Our preliminary understandings of a planet's composition, surface environment, and evolutionary history are based on remote sensing of the planet's surface. Motivated by the fundamental questions on how a planet evolves and becomes habitable, numerous planetary missions have been designed and carried out to characterize solar system planets with diverse geologic processes. In this lecture, I would first provide an overview of the physical and chemical processes that shape the surfaces of solar system solid planets and introduce the remote sensing methods. Then, I will take Mars as an example and discuss how the geologic and climate history of Mars has been unravelled and why Mars may have experienced such a diverging history from Earth. In closing, I will highlight the emerging new approaches and discuss the outlook of Mars exploration in the context of Mars sample return.
