A discussion on infared astronomy - Mid-infrared spectroscopic observations of the Moon

Abstract

Now that space probes have actually landed on the Moon, and man is soon to follow, one might suppose that the need for the development of lunar remote sensing techniques is past. Exactly the opposite is true. It must be remembered that no nation is financially able to support exploration of more than a very small percentage of the total surface area of the moon. Small areas immediately adjacent to a landing site will, of course, be explored in detail. Hopefully, there will be a few traverses made to discover the degree of lateral inhomogeneity of the surface materials. Realistically, however, we must plan on extending this ‘ground truth’ information to cover the entire lunar surface by remote means. In fact, remote sensing techniques will be employed prior to much of the detailed lunar surface exploration in order to define areas of maximum interest. The mid-infrared region of the spectrum is a wavelength region which possesses a high potential usefulness for remote sensing, because the molecular vibration spectra in this region are directly interpretable in terms of molecular composition. It is the purpose of this paper to examine this potential, review the theoretical justification for use of this wavelength region, describe laboratory studies of possible lunar surface materials, and present the data so far obtained from the moon itself.