Planetary science, also referred to as Earth science or geoscience, is the study of non-stellar celestial bodies, such as planets, planetoids, asteroids and moons.
In 2266, the USS Enterprise monitored the disintegration of Psi 2000. During the monitoring, the Earth science department required the Enterprise to get into "a critically tight orbit," in order to get the closest possible measurement of the planet's breakup. (TOS: "The Naked Time")
Commander D. Wise served in the planetary science division aboard the USS Enterprise-A in 2293. (Star Trek VI: The Undiscovered Country)