Uniformed Services University


The spirit for continued investigation of the potential for life on Mars is now revived in part by the early eye-opening results from NASA Opportunity and Spirit Mars rover missions. The tell-tale clues that Meridiani Planum (12) was water soaked at one time have opened the floodgates of discussion in how best to study Mars in ever-greater detail, as well as sharpen our search for past and even present life [Richmond et al., 1999]. That provocation has been supported in the past by the persistent logic of life allowable signatures from the Viking Lander experiments, by the growing awareness of how remarkably adaptable life is on Earth to a variety of extreme environments that feasibly mimic past and/or present habitats available at various locations throughout our solar system, and by the growing acceptance of the multifactorial merger of knowledge regarding the creation and evolution of the Inner Planets. Some of the more provocative factors regarding the latter are: knowledge of early emergence of life on Earth, even during its late stages of accretion up to 4 billion years ago; probable similarities of both Earth and Mars habitats during early geologic times up to 3 billion years ago or less; accumulating evidence supporting cross fertilization of planetary material between Mars and Earth as was initially proposed in the panspermia hypothesis; a growing evidence and acceptance of subsurface aqueous reservoirs on Mars; recent firm estimates of large water ice reservoirs in both polar ice caps on Mars; and recent evidence for young (within approximately the last 300,000 years) substantial martian volcanism that supports a high probability for continuing volcanism.