Biological research is fundamental to the problem of successfully protecting and sustaining man in the peculiar and hostile space environment. Understanding human requirements and variations in their response to various environmental factors offers value in medical research for human survival and comfort. The many technological discoveries and advancements in electronic and engineering equipment greatly enhance medical diagnosis, treatment of disease, and the extension of human life. The life sciences, biology and medicine, are fundamental to the success of manned exploration of space, which marks a unique and significant development in the long history of man’s conquest of new frontiers. Those who pioneered other frontiers on land and sea and in the air were not forced to await biological and medical research. Even the pioneers of aerial flight began their efforts without first seeking biomedical data. The search for such data followed flight experience and, indeed, was made only after problems arose. Project Mercury, NASA’s first program for manned space flight, stimulated immediate and extensive studies in the life sciences to sustain man in space. Before a vehicle could be designed to carry an astronaut into space, anticipated biomedical problems associated with space flight were studied. Life-support systems were designed to offer adequate protection from environmental stresses peculiar to space, such as zero gravity, removal from Earth’s rotation, and high-energy cosmic radiation. These life-support systems used knowledge already gained from research for manned space flight by the U.S. Air Force. Our entry into space has put us at the threshold of fundamental and far-reaching discoveries in the biological realm which have profound implications for other areas of human thought and endeavor. As man goes farther into space, the hazards increase; but past accomplishments indicate that the road ahead holds more promise than peril and that the vistas of knowledge that may be foreseen are as vast as space itself. Almost everything which now can be said about the effects of extraterrestrial environments and about life on the Moon or the planets lies in the realm of pure speculation. There is one prediction, however, that can be made with considerable certainty by reason of historical precedent—the opportunity to investigate a totally new area, such as is offered by space exploration, is certain to produce a burst of scientific interest as soon as the path is charted by a few pioneers. Over the next few decades a progressively larger proportion of biological interest will turn to space. We may well expect that the discoveries made here will revolutionize some of our concepts of biology. It should be fully realized that the accumulation and dissemination of biological and other scientific information is not only of great value to science and humanity but is of tremendous import to the prestige of the Nation.