The biological exploration of Mars is a scientific undertaking of the greatest significance. Its realization will be a major milestone in the history of human achievement. The characterization of life, if present, and study of the evolutionary processes involved and their relationship to the evolution of terrestrial life would have a great scientific and philosophical impact. What is at stake is nothing less than knowledge of our place in nature.
Extended Earth orbital flights with subhuman specimens will be used to determine the effects on Earth organisms of prolonged weightlessness, radiation, and removal from the influence of the Earth's rotation. Such flights of biosatellites and other suitable spacecraft are expected to: (1) establish biological specifications for extending the duration of manned space flight; (2) provide a flexible means of testing unforeseen contingencies, thus providing an effective biological backup for manned missions; (3) yield experimental data more rapidly by virtue of the greater number and expendability of subjects; (4) anticipate possible delayed effects appearing in later life or in subsequent generations, through use of animal subjects with more rapid development and aging; (5) develop and test new physiological instrumentation techniques, surgical preparations, prophylactic techniques, and therapeutic procedures which are not possible on human subjects; and (6) provide a broad background of experience and data which will permit more accurate interpretations of observed effects of space flight on living organisms, including man.
[chapter 2]
Exobiology
The possibility of discovering an independent life form on a planet other than Earth presents an unequaled challenge in the history of scientific search. Therefore, the detection of life within the solar system is a major objective of space research in the foreseeable future.
The scientific data presently available concerning the possible existence of a Martian life form and the chemical constitution of the surface of Mars are disappointingly few. In fact, it is impossible to make a statement about any of the many surface features, other than the polar caps, with any degree of certainty. The observational results have been accounted for by many conflicting hypotheses which can only be resolved by the accumulation of new evidence.
The arguments supporting the existence of Martian life ([ref.1]) are based on the following observations:
- The various colors, including green, exhibited by the dark areas
- The seasonal changes in the visual albedo and polarization of the dark areas
- The ability of the dark areas to regenerate after an extensive "duststorm"
- The presence of absorption bands at 3.3µ-3.7µ, attributed to organic molecules
Conflicting interpretations of the above observations have been advanced. The argument based on the colors is inconclusive, and several workers have suggested that the color is a contrast effect with the bright-reddish continents. The meager quantitative data have been discussed by Öpik ([ref.2]) who has reduced Kozyrev's photometric observations of the very dark area of Syrtis Major to intrinsic reflectivities by allowing for the estimated atmospheric attenuation and reflectivity. Kuiper ([ref.3]) similarly demonstrated the absence of the near-infrared reflection maximum, which is characteristic of most green plants, indicating that chlorophyll was not responsible for the color.
The second and third arguments remain the most cogent. However, serious limitations are imposed on the second if the severity of the Martian climate is considered. Föcas ([ref.4]) has photometrically measured the seasonal changes in the fine structure of the dark areas of Mars and concludes that—