Planned deployments of up to 1.7 million satellites could cause “devastating consequences” for astronomy, according to new research from the European Southern Observatory (ESO). The study, published in Astronomy & Astrophysics, warns that these massive constellations pose an “existential threat” to telescopes by making the night sky significantly brighter and obscuring celestial views.
How many satellites are planned for Earth’s orbit?
The number of satellites currently orbiting Earth has reached approximately 14 000, largely due to the expansion of Elon Musk’s Starlink internet constellation. However, researchers warn this is only the beginning of a massive orbital expansion.
SpaceX has announced intentions to launch more than one million satellites by 2028. These satellites are intended to serve as data centers to support the growing artificial intelligence industry.
Other major projects contributing to the projected 1.7 million total include:
- E-Space: The “Cinnamon” project aims to add hundreds of thousands of satellites.
- Chinese Constellations: The CTC-1 and CTC-2 projects involve hundreds of thousands of additional units.
- Reflect Orbital: A US start-up planning to launch 50 000 large satellites equipped with mirrors to reflect sunlight back to Earth.
Why do these constellations threaten astronomical observations?
Large, bright satellites interfere with the ability of ground-based telescopes to capture clear images of the universe. Olivier Hainaut, an ESO astronomer who led the study, told AFP that when a satellite crosses a field of observation, it creates a bright streak that “zaps” whatever is behind it.
Hainaut noted that while the current 14 000 satellites are still manageable, the jump to 1.7 million would create significant operational problems for astronomers.
The impact is particularly severe for advanced equipment like the new Vera C. Rubin Observatory in Chile. Researchers determined that almost all images captured by the observatory’s massive camera could be rendered unusable by the increased light pollution.
The 50 000 satellites planned by Reflect Orbital could make the entire night sky up to four times brighter than it is today.
What is the expected impact on the night sky?
The research suggests the night sky will lose its clarity. Hainaut warned that whether observing from France, the Sahara Desert, or Chile, the sky would no longer appear clear, instead resembling the sky seen in city suburbs.
In heavily light-polluted urban areas, the ESO states that these satellites might become the only visible “stars” in the night sky.
Reflect Orbital’s technology presents a specific challenge. Hainaut said that even when the satellites’ mirrors are not pointed directly at an observer, the light they scatter will make each satellite as bright as Venus, the “morning star.”
How can regulators mitigate the threat?
To preserve the ability to explore the night sky, researchers are calling for strict limits on orbital density. Hainaut proposed a maximum limit of 100 000 satellites orbiting Earth. He also suggested that any satellites deployed must be made dim enough to remain invisible to the naked eye.
The responsibility for these decisions now rests with government agencies. Both SpaceX and Reflect Orbital are currently awaiting decisions from the US Federal Communications Commission (FCC) regarding their constellation launch applications.
The ESO’s institutional affairs officer, Betty Kioko, stated that the new study will form the basis of the ESO’s response to these applications. “For optical astronomy, this is an existential threat, and we hope that the regulators will share that view,” Kioko said in a statement.
What are the broader environmental consequences?
The implications of massive satellite constellations extend beyond astronomy. The loss of dark skies has been linked to the disruption of biological clocks in both humans and animals, which can interfere with various ecosystems.
There are also environmental concerns regarding the energy required to launch nearly two million satellites. Additionally, the sheer volume of objects increases the risk of “Kessler syndrome,” a dangerous chain reaction where space debris crashes into other objects, creating more debris.
Frequently Asked Questions
How many satellites are currently in orbit?
There are currently about 14 000 satellites in orbit.
What is the maximum number of satellites researchers recommend?
The ESO recommends a limit of 100 000 satellites to protect astronomical observations.
Which agency regulates these satellite launches in the US?
The Federal Communications Commission (FCC) is responsible for reviewing launch applications.
What is Kessler syndrome?
It is a theoretical scenario where space debris causes a chain reaction of collisions, making certain orbits unusable.
Stay informed on the latest developments in space technology and environmental policy. Subscribe to our newsletter or leave a comment below with your thoughts on orbital regulation.
