Mars

7 Pages 1730 Words

's, and the polar caps proved to be almost entirely frozen CO2. The first global views of Mars, returned by the Mariner 9 orbiter in 1972, revealed that the planet was far more complex than the earlier flyby missions had shown, with huge volcanoes, an enormous canyon system, and evidence of running water at some point in the past. But the wave of darkening was shown to be the result of seasonal redistribution of windblown dust on the surface, the atmosphere's composition and density were confirmed, and most of the evidence for an Earthlike Mars was swept away.

But despite all these blows, the possibility of organisms on the surface could not yet be ruled out. For this reason, in 1976 the Viking landers carried a sophisticated instrument to look for possible life forms on the martian surface.


The Viking Biology Experiment
The Viking biology experiment weighed 15.5 kg (34 lbs) and consisted of three subsystems: the Pyrolytic Release experiment (PR), the Labeled Release experiment (LR), and the Gas Exchange experiment (GEX).

Viking Biology Experiment

In addition, independent of the biology experiments, Viking carried a Gas Chromatograph/Mass Spectrometer (GCMS) that could measure the composition and abundance of organic compounds in the martian soil. (It should be noted that organic is a chemical term simply meaning "carbon-containing", and does not require the presence...