NASA Arcstone satellite and spectrometer begin active lunar calibration missionby Clarence OxfordLos Angeles CA (SPX) Sep 17, 2025Commissioning of NASA's Arcstone satellite and spectrometer has been completed, marking the transition to full scientific operations. Launched July 23 on a SpaceX Transporter-14 rideshare mission from Vandenberg Space Force Base in California, the satellite's bus and instrument underwent initial checkouts before activation. On August 13, Arcstone began recording validated solar and lunar spectral measurements, the first dedicated effort to refine the precision of lunar reflectance calibration from orbit. By analyzing sunlight reflected from the Moon, Arcstone will establish a universal reference that can fine-tune other spacecraft instruments while on-orbit. NASA describes this approach as a way to improve the accuracy of Earth-observing data while lowering mission complexity by reducing the need for onboard calibration systems.