The California Institute of Technology (Caltech) has an enlightened perspective on science. The institute enrolls about 2,100 students and offers about two dozen majors across six academic divisions focused on biology, chemistry, engineering, geology, humanities, and physics. Caltech has a very low student-teacher ratio of 3:1. The school receives about half of its operating revenue through research grants, primarily from government agencies. Caltech operates the Jet Propulsion Laboratory (JPL), which supervises robotic Mars exploration programs and other interplanetary missions, under contract to NASA. The school was founded in 1891.