Patent ID: 7067812

Claim:
A method for determining the presence of a predetermined surface material on a planetary body, the method comprising the steps of, generating a laser pulse at a first wavelength, the first wavelength being at an absorption band peak of an absorption band of the predetermined surface material, the absorption band absorbing the first wavelength and reradiating the first wavelength as selective reflection first returns, illuminating the planetary body with the first wavelength, detecting first returns from the planetary body, the first returns being the selective reflection first returns of the first wavelength, generating a laser pulse at a second wavelength, the second wavelength being outside the absorption band of the predetermined surface material, the absorption band not absorbing the second wavelength and not reradiating the second wavelength, illuminating the planetary body with the second wavelength, and detecting second returns from the planetary body, the second returns being returns of the second wavelength, and determining the presence of the material on the surface of the planetary body by comparing the first and second returns to each other, the first returns being greater than the second returns as the first returns are reradiated by the predetermined surface material and the second returns are not reradiated by the predetermined surface material.