A 600 m 2 array of 6.5 m telescopes at the lunar pole

• Published in: Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
• Main Author: Angel, Roger
• Other Authors: College of Science, University of Arizona
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Royal Society 2024
• Subjects: South Pole; South pole
• Online Access: http://dx.doi.org/10.1098/rsta.2023.0076; https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.2023.0076; https://royalsocietypublishing.org/doi/full-xml/10.1098/rsta.2023.0076

The proposed lunar telescope for optical and infrared astronomy aims at very large aperture, 600 m 2 , at a fundable cost. It comprises an array of 18 separate telescopes, each of 6.5 m aperture. The 200 m diameter array will be located within 1/2° (15 km) of a lunar pole on approximately level ground, with a perimeter screen deployed to provide shade and cooling to cryogenic temperature. The 500 m diameter screen will allow unobscured access down to 8° elevation. All 18 telescopes will reflect light into a central beam combiner to form a single image covering wavelengths from 0.4 µm to 10 µm. The initial instrument complement will include high-resolution and multi-object spectrographs to exploit the single combined field of view of two arcminute diameter, with the diffraction limited resolution of 6.5 m aperture. Scientific applications include the search for molecular biosignatures in transiting exoplanets, and the study of galaxy evolution using red-shifted spectra to beyond z = 10. The array cost, including delivery to the Moon by SpaceX Starship for installation using lunar base infrastructure, is around $10 billion, similar to that of the 25 m 2 JWST. To test the concept, first a single prototype 6.5 m unit would be operated at the lunar south pole. This article is part of a discussion meeting issue ‘Astronomy from the Moon: the next decades (part 2)’.