United States. National Aeronautics and Space Administration

“ So it is that every student of history recognizes the importance of the Renaissance, an extraordinary time when man looked outward, reaching beyond the traditions of the past to study his place in the natural world. The results were apparent in art, architecture, and literature, in new philosophic and governmental systems, and in the staggering scientific revolution exemplified by Galileo’s first examination of the heavens with a telescope, and in his stubborn support of the heretical assertion that the Earth was not the center of the solar system. ”

“ 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. ”

“ The spacecraft was below the ring plane during most of the 3-hour observation period and was much closer to the planet at the end of the period (right of image) than at the start (left of image) . Thus, the images are quite distorted. The small-scale pattern is instrument noise. In the left image, the warm infrared radiation from the planet is seen through Cassini’s Division between the A- and B-rings. The brightness level in the right image implies that Saturn emits heat at a rate that is 2.5 times the rate that it absorbs energy from the sun. ”

“ The United States has always been a nation that moves forward, pushing back the frontiers of the West, pushing back the frontiers of social and economic development, and now pushing back the frontiers of space. ”

“ Pioneer Saturn has already greatly expanded our knowledge of Saturn, its rings and moons. We now know that Saturn, in many ways, represents an intermediate case between Jupiter, the largest planet in the solar system, and Earth. The composition of Saturn’s interior is essentially the same as Jupiter’s, differing only in the size and extent of the various internal layers. Measurements for Saturn are consistent with a central core of molten heavy elements (probably mostly iron) which is the approximate size of the entire Earth, but about three times more massive. ”

“ The impact of a picture of Earth from deep space, a luminously blue globe surrounded by darkness, has probably been more persuasive than lengthy treatises describing the complex ways in which our system of rocks, plants, animals, water, and air is interrelated. On a more practical level, the historian will point to the new understanding of our terrestrial environment. The composition and structure of other planetary atmospheres—on Venus, Mars, and Jupiter—provide important clues to what may happen in our own atmosphere, especially if we disrupt the chemical composition. ”

“ Transcending even these formidable objectives of space bioscience is an objective shared by all life sciences, the discovery of nature's scheme for coding the messages contained in biological molecules. Extraterrestrial biology seeks to find not only evidence of life now present, but the vestigial chemicals of its previous existence. The ways and means have already been made available to study molecules on whose long, recorded messages is written the autobiography of evolution—the history of living organisms extending back to the beginnings of life. ”

“ In slightly over two decades, man has ingeniously explored five distant planets—and two dozen moons. We have seen their weather and surfaces, landed on some, probed the atmospheres of others, and listened to their radio noises.
Under the planetary exploration program of the National Aeronautics and Space Administration, the Voyager Mission, begun in 1972, was designed to explore Jupiter, Saturn, their satellites, rings, magnetic fields, and interplanetary space. Two automated, reprogrammable spacecraft, Voyagers 1 and 2, were launched in late summer of 1977. Their goals: the outer planets. ”

“ Pioneer Saturn image of Saturn and its rings from a distance of 5,500,000 km (August 26, 1979, 6 days before closest approach) . Resolution of features is beginning to be approximately equal to that of Earth-based pictures. Belts on the planet are becoming more distinct, and considerable structure can be seen in the rings. The small blue spot at the bottom of the planet is due to incomplete data and will be corrected by further processing. A notch appears at the top left of the planet, which may be a data transmission problem or the shadow of one of Saturn’s moons. ”

“ SIGNIFICANCE TO SCIENCE One of the most critical research areas of the space program is bioscience. Of both practical and philosophical significance in exploring the origins of life and the possibilities of life on other planets, bioscience also promises much in medical aspects. Space offers biologists completely new environmental factors, such as the effects of zero gravity and of removal from Earth's rotation. ”

“ In only twelve hours, Saturn’s satellites grew from names in ancient mythology into dazzling worlds with personae of their own. As Voyager 1 sailed through the Saturn system, it returned photographs of Mimas, Enceladus, Tethys, Dione, and Rhea—all part of a class of intermediate-sized icy bodies heretofore unstudied by planetary spacecraft. ”

“ The goals of the Bioscience Program are: (1) to determine if extraterrestrial life exists anywhere in the solar system and to study its origin, nature, and level of development, if it is present; (2) to determine the effects of space and planetary environments on Earth organisms, including man; (3) to conduct biological research to develop life support and protective measures for extended manned space flight; and (4) to develop fundamental theories in biology relative to origin, development, and relationship to environment. ”

“ Looking beyond matters of technology and the environment, the historian may cite the latter part of the twentieth century as a time of explosive exploration, comparable to the 15th and 16th century exploration of the Earth’s oceans and the distant lands that bounded them. In a sense, exploration—whether it is physical or intellectual—provides its own rewards. ”

“ As Voyager 1 approached Saturn, a series of dark and light cloud bands (belts and zones) became apparent in the planet’s northern hemisphere through a high altitude atmospheric haze. The planet’s shadow obscures the rings behind and immediately to the east of the disk. In addition, the shadow of the rings on the planet’s disk can be seen just north of the rings themselves as they cross in front of the planet. Six of Saturn’s 15 known satellites are visible. Saturn’s largest moon, Titan (considerably larger than Earth’s moon) , is clearly visible in the upper left corner. ”

