The Viking landers may have missed potential signs of life when they explored Mars in 1976, an international research team asserts.
NASA's two unmanned Viking craft landed on Mars, took pictures, and conducted a variety of experiments. While some of the data suggested biological activity in the Red Planet's soil, the chemical analyses didn't turn up organic compounds, expected to be present if there were life there.
The data became the basis for arguments against current or past life on Mars, says Rafael Navarro-González, a chemist at the National Autonomous University of Mexico in Mexico City.
The Viking landers used a technique called thermal volatilization–gas chromatography–mass spectrometry (TV-GC-MS) to analyze the soil. In that process, an instrument vaporizes a soil sample, separates the chemical fragments produced, and then identifies those constituents.
To review the technique's effectiveness, Navarro-González and his coll