Seven hundred twenty beetle pupae between 19 and 27 hours of age were orbited, half in the presence of 85Sr and half shielded from it. Two-thirds of each pupae group had received a preflight radiation dose (1,350 r) of 180 keV x-rays. Identical ground controls were maintained. It was found that, by choosing an appropriate temperature, the rate of development of the organism could be slowed down or speeded up in such a manner that the organisms could be maintained in pupal stage, so most of the wing development would take place after reaching weightlessness. Upon return, the pupal period, wing abnormalities, and genetic damage were determined by mating experimental beetles with controls. In addition to the Biosatellite controls, a study was conducted to determine if variations could be found from in a different control capsule, as well as a postflight vibration control.

Results:

Pupal period, wing abnormalities, and dominant lethality were significantly increased. "Split" mutation increased from ground values of 30% to 45% for flight. Numerically, the vibrated irradiated groups had fewer wing abnormalities than did the appropriate controls, whereas the flight-irradiated sample had more abnormalities than the ground-controls, suggesting that vibration was not the cause of the increased wing abnormalities in flight samples. No differences were detected as a result of the capsule comparison control. Some factor in space flight, probably weightlessness, either facilitated the development of radiation- induced chromosome breaks and/or DNA damage in the meiotic cells (oocytes), or hindered the normal correction of such errors. Another possible explanation is a temperature drop of the flight samples that occurred between separation and retrieval of the flight capsule.