining when a bright satellite is passing through the field of view and closing the shutter before the moment of contact. This would be a challenging technique and would not work at all for wide-field observations.
On the industrial side, manufacturers can darken the satellite’s surface to reduce reflection. SpaceX has tried this approach on one of its Starlink satellites, though it would have to be widespread to be effective. The study also touched on the impact of giant satellite constellations on the public’s view of the night sky. At mid-latitudes, 1,600 satellites will appear above the horizon, the researchers say. This could result in a tripling of the number of satellites visible to the naked eye in the night sky compared to today.
The study aims to provide a simple assessment of the impact of satellite clusters on scientific observations, rather than a comprehensive study of potential damage. To arrive at a conservative estimate, researchers must make some educated guesses about important elements, such as the distribution and brightness of satellites. The authors note that their results “could go wrong on the pessimistic side” and that further research using more complex models will help reveal the nature of future disturbances and explore their impact on radio, millimeter and submillimeter wavelength observations.
The paper is in the journal astronomy and astrophysics.