Satellite swarms harm astronomy. Here is how the researchers fight

In the next few months, from its body over a mountain in Chile, the Vera C. Rubin Observatory will start wiping the universe with the largest camera that has ever built. Every three nights, a map of the entire southern sky, full of stars, galaxies, asteroids, and superior drawing – will produce bright satellites destroy some view.

Astronomers have not worried very much about the formulation of satellite photographs when they started making plans for the observatory for more than two decades. But with the increasing congestion of the area surrounding the land, researchers have to find new ways to deal – or lose precious data from Robin and hundreds of other betting.

The number of satellites operating in the past five years has risen to about 11,000, most of which are due to the towers of orbits that provide internet connection all over the world (see “increase in the satellite”). Only one company, Spacex in Hawthorne, California, has more than 7000 operating satellites, all of which have been launched since 2019; Oneweb, a London Satellite Communications Company, has more than 630 satellites in a constellation. On paper, dozens to hundreds of other thousands of a variety of companies and countries are planned, although all these things are likely to be launched.¹.

Satellite plays an important role in linking people, including bringing the Internet to remote communities and emergency respondents. But the increasing number can be a problem for scientists because satellites interfere with the Earth’s astronomical notes, by creating bright lines on images and electromagnetic interference with radio telescopes. The satellite mutation also offers other threats, including adding pollution to the air.

When I fired the first curtain links, some astronomers warned of existential threats to their discipline. Now, researchers in astronomy and other fields work with satellite companies to help identify effects on science – and society. “There is increasing interest in cooperation and finding solutions together,” says Juliana Rotola, political researcher at Santana College for Advanced Studies in Pisa.

The timing of things properly

The first step to reduce satellite overlap is to know when and where the satellite will pass over an observatory. “The goal is to reduce the surprise,” says Mike Bell, an astronomer at the Imperial College London.

Cleaning space: How can satellites and telescopes live together

Before the launch of Starlinks, astronomers did not have any central sign of satellite tracking. Now, the International Astronomical Union (IAU) has a virtual center to protect the dark and calm sky from the overlap of the satellite constellation (CPS), which works as an information center that they volunteer, including Peel and Rotola, their time.

One of the center’s tools, called SatcheckerIt depends on a general database of satellite orbits, which are fed by information from observers and companies that follow things in space. Astronomers can use Satchecker to confirm the satellite that passes the public expenditures during their notes. The tool is not perfect. Air clouds and deliberate maneuvers can affect the satellite position, and the public database does not always reflect the latest information. For example, the Bluewalker 3 satellite from the AST Spacembile telecom company was launched in Midland, Texas, in 2022 and was sometimes brighter than most of the stars; However, the uncertainty in his position was so great that astronomers have had difficulty predicting whether they would be in their field of night notes.².

Tools such as Satchecker help the telescope players avoid problems by allowing them to target a different part of the sky when the satellite passes over the moon or simply by stopping notes during its development. Astronomers will help if Satchecker has more accurate information about satellite sites, but there are restrictions on improving the system. Satchecker data comes from the American space power, which depends on a global network of sensors that track or orphans the orbit and issue updates on satellite sites as they increase several times a day. The frequency of these updates is limited to factors such as the number of times that the sensor can be observed and whether the sensor can distinguish between what is seen.

Currently, satellite lines are a relatively simple issue for telescope operators. But the problem will grow as the numbers of satellites continue to increase significantly, which means that more monitoring time will be lost, and this problem will be enlarged for Rubin.

Fix the fonts

Robin, which costs $ 810 million to build, is a unique condition because she is wiping large areas of the sky repeatedly – which means that he can discover changing phenomena quickly such as incoming asteroids or cosmic explosions. Astronomers do not want to be deceived by passing satellite, as happened in 2017 when researchers discovered what they believed was an explosion of rays-flashes with high energy-from a distant galaxy, but it turned out to be sunlight that reflects a piece of space hats.

A special spacecraft, Mont Moon, the first pictures of Blue Ghost on the moon

The powerful Robin camera, along with the 8.4 -meter telescope, will take about 1,000 night widths of the sky, each of which is about 45 times in the moon completion area. These are extensive pictures of the sky from any optical observatory that has been taken at all. Simulation operations indicate that if the numbers of satellites in the orbit of the low-Earth increases to about 40,000 over the past 10 years of Robin-which are not due-at least 10 % of their forms, and the majority of those taken during the twilight will contain,³.

Spacex take early steps to try to reduce the problem. By working with Rubin astronomers, the company has tested changes to Starlinks’s design and attitudes to try to preserve its brightness under the target threshold. Amazon, retail giant and technology based in Seattle, Washington, is tested to dilute the model satellite of the planned constellation of Koyber. Such changes reduce, but do not spend, the problem.

To reduce satellite overlap, astronomers Robin create monitoring tables to help researchers avoid certain parts of the sky (for example, near the horizon) and at certain times (such as a twilight)⁴. Because when they could not avoid satellites, Robin researchers merged steps into their data processing pipeline to discover and remove satellite lines. Astronomers say that all these changes mean less time in making science and more time to process data, but must be done. “We are really looking to get data from Robin and see how he appears,” says Bell.

For other posts, Iau CPS is working on tools to help astronomers identify and correct satellite lines in their data. One is a new database of collective notes called satellite brightness a resultThe beta test is currently underway and is planned for the broader release in the coming months. This will help scientists work back – they may see something confusing in their previous notes and be able to solve them, says Bell.

“It is definitely a very valuable tool” because it is one of the few who have free data. As a experimental test, Langbroek added a number of entries for registration, including NASA’s solar sail measurements that change in brightness while declining across space. He says that moving forward in moving forward, the result will be very useful if many astronomers contribute with high -quality notes in the database, thus building a resource over time.

Set

Astronomers who work in the radio part of the electromagnetic spectrum face additional challenges when it comes to satellites.

The launch of Spacex highlights a threat to astronomy from “Megaconstelles”

Large radio telescopes are usually found in remote areas, to be the maximum extent of mobile phone maws and other technological infrastructure that leak radio emissions. But satellites cannot be avoided. “If the signals come from the sky, they are always there,” says Federico Di Vruno, an astronomer at the Iau CPS Observatory.