“ At the point of closest approach, it attained a speed of 114,100 km/h (71,900 mi/h) and came within 21,400 km of the planet’s cloud tops. While it was approaching, encountering, and leaving Saturn, the spacecraft took the first closeup pictures of the planet, showing 6 20 to 30 times more detail than the best pictures taken from Earth, and made the first close measurements of its rings and several of its moons, including the largest moon, the planet-sized Titan. Titan, along with Mars, has been considered by many scientists to be the most likely place to find life in the solar system. ”

“ Production of 1 liter of oxygen results in the production of 1 gram dry weight of algae. Although a small amount of CO is produced by some algae, it can probably be removed by catalytic oxidation. Other problems include mutation and genetic drift of the algae and the necessity for maintaining bacteria-free cultures. There are also difficulties in maintaining a sterile culture if urine is to be used as a nitrogen source. While there is a potential for using algae as food, more research is required before it can be determined what quantity and methods of processing can be used. ”

“ It appears that organisms from Earth might survive in large numbers when introduced to Martian environment. Whether these organisms will be capable of growth and explosive contamination of the planet in a biological sense or not is highly questionable. The likelihood of an organism from Earth finding ideal conditions for growth on Mars seems extremely low. However, the likelihood of an organism from Earth serving as a contaminant for any life-detection device flown to Mars for the purpose of searching out carbon-based life is considerably higher. ”

“ The broad national space goals initially charted by NASA have gone beyond space flight in near-Earth orbit to lunar and interplanetary exploration by man and machine. For such missions, more intensive and comprehensive research in the life sciences is needed. Before manned voyages for extended periods into deep space will be possible, solutions must be found for problems such as the development of bioregenerative life-support systems, communication with nonhuman species, and the development of new methods for transferring knowledge to the human brain. ”

“ In many parts of the world, people live on a monotonous diet consisting of only a few types of food with no apparent ill effects, provided their nutritional requirements are satisfied. Experimental evidence from many sources (e.g., the Army Medical Research and Nutrition Laboratory) shows that individuals can be kept on a single disagreeable formula diet for as long as 60 to 90 days without harm. Since highly motivated individuals are chosen for space flights, it is unlikely that they would object to the monotony of a formula diet and would probably prefer its simplicity. ”

“ BIOLOGICAL EFFECTS OF WEIGHTLESSNESS AND ZERO GRAVITY High priority has been given to studies of weightlessness. Gravity is one of the most fundamental forces that acts on living organisms, and all life on Earth except the smallest appears to be oriented with respect to gravity, although certain organisms are more responsive to it than others. The gravity force on Earth is 1 g, but this force may be experimentally varied from zero g, or weightlessness, to many thousands of g's. ”

“ The extreme ranges of physical and chemical environmental factors for growth, reproduction, and survival for Earth micro-organisms are phenomenally large.
Life is ubiquitous on Earth and is found in almost every possible environment, including the most severe habitats, from the bottom of the ocean to the highest mountain tops and from cold Arctic habitats to hot springs, as well as in volcanic craters, deep wells, salt flats, and mountain snowfields. Earth life has become adapted to, and has invaded, nearly every habitat, no matter how severe. ”

“ These include the quest for the origin of life, the explanation of life and life processes, the elucidation of the environment's role in establishing and maintaining normal organization in living organisms, the possibility of extraterrestrial life on other planets—the concern of exobiology. The greatest promise for their solution lies in advances in biological theory rather than other avenues of research; therefore, it is fortunate that the need to solve them has come at a time when developments in experimental biology are at a high level. ”

“ The Panel on Radiation Biology, while recognizing the need for radiobiological studies of an applied nature with reference to manned flight programs, stated that it would be shortsighted for the United States to confine its efforts to the solution of immediate problems since, in the long run, successful exploration of space will be aided by the contributions of basic research. Both the immediate biological research program and the continuing program for basic studies should be built upon the large body of existing knowledge of radiation effects. ”

“ The Earth's present atmosphere consists of nitrogen and oxygen in addition to relatively small amounts of other gases; most of the oxygen is of biological origin. Some of the atmospheric gases, in spite of their low amounts, are crucial for life. The ultraviolet-absorbing ozone in the upper atmosphere and carbon dioxide are examples of such gases.
Significant in the search for extraterrestrial life are the data (e.g., planet's temperature) transmitted by Mariner II, which was launched from Cape Canaveral on August 27, 1962, and flew past Venus on December 14, 1962. ”

“ Life on Earth is usually considered to be relatively limited in its ability to grow, reproduce, or survive in extreme environmental conditions. While many common plants and animals (including man) are quite sensitive to, or incapable of, surviving severe chemical and physical changes or extremes of environment, a large number of micro-organisms are highly adapted and flourish in environments usually considered lethal. Certain chemoautotrophic bacteria require high concentrations of ammonia, methane, or other chemicals to grow. Anaerobic bacteria grow only in the absence of oxygen. ”