MADRID, 14 (EUROPA PRESS)
Equipment already installed on the Curiosity rover and planned for future use on the ExoMars Rosalind Franklin rover can be used to easily assess the existence of active life on Mars.
Imperial College London PhD student Solomon Hirsch and his supervisor, Professor Mark Sephton, have realized that an existing instrument could be used to detect signs of life at a fraction of the cost of developing new missions and instruments. It has the potential to be used to detect living organisms on other planets or moons.
The instrument, called a gas chromatograph-mass spectrometer (GC-MS), has been installed on Mars probes since the mid-1970s, with preliminary versions on the Viking I and Viking II landers.
Hirsch and Sephton determined that it could be used to detect a chemical bond within cell membrane molecules present in many living and recently deceased organisms. The research is published in npj Space Exploration.
"Space agencies like NASA and ESA don't know their instruments can already do this," Professor Sephton said in a statement. "We've developed an elegant method that quickly and reliably identifies a chemical bond that demonstrates the presence of viable life," he added. "The Curiosity rover has just celebrated 13 years on Mars, but who says you can't teach an old dog new tricks?"
UNIQUE SEQUENCE OF ATOMS
The new method detects a unique sequence of atoms that binds the constituent molecules of the outer membranes of living bacteria and eukaryotic cells. These constitute the vast majority of biological matter on Earth and include the types of life forms that scientists would also expect to find beyond our planet.
The characteristics of these bonds, present in molecules called intact polar lipids (IPLs), show up as a clear peak in a graph generated by the GC-MS instrument. Hirsch says, “When we introduced the intact polar lipid compounds into our gas chromatograph-mass spectrometer (GC-MS), we didn’t know what to expect, as these compounds are typically analyzed using other techniques. The characteristic signature we identified provides a clear indicator of viable life thanks to space-based equipment already used on numerous extraterrestrial missions. If we find evidence of life beyond Earth, the first question will be: Does life exist right now? It’s exciting to think that the technique we developed here could be used to help answer that question.”
Once an organism dies, its IPL bonds decay within hours, after which they can no longer be detected and a peak no longer appears on the instrument reading.
The method is not only useful for detecting life elsewhere in the solar system, but also for protecting life on Earth. Groups of scientists from around the world plan to invest millions of dollars to detect signs of active life in samples brought back from Mars. Their task will be facilitated by a rapid and simple method for detecting life.
Professor Sephton says: "Our method of detecting active life could be implemented on Mars and in the plumes of icy moons in the outer Solar System, from where data could be sent back to Earth for interpretation, or on samples brought back to Earth from potential extraterrestrial biospheres."
Hirsch adds: "Our expectation of finding living beings on the Martian surface is low due to the harsh temperature and radiation conditions. Still, we don't rule out the possibility: life finds amazing ways to survive in extreme circumstances. Furthermore, future missions like ExoMars plan to drill meters deep into the planet's surface, where the probability of finding active life is significantly higher."
