NASA-UAP-D015: Astronaut Scientific Debriefings, 1962-1963

Source file: NASA-UAP-D015_Astronaut-Scientific-Debriefings_1962-1963.pdf Originating agency: National Aeronautics and Space Administration Classification: CONFIDENTIAL (Declassified) Date range: 1962-1963 Page count: 127 PURSUE Release: 3

Summary

This collection brings together NASA internal memoranda, scientific correspondence, and debriefing transcripts generated in the immediate aftermath of the first American orbital spaceflights. Its focus is a cluster of anomalous visual phenomena that startled the early Mercury astronauts: thousands of luminous particles appearing outside the spacecraft at orbital sunrise, an unexplained airglow band visible at the horizon, and the unexpected brightness of atmospheric and meteoric phenomena seen from orbit.

The most significant item is a February 21, 1962 memorandum from Maurice Dubin, Head of the Aeronomy Program at NASA's Office of Space Sciences, requesting an urgent interview with Colonel Glenn to document his observations of luminous particles and the upper limb of the atmosphere during MA-6. The file then traces the scientific effort to explain what Glenn, and later Scott Carpenter on MA-7, had seen. It also includes a June 1963 scientific debriefing of L. Gordon Cooper regarding a flashing-beacon experiment on MA-9.

Research Article

The Glenn effect: luminous particles at sunrise

During the MA-6 mission on February 20, 1962, John Glenn reported seeing thousands of bright luminous particles surrounding the Friendship 7 capsule at orbital sunrise. The phenomenon attracted immediate scientific attention. A memorandum dated February 21, 1962, signed by Maurice Dubin (Head, Aeronomy Program, Geophysics and Astronomy Programs, Office of Space Sciences), urged that Glenn be interviewed "as soon as possible" to document "the great number of luminous particles apparently travelling with the spacecraft at Friendship-7 sunrise." The memo posed the essential questions: Were the particles actually travelling with the spacecraft, did the condition persist on subsequent orbits, and how did their brightness compare with known astronomical references?

Scott Carpenter on MA-7 (May 24, 1962) independently observed and photographed the same phenomenon -- described as "white objects resembling snowflakes" -- on all three of his orbits. Carpenter also performed the decisive experiment: "Shortly before reentry, just at sunrise, Carpenter performed the decisive experiment of hitting the capsule walls with his hand. The blows promptly resulted in the liberation of large numbers of particles." This established that at least some of the particles emanated from the spacecraft itself.

The scientific analysis, contained in a draft note on scientific observations in the file, concluded that the most probable source was snow formed by condensation of steam from the life-support system, expelled from the capsule at sunrise as temperatures rose. The particles were estimated at between 1 mm and 1 cm in size, with brightness consistent with centimeter-scale snowflakes illuminated by direct sunlight. An alternative source -- small particles of dust, insulation waste, and other debris suspended in the zero-g interior -- was also considered. The analysis explicitly ruled out any extraterrestrial origin.

The airglow layer and atmospheric limb

The file also addresses a second observation from the early Mercury flights: a luminous band visible at the horizon. Lt. Commander Carpenter conducted a systematic study of this layer during MA-7 using an airglow filter supplied by Lawrence Dunkelman of Goddard Space Flight Center. The filter was centered at 5577 Angstroms, the wavelength of the strongest radiation of the night airglow. "The filter cut out all other light, but passed the light of the luminous band, which is thus identified as the 5577 layer." Carpenter measured the layer's brightness as approximately 3 lumens per square meter per steradian -- about 50 times brighter than a white surface illuminated by moonlight -- and determined that the densest part of the layer lay at approximately 89 kilometers altitude, consistent with independent rocket measurements.

Capt. Virgil I. Grissom had also reported a "grayish band at the top of the blue sky layer" during the second U.S. manned suborbital spaceflight. The analysis noted that this was likely the daytime airglow.

Cooper's flashing-light experiment: MA-9, June 1963

The file includes a transcript of a scientific debriefing held on June 1, 1963, attended by NASA scientists John McKee, Bill Armstrong, and Alan Shepard, at which L. Gordon Cooper described his attempt to visually acquire a ground-deployed flashing beacon during the MA-9 mission. The discussion is notable for its candor about the difficulty of the experiment and for Cooper's description of an unexpected light source during the second night pass: "As I watched it was getting higher in my line of sight to the earth... it was solid light. My first thought on it was that it looked just like the missiles that I have seen launched at night from Cape Canaveral... very very bright, and solid and seemed to be coming up."

Cooper ultimately concluded this was sunlight reflecting off his retro pack, not the beacon. The file records that the beacon had functioned correctly on the ground, and that Armstrong told Cooper it would have been "impossible for this light to have been steady for you. It is necessary to fully charge the condenser and then get a quick discharge." Cooper's failure to see the flashing beacon on the first night pass remained unresolved.

Significance

These documents are significant for PURSUE because they represent the beginning of a formal NASA scientific effort to investigate and explain what astronauts were seeing in orbit. The Glenn effect became a recurring feature of early American spaceflight -- it recurs in Gemini debriefings throughout this batch -- and the 1962-1963 scientific effort to characterize it established a methodological baseline. The conclusion that spacecraft-associated particles were responsible was scientifically sound, though the phenomenon continued to generate discussion in later missions.

Key People

Notable Quotes

"Two (2) interesting observations were reported in the Press, as described by Colonel Glenn during the MA-6 flight. It is of vital interest to obtain a more detailed description of these observations in order that the accuracy and the details of what was observed may be properly recorded for scientific evaluation." -- Dubin memorandum, February 21, 1962, p. 34

"The blows promptly resulted in the liberation of large numbers of particles. It is thus clear that at least those particles observed in the MA-6 flight emanated from the capsule." -- Draft of note on scientific observations, p. 60

"It is considered most likely that the particles of the Glenn effect are snowflakes formed in the capsule, between the cabin bulkhead and the heat shield by the steam exhaust from the life-support system." -- p. 62

"My first thought on it was that it looked just like the missiles that I have seen launched at night from Cape Canaveral; when you're flying at night at a high altitude and see them launched. It didn't have the same glow but it was very very bright, and solid and seemed to be coming up." -- Cooper, scientific debriefing, June 1, 1963, p. 67