NASA-UAP-D029, Apollo 17 Crew Medical Debriefing (Continued), 1972

Official Conclusion

Light flashes observed by crew attributed to high-energy cosmic rays striking the retina — a biological effect, not an anomalous phenomenon.

Official Description

This file contains segment 2 of 2 of the Apollo 17 post-mission medical debriefing at the Manned Spacecraft Center (now Johnson Space Center), Houston, Texas. In this continued segment, crew members and debriefers further discuss the “light flash phenomena,” a then novel, now well-documented biological effect where high-energy cosmic rays pass through the eye and strike the retina, causing the perception of light streaks or flashes. Two of the three crew members reported observing these flashes at various points during the mission, including in lunar orbit and while on the lunar surface.

Key Findings

• →Two of the three Apollo 17 crew members reported experiencing light flash phenomena during the mission, both in lunar orbit and on the lunar surface.
• →The light flash phenomena is attributed to high-energy cosmic rays passing through the eye and striking the retina, causing perception of light streaks or flashes.
• →The debriefing was conducted at the Manned Spacecraft Center (now Johnson Space Center) in Houston, Texas, following the Apollo 17 mission.
• →The phenomena was described as 'novel' at the time of the 1972 debriefing but is now a well-documented biological effect in spaceflight medicine.
• →This segment is a continuation of a two-part medical debriefing, indicating the topic warranted extended discussion during post-mission review.

Extracted Entities