Planetary Spectroscopy

Planetary spectroscopy uses physical methods to study the chemical properties of the geological materials on the planetary bodies in our solar system. This article will present twelve types of spectroscopy frequently used in planetary explorations. Their energy (or wavelength) varies from γ-ray (keV) to far-infrared (μm), which involves the transitions of nuclei, atoms, ions, and molecules in planetary materials. The article will cover the basic concept of the transition for each of the twelve types of spectroscopy, along with their legendary science discoveries made during the past planetary exploration missions by the international planetary science and engineering community. The broad application of spectroscopy in planetary exploration is built upon the fact that only limited extraterrestrial materials were collected (meteorites, cosmic dust, and the returned samples by missions) that enabled the detailed investigations of their properties in laboratories, while spectroscopic measurements can be made on the objects of our solar system remotely and robotically, such as during the flyby, orbiting, lander, and rover missions. In this sense, the knowledge obtained by planetary spectroscopy has contributed to a major portion of planetary sciences. In the coming era of space explorations, more powerful spacecraft will be sent out by mankind, go to deep space, and explore exotic places. Generations of new planetary science payloads, including planetary spectrometers, will be created and will fly. New sciences will be revealed.