Scientists continue to explore Mars for elusive signs of life. A new tool should help in the hunt. The Mars Organic Analyzer (MOA) can detect and identify amino acids with 1,000 times greater sensitivity than the Viking probes that landed on the Red Planet in 1976.

Alison M. Skelley of the University of California at Berkeley and her colleagues designed the briefcase-size MOA, which includes laser spectroscopy, tiny pumps, valves and fluid channels. In laboratory samples, the new system detected amino acids present in parts per trillion. Analysis of soil samples from the Atacama Desert in Chile, the driest place on Earth, identified acids such as valine and glycine, along with glutamic and aspartic acid in concentrations ranging from 10 to 600 parts per billion. The researchers then took the MOA to Panoche Valley, Calif., to test samples of the mineral jarosite, patches of which were discovered on Mars last year by the rover Opportunity. The device passed its field test, detecting amino acids at 70 parts per trillion.

The MOA is being developed for the European Space Agency's (ESA) ExoMars mission, scheduled to launch in 2009. "ExoMars will be ESA's first mission to carry an exobiology payload, a set of instruments specifically designed to search for life," says Jorge Vago, ExoMars study scientist. "Our intention is to define a multi-instrument package that will be able to fulfill a number of key tasks."