Studies of Astronauts During Spaceflight

Abstract

As already related, my application to NASA to make measurements of common root function in astronauts in space was funded, and the first funds were available on the day I started at UCSD. However it took some time to prepare the experiments for this unique environment. The first measurements were made in 1977 when we looked at the effects of short periods of weightlessness obtained in aircraft during parabolic flights. These occur when an aircraft first climbs, and then the pilot puts the nose down and there is a period of as much as 27 s of zero gravity. We made these measurements at the Ames Research Center and showed dramatic changes in the distribution of ventilation and blood flow as would be expected from the known of effects of gravity on the lung. However the main experiments were planned for SpaceLab which was carried upt by the Shuttle. Preparations for these experiments were protracted because of their complexity. Also the program was set back by 2 years because of the Challenger accident in 1986. However eventually we had experiments on SpaceLabs SLS 1, SLS 2, LMS and Neurolab. Kim Prisk was responsible for superintending the actual experiments. A remarkable feature of the experiments was that most of the data was available in real time and we could access this at the Johnson space Center near Houston. Large amounts of data were obtained in an environment where none were available before, and these were reported in many publications. As expected the function of the lung was altered in microgravity but we were relieved to find that gas exchange could still be easily accomplished. When the International Space Station became available, measurements that were made there showed that even after 6 months in space, the astronauts rapidly the lung function of the astronauts rapidly returned to normal after a few days. The upshot was that as far as we can tell, changes in pulmonary function will not be a serious problem during long-term spaceflight, for example in a 3-year mission to Mars. However such a mission has other serious dangers such as harmful radiation.