Dark skies vital for astronomy in Northern Chile now at risk
Northern Chile is home to some of the most pristine night skies on Earth, thanks to its high altitude, dry climate, and status as one of the least light-polluted regions on the planet. These exceptional conditions have made Chile a global leader in astronomical research, attracting billions in investment and enabling discoveries that expand our understanding of the universe. But this irreplaceable resource is now under threat.
DarkSky International is deeply concerned about the proposed INNA project—a large-scale industrial development that includes renewable energy facilities and export infrastructure. Located just kilometers from some of the world’s most advanced astronomical observatories, the project poses a serious risk to the integrity of these globally significant sites.
While DarkSky supports the transition to renewable energy, the location of such projects must be carefully considered. DarkSky opposes the INNA project in its current location and calls for immediate action to protect northern Chile’s dark skies and safeguard its unparalleled potential for astronomical discovery. The seriousness of this threat has led the DarkSky Board of Directors to issue an official position statement on the INNA project.
Read the full statement: English | Spanish (translated by Paulina Villalobos, DarkSky Board Member, Chile)
What is the INNA project?
The INNA project, submitted by AES Andes to Chile’s Environmental Impact Assessment System (SEIA) in December 2024, proposes a wide-ranging green industrial complex. The development includes a wind farm, solar photovoltaic facility, seawater desalination plant, green hydrogen and ammonia production, and a major industrial port for exports.
This industrial mega-project would be located just 5 to 11 kilometers from the Very Large Telescope (VLT) at Cerro Paranal and the under-construction Cherenkov Telescope Array Observatory-South (CTAO-South)—two of the world’s most advanced astronomical research facilities. If approved, INNA would place heavy industrial infrastructure dangerously close to these observatories, risking serious and irreversible damage to their operation.
Why are Chile’s skies so important?
Chile’s Atacama Desert region offers an almost unmatched combination of dark skies, high elevation, dry air, and atmospheric stability. These conditions make it the ideal place for cutting-edge space research. The European Southern Observatory (ESO) has long recognized this advantage, constructing the VLT, the soon-to-be-completed Extremely Large Telescope (ELT), and supporting Chile as a hub for international astronomy.
These observatories are not short-term installations. They are designed to operate for decades, with lifespans of 50 years or more. Their success depends on the continued protection of the region’s natural darkness.
Beyond their immense contributions to scientific discovery, these observatories play a vital role in Chile’s economy and have positioned the country as a globally recognized hub for astronomy and aerospace. Chile’s leadership in this field is not only a source of national pride but also a cornerstone of its international scientific standing—and it must not be taken for granted.
The INNA project’s threat to astronomical research
Leading scientists, astronomers, and environmental experts have raised serious concerns about the INNA project’s impact on the sensitive observing conditions in northern Chile. Based on research, environmental models, and expert analysis—including findings from the Illumina 3D light pollution simulation—this project poses three key threats to astronomical observation:
Light Pollution: Even low levels of artificial light can interfere with telescopes’ ability to detect faint cosmic signals. Modeling shows that INNA would significantly brighten skies at Paranal—potentially exceeding the combined light emissions of Antofagasta and the Escondida mine if the site is expanded.
Airborne Dust: Construction and industrial operations generate fine particles that scatter light and blur images, reducing the precision of highly sensitive instruments.
Atmospheric Turbulence: Wind turbines and large infrastructure near observatories could disrupt stable airflows, undermining the atmospheric clarity that makes this region ideal for astronomy.
Perhaps most concerning, the INNA project sets a dangerous precedent. Its presence could open the floodgates for additional industrial development in this fragile region, compounding the threat to dark skies far beyond its immediate footprint.
The need to address gaps in Chile’s dark sky protection laws
Chile has made major strides in light pollution regulation. Decreto Supremo (DS) No. 1 of 2022 and DS No. 2 of 2023 have established emission standards and designated Astronomical Areas with lighting restrictions. These laws are models for the world, requiring warm-spectrum lights with low blue light emissions and mandating environmental reviews for projects near observatories.
However, these laws have a critical shortcoming: they assess projects individually and do not adequately address cumulative impacts. The standard threshold for light pollution—10% above natural background—is too permissive. This limit was originally established in the 1970s for observatories, but the International Astronomical Union (IAU) has since updated its recommendations.
Current levels at Paranal and Armazones are below 1%, and even small increases could threaten the sensitive observations required for cutting-edge research, including the search for life beyond our planet.
DarkSky’s position: The project must be relocated
DarkSky International supports the advancement of green energy and responsible development. However, these efforts must be pursued in harmony with the environment—including the natural night sky.
DarkSky opposes the INNA project in its current location. The scientific value and significance of the dark skies surrounding these critical observatories is simply too great to risk. Instead, DarkSky advocates for the following:
Establishing a legally protected buffer zone of at least 50 kilometers around major astronomical observatories in northern Chile.
Setting a strict light pollution threshold of no more than 1% above natural background levels within this zone.
Relocating the INNA project outside this protected area to preserve the integrity of Chile’s astronomical future.
Modeling using the Illumina 3D simulation confirms that moving the project just 50 kilometers farther from observatory sites would maintain current low light pollution levels. The choice is clear: sustainable development and dark sky protection can—and must—coexist.
A call to action
Chile is at a pivotal moment. The INNA project is currently undergoing environmental review, and the citizen participation period is open through April 3. During this phase, all Chilean citizens have the right to submit formal observations about the project’s environmental impacts—including its effect on sky brightness and astronomical research.
To support public engagement, our partners in Chile have created helpful Instagram reels (in Spanish) that explain how to participate in the process:
How to submit observations – Reel 2
DarkSky International urges:
- Rejection of the INNA project in its current location
- Creation of a legally protected exclusion zone around major observatories
- Adoption of stricter cumulative light pollution limits, aligned with international standards—such as the IAU’s recent recommendation to lower the threshold for sky brightness increases near observatories (IAU announcement)
Momentum is growing within Chile. A group of senators has formally called on President Boric to establish protections for dark skies near observatory sites. In support, DarkSky will share its own brightness threshold criteria used in Dark Sky Place certifications to inform national policy discussions.
Protecting Chile’s skies is a shared responsibility. The decisions made today will shape the future of astronomy for decades to come.
….
Stay updated on DarkSky’s work to protect the night. Join our email list to receive e-news updates and our monthly Night Owl newsletter.
