Summary
This excerpt from the January 8, 1973 Apollo 17 Crew Debriefing for Science features co-investigator Dick Henry discussing unexpected results from the mission's ultraviolet experiment. He explains that the observed spectrum resembled that of hot stars even though none were in the field of view, offering reflection off interstellar dust as the most conservative interpretation while noting possible extragalactic radiation.
Detail
Apollo 17 was the ninth crewed U.S. mission to the Moon and the sixth to land astronauts on the lunar surface. This document is an excerpt from the Apollo 17 Crew Debriefing for Science, dated January 8, 1973, in which Dick Henry, co-investigator on the mission's ultraviolet experiment, discusses results he had not anticipated.
Henry notes that an unexpected X-ray background had been observed across the sky, and that in the ultraviolet the team examined many points at high galactic latitudes. The spectrum they recorded rose above the instrument's dark count and resembled that of hot stars, even though no hot stars lay within the field of view. He offers as the most conservative interpretation that the light came from hot stars in the galactic plane reflecting off interstellar dust, while acknowledging certain features of the spectrum did not fit that theory and that extragalactic radiation remained possible pending detailed computer study.
The document was released through the PURSUE declassification.
