In 1976, two Viking spacecraft were set on their course to Mars, each outfitted with an orbiter to snap photographs of the surface and with a lander that conducted scientific experiments on soil samples. Neither of the probes detected evidence of life on Mars, but examining the benefits of the missions requires looking beyond--or below--these results.
The Martian surface is self-sterilizing. The combination of solar ultra-violet light and the dryness of the soil prevents the formation of living organisms in the Martian soil. Could life be living underneath the surface? Maybe creatures had established a habitat far below the harsh surface. Viking was not designed to test below the surface soil.
Photo. A Viking Orbiter photo of an ancient, dried-up riverbed. Courtesy of NASA, JPL.
The Viking missions were designed to last up to ninety days after landing on the surface of Mars, but each Orbiter and Lander far exceeded its expected life. Some 4,500 photographs from the Landers provided the most complete view of Mars to date. Orbiter 1 was active for more than four years! Orbiter images, 52,000 of them, showed volcanoes, lava plains, immense canyons, cratered areas, wind-formed features, and evidence of surface water.
Photo. Rising 15 mile high and stretching 300 mile wide, Olympus Mons is an extinct volcano on Mars, the highest mountain and biggest volgano in the solar system. Courtesy of NASA, JPL.
These two missions cost American taxpayers over a billion dollars, but not all of that was shot into space. Most of the money stayed here, to pay the salaries of all the scientists working on the space program; it is worth noting as well that the Vikings included numerous, redundant backup systems--safeguards not unreasonable considering the probes were NASA's first visit to the Martian surface.
The low-cost Mars Pathfinder mission launched in December 1996 with a flawless landing and astounding results the next July invites cost comparison with the Viking missions: the Vikings would have cost $3 billion in 1997 dollars while the Pathfinder cost just $250 million. Nonetheless, it was, interestingly enough, images from the Viking Orbiters that allowed Jet Propulsion Laboratory mission planners to pinpoint Pathfinder's landing site.
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