Michelsen was an undergraduate at
Dartmouth College. Initially majoring in English, she became interested in
environmental science before graduating in 1984 with high honors in chemistry; she also earned the college's Chandler T. White 1916 Research Prize. She went to
Stanford University for graduate study in chemistry, also working as a student researcher at the
IBM Almaden Research Center, and supported in part by the Nellie Yeoh Whetten Award of the
American Vacuum Society. She completed her Ph.D. in 1993. Her doctorate involved surface chemistry in electronics manufacturing, but looking for a change of pace, she switched her research interests afterwards to
atmospheric chemistry. After postdoctoral research at
Harvard University, Michelsen became a staff scientist for Atmospheric and Environmental Research, Inc. in 1997, and a member of the technical staff in the
Sandia National Laboratories Combustion Research Facility in 1999. She returned to academia in 2019, as an associate professor of mechanical engineering at the University of Colorado Boulder. In 2020 she added an affiliation with the university's program in environmental engineering. ==Recognition==