The effects of cosmic particle radiation on pocket mice aboard Apollo XVII: I. Project BIOCORE (M212), a biological cosmic ray experiment: procedures, summary, and conclusions.

The primary objective of the experiment was to determine whether a specific portion of the high Z-high energy (HZE)* galactic cosmic ray particle spectrum, especially particles with Z greater than or equal to 6, can produce microscopically visible injury of brain and eye tissues. Pocket mice (Perognathus longimembris), obtained from the California desert, were selected as the biological target. Five of these mice were flown on Apollo XVII. Not only the brain and eyes but also many other tissues of these animals were studied for evidence of cosmic ray particle damage. The lack of prior experimental evidence as to the character of the potential injury induced by HZE particles required reliance on the physical characteristics of particle radiation in ascertaining the probable nature of the injruy. These characteristics and the key aspects of the experiment are summarized in this paper. Subsequent articles in this special supplement give details of the biological, engineering, and dosimetric aspects of BIOCORE together with the results.

The effects of cosmic particle radiation on pocket mice aboard Apollo XVII: VI. launch, flight, and recovery.

The final phase to fly five pocket mice in the Apollo XVII command module was carried out at the NASA Kennedy Space Center. Upon completion of the 13-d space flight, the package was removed from the spacecraft and, after having been purged with an oxygen-helium gas mixture, was flown to American Samo. Four of the five mice were recovered alive from the package. Analysis of the mouse that died during the flight revealed several factors that could have contributed to its death, the chief of which was massive hemorrhage in its middle ear cavities.

The effects of cosmic particle radiation on pocket mice aboard Apollo XVII: X. Results of ear examination.

In the five pocket mice flown on Apollo XVII, no evidence was found that the inner ear had been damaged, though poor fixation precluded detailed study. On the other hand, the middle ear cavity was involved in all the mice, hemorrhage having occurrred in response to excursions in pressure within the canister that housed the mice during their flight. The same occurred in flight control mice which had been subjected to pressure excursions of much the same magnitude. A greater degree of exudation into air cells and greater leukotaxis were noted in the flight animals than in the control animals. There was no increase in leukocyte population along the paths of the 23 cosmic ray particles registered in the subscalp dosimeters that traversed the middle ear cavities of the flight mice. The increased exudation and the greater response by leukocytes in the flight mice may have been causally related to the lesions found in their olfactory mucosa but there were no data in support of this possibility.

The effects of cosmic particle radiation on pocket mice aboard Apollo XVII: IX Results of examination of the nasal mucosa.

The olfactory epithelium, but not the nasal respiratory epithelium, of the four pocket mice (Perognathus longimembris) that survived their flight on Apollo XVII showed both diffuse alterations and numerous disseminated focal lesions. The olfactory mucosa of the mouse that died during flight was also affected, but to a minor degree insofar as could be determined. All this was in contrast to the normal appearance of the olfactory mucosa of the numerous control animals. A number of possible causes were considered: systemic or regional infection; inhaled particulate material (seed dust); by-products from the KO2 bed in aerosol or particulate form; gas contaminants originating in the flight package; volatile substances from the dead mouse; weightlessness; and cosmic ray particle radiation. Where feasible, studies were conducted in an effort to rule in or rule out some of these potentially causative factors. No definitive conclusions were reached as to the cause of the lesions in the flight mice.

The effects of cosmic particle radiation on pocket mice aboard Apollo XVII: IV. engineering aspects of the experiment and results of animal tests.

A closed passive system independent of support from the spacecraft or its crew was developed to house five pocket mice for their flight on Apollo XVII. The reaction of potassium superoxide with carbon dioxide and water vapor to produce oxygen provided a habitable atmosphere within the experiment package. The performance of the system and the ability of the mice to survive the key preflight tests gave reasonable assurance that to mice would also withstand the Apollo flight.