A method for remote analysis of materials embedded in a frozen surface, such as in the icy surface of a planetary body. A laser on board a spacecraft irradiates the frozen surface and thereby releases materials in a gas cloud, by a process of desorption. The laser wavelength is selected to maximize the release of substances by the desorption process, which does not fragment materials into their elemental components. An infrared (IR) spectrometer on the spacecraft detects thermal emissions from the gas cloud against a background provided by the frozen surface, and can readily identify a variety of organic, inorganic and biological materials from their thermal spectra.