Streaks and flashes of light perceived by astronauts with eyes open or closed, first widely reported on Apollo missions, now well documented as high-energy cosmic rays passing through the eye and striking the retina. A worked example of an anomaly report resolving into physics within a few missions.
PURSUE Release 04 records NASA-UAP-D026 to D029 carry the Apollo 14 and Apollo 17 post-mission debriefings on the phenomenon; Release 02’s astronaut audio (NASA-UAP-D008 to D014) covers the related Mercury “fireflies” and Apollo 12 flashes. Cosmic-ray exposure remains a live design concern for deep-space crewed flight.