The increasing number of satellites circulating in low orbit seriously affects the observations of astronomers. As a result, the International Astronomical Union (IAU) announced the creation of a new center to protect the interests of the scientific community.
With falling costs in space, satellite constellations are legion
The prices for space launches and the manufacture of satellites have never been lower, and the private sector is benefiting greatly. More and more objects are sent into low orbit, with a rate that should even accelerate in the coming years. SpaceX’s Starlink constellation already has more than 1,400 satellites in orbit, with thousands more expected to join.
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The British company OneWeb has launched hundreds of satellites, and Amazon’s Project Kuiper is also preparing to send more than 3,000 to bring quality Internet to the most remote regions of the world. While the European Commission also wants to develop its own constellation, China recently announced that it plans to launch nearly 13,000 communication satellites into Earth orbit.
This certain enthusiasm for low Earth orbit, which goes up to 2,000 kilometers in altitude, has harmful repercussions for scientists, despite the promises of manufacturers who do everything to prevent their satellites from altering the observations of astronomers, like the visor added by SpaceX on its satellites to prevent them from reflecting the Sun.
The Starlink constellation already has more than 1,400 satellites. Photography: ANIRUDH / Unsplash
Astronomy is directly affected by the presence of satellites
A study published on January 15 in the journal Astrophysical Journal Letters looked at the impact of the Starlink constellation on 300,000 images taken by an instrument at the Palomar Observatory in Southern California. It demonstrated that the number of corrupted images increased 35 times between November 2019 and September 2021.
Satellites, due to their presence in large numbers in the sky, affect the optical observations of astronomers by appearing directly on the images, but they also have consequences on radio astronomy, which consists of forming images using radio waves rather than via light emitted by objects. Thus, the telecommunications signals emitted by the satellites tend to stifle those emanating from distant stars, in particular because they can be ” millions of times more powerful » that the latter, explains to the wall street journal Philip Diamond, chief executive of the Square Kilometer Array, a radio telescope project that began construction in 2021.
” It’s a big problem. Astronomy is essential to our exploration and use of space, to deep space navigation, to planetary defense against asteroids, and to our knowledge of the Earth, the solar system, and the Universe. And observing the night sky is central to who we are as human beings. To lose this is a loss to every person in the world said Jessica West, senior space security researcher at Canada’s Project Plowshares Institute, to Gizmodo.
For example, satellite interference could prevent astronomers from detecting a dangerous asteroid.
A center to counter the problem
In order to reduce the impact of satellites present in low orbit on astronomy, the International Astronomical Union has decided to set up a “ center for dark sky protection from satellite interference “. This will be managed by NSF’s NOIRLab, the US center for ground-based optical astronomy, and the SKA Observatory (SKAO), an intergovernmental organization headquartered in the United Kingdom responsible for set up the world’s most powerful radio telescope arrays in Australia and South Africa.
” The International Astronomical Union is deeply concerned about the increasing number of satellite constellations launched and planned, mainly in low Earth orbit. The UAI adheres to the principle of a dark and radio-silent sky, not only because it is essential for advancing our understanding of the Universe of which we are a part, but also for the cultural heritage of all humanity and for the protection of nocturnal wildlife writes the Union in a statement.
The Center will bring together astronomers, satellite operators and regulators to act as a bridge between different parties. Goal : “ coordinate the efforts and unify the voices of the worldwide astronomical community regarding the protection of dark and quiet skies from interference from satellite constellations “.
” This is not about pitting satellites against astronomy, but rather about how to reconcile the different needs, interests and values that coexist in outer space, including those that are less powerful. This requires open dialogue and coordinated, collective action. The international community of astronomers is showing us how. And the world is listening. This is a critical moment for the governance of space “says Jessica West.
Given the frenetic pace of space launches, it is to be hoped that this solution will be viable and will satisfy each of the parties concerned… Even if it seems very unlikely that the private sector will agree to reduce its presence in low orbit or even to slow down its rate of launches.