Optical technician, Timothy Madison, uses a theodolite to perform optical measurements on the Ocean Color Instrument (OCI). As he collects data and measures angles on OCI, he is able to determine if the newly integrated flight hardware is in the correct position. OCI is a highly advanced optical spectrometer that will be used to measure properties of light over portions of the electromagnetic spectrum. It will enable continuous measurement of light at finer wavelength resolution than previous NASA satellite sensors, extending key system ocean color data records for climate studies. OCI is PACE's (Plankton, Aerosol, Cloud, ocean Ecosystem) primary sensor built at Goddard Space Flight Center in Greenbelt, MD.