He is principal investigator on the EUV (extreme ultraviolet) and X-Ray Irradiance Sensors (EXIS) on the NOAA GOES-R satellite series, instrument and project scientist on the EUV Variability Experiment (EVE) on the NASA Solar Dynamics Observatory (SDO), instrument lead on the EUV monitor on the NASA MAVEN mission to Mars, and instrument scientist on the Solar EUV Experiment (SEE) on the NASA TIMED mission. His research interests are in the areas of solar irradiance variability and its effects on the upper atmospheres of the Earth and other planets.