There is nothing astronomers love more than playing with a fun new telescope. We dedicate conference sessions to them, tell everyone who will listen about all the cool science we’ll be able to do with them, and bite our nails when they launch into space. Modern telescopes are one way that we continue the age-old practice of looking up at the night sky and doing science about it. But while we might want to focus on the wonder of astronomy, it can be far too easy to ignore a fact that should be unignorable: we do astronomy on a planet. We humans are part of our natural environment, and our actions have an impact on it. Just like we might think about how we can take better care of the environment by moving away from fossil fuels or by advocating for dark skies, it’s also important to make sure the instruments we use to do science don’t have an adverse impact on the planet we live on.
Luckily, we’re already thinking about how to solve these problems! The next generation of telescopes is being developed with sustainability in mind, and people like Dr. Laurane Fréour are at the forefront. Dr. Fréour is a postdoctoral researcher at the University of Vienna, where she’s ensuring that the proposed Wide-field Spectroscopic Telescope (WST) is designed to operate in an environmentally friendly way as much as possible.
Working towards greener telescopes
If it’s built, WST will be a 12-meter class telescope equipped with both a multi-object spectrograph and an integral field spectrograph, with hundreds of detectors across the two. Its science goals cover everything from mapping the Universe’s large-scale structure to studying the origins of the elements to finding gravitational wave sources. WST’s field of view would cover a large portion of the sky, but it would also be able to quickly follow up on transient sources detected by other telescopes, such as supernovae or gravitational waves. All this would generate a huge volume of data. “The idea is to try to understand what environmental impact this would have, and how do we deal with data centers – where do we try to build them, which type of data we save, which type of data we accept not to save or to save in a place that is maybe not accessible that easily,” Dr. Fréour explains.
Data storage isn’t the only way telescopes can impact their environment, though – we also have to consider how the telescope would actually be constructed. Dr. Fréour uses a software called SimaPro to model the environmental impact of several design options for WST’s instruments. This includes which raw materials are used, how materials are extracted, how and where they are processed, and how they operate within the final instrument.
“I focus really on the design of instruments and how we can try to incorporate the carbon footprint as a trade-off parameter,” she says. When designing an instrument, the focus is typically on maximizing scientific performance and minimizing cost. Now, for the first time, the field of astronomy is beginning to consider the environmental impact of those choices as well.
“What we tried to understand when I started with the position is where would my work have the biggest impact, […] but it’s very hard to know until you compute the numbers,” Dr. Fréour explains. One “hot spot” she found is, ironically, the cooling system. WST’s detectors would need to be cooled to extremely low temperatures, 24/7, in order to work properly, but this requires a lot of energy. Dr. Fréour considered two designs for cooling systems: a traditional cryogenic coolant system that uses extremely cold fluids (such as liquid nitrogen) to cool the detector, or a more sophisticated CO2 extraction cooler. She was able to provide a “life cycle assessment” about the environmental impact of each system over its entire lifetime, considering its CO2 output as well as things like whether its production and use release chemical pollutants, or whether its raw materials include scarce minerals that need to be conserved, in order to help make a decision about which system to use in the final telescope design.
Making change within the field
Dr. Fréour’s journey into climate advocacy began during her Ph.D., when she developed a course on sustainability in academia. Along with three other doctoral students in her interdisciplinary program, she also developed the PLEES index, which quantifies the impact of a changing climate on a psychological, social, and economic level. This work was even incorporated into her Ph.D. thesis, where she drew connections between the methods used to develop the PLEES index and the large volumes of data necessary to study globular clusters.
Working in sustainable astronomy “has a lot of momentum right now, so I would really definitely encourage students or anyone with some interest to look into it”, she says. She urges students and young people to talk with their colleagues and friends about the climate, and stresses that grassroots initiatives can lead to real change. Organizations like Astronomers for Planet Earth have plenty of resources to help brainstorm ideas and organize solutions, and discussions with the people around you can lead to surprising places! The University of Vienna’s Astrophysics department sustainability committee grew organically from the discussion after a presentation Dr. Fréour gave in 2023, and has already implemented a pilot project subsidizing researchers who choose to take the night train for work travel rather than flying.
It’s easy to think that there’s nothing we can do about climate change, that individual actions mean nothing, and that activism is pointless in the face of institutional resistance. It’s also patently false. Momentum is shifting, both on a wider scale and within astronomy itself. Sustainability is part of the selection criteria for the next generation of telescopes, and the fact that this category is considered important enough that WST is not the only ESO Horizons project to employ people specifically with this criterion in mind is encouraging. With work like Dr. Fréour’s, we’ll be able to look up at the stars from our pale blue dot for many generations to come.
Astrobite edited by: Will Golay
Featured image source: Suchitra Narayanan
This post is part of our Earth Week coverage for 2026, centered on the theme of “Green Telescopes for the Pale Blue Dot”, and is a part of our Climate Change Series. If you’re interested in reading more about the work that goes into developing more sustainable instrumentation, other articles are here on our Earth Week x 2026 page. Last year’s Earth Week coverage, on the topic of dark skies advocacy, can be found here.
