Aerodynamic Astronomy: Extremely Large Telescope Tackles Wind Tunnel

Engineers with the European Southern Observatory (ESO) are conducting wind-tunnel tests for the astronomical organization's Extremely Large Telescope (ELT), a massive new telescope scheduled to begin scanning the cosmos in 2024. But why would you need wind-tunnel tests for a telescope? There's a simple answer: size.

When complete, the ELT dome will stand almost 262 feet (80 meters) high atop Cerro Armazones, a 1.8-mile-high (3 kilometers) mountain in the Sierra Vicuña Mackenna section of the Chilean Coast Range in the Atacama Desert, where the instrument will face rigorous winds. [The Biggest Telescopes on Earth: How They Measure Up]

"These conditions present an engineering challenge, making wind-tunnel tests vital," ESO officials explained in a new video.

European Southern Observatory engineers put a model of the Extremely Large Telescope through a wind-tunnel test to ensure the telescope can withstand the harsh mountaintop environment in Chile's Atacama Desert. (Image credit: ESO)

During the tests, a model of the ELT faced blustery conditions in a wind tunnel at the Polytechnic University of Milan in Italy. It was plastered with sensors to measure the structural load it could face. 

"The wind-tunnel test is developed to reproduce the conditions that the ELT will face when it's operational," said engineer Luca Ronchi in a blog post, "so, basically, it's about reproducing the dome and telescope on a smaller scale (made of glass-fiber-reinforced plastic), equipping it with sensors, calibrating these sensors, placing the object in the wind tunnel and — according to the established and agreed-upon test program — reproducing the conditions that the ELT will actually face on top of Cerro Armazones."

When complete, the Extremely Large Telescope will use a colossal, 128-foot (39 m) primary mirror, made up of 798 hexagonal mirror segments, to survey the universe like never before. 

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Jasmin Malik Chua
Contributing Writer

Jasmin Malik Chua is a fashion journalist whose work has been published in the New York Times, Vox, Nylon, The Daily Beast, The Business of Fashion, Vogue Business and Refinary29, among others. She has a bachelor's degree in animal biology from the National University of Singapore and a master of science in biomedical journalism from New York University.