A vital subsystem for NASA's Nancy Grace Roman Space Telescope was recently delivered to Ball Aerospace in Boulder, Colorado, and installed in the spacecraft's Wide Field Instrument (WFI). Called the Simplified Relative Calibration System (sRCS), this component will allow astronomers to measure the total light output of cosmic objects like galaxies and supernovae with extreme accuracy. When Roman launches by May 2027, scientists will use this data to unravel the secrets of dark energy and dark matter, discover exoplanets, and explore many topics in infrared astrophysics.