Is the Moon the future of infrared astronomy?

Infrared astronomy, particularly in spectroscopy, could benefit in a decisive way from an implementation of telescopes on the Moon since the largest telescopes on Earth are practically limited to 40 m and in space to 10 m. On the Moon, a collector larger than on Earth becomes conceivable, thanks to the low gravity and the absence of wind, in having the advantages of space. Passively cooled in the bottom of a permanently shadowed crater at the northern or the southern pole, it could reach unprecedented spectral sensitivity on a large part of the infrared domain, making possible spectral analysis of the most primitive galaxies and of the terrestrial exoplanet atmospheres. A project aiming at the detection of the weak cosmic microwave background spectral distortions is also presented. Several identical 1.5 m cryo-cooled telescopes at 2.5 K to fit in a launcher, with an imaging Fourier transform spectrometer in each unit, deposited in a cold crater and pointing in the same direction in lunar survey mode, would build for this fundamental goal the equivalent of a large telescope at an extremely low temperature. Last, the feasibility of these projects is discussed. This article is part of a discussion meeting issue ‘Astronomy from the Moon: the next decades'.