Searching for life on Mars just got a whole lot easier

For decades, the search for extraterrestrial life has relied on complex missions, new instruments, and billion-dollar budgets.

But now, a Ph.D. student and his supervisor at Imperial College London have shown that a device already sitting on Mars could answer one of humanity’s biggest questions: Is anything alive out there, right now?

The breakthrough comes from Solomon Hirsch and Professor Mark Sephton of Imperial’s Department of Earth Science & Engineering.

The gas chromatograph-mass spectrometer (GC-MS) is an instrument that is already installed on the Curiosity rover and planned for use on the ExoMars Rosalind Franklin rover. The team realized that this common piece of equipment can be used in an entirely new way.

Old instruments, new tricks

“Space agencies such as NASA and ESA don’t know their instruments can already do this,” Sephton said. “Here we have developed an elegant method that rapidly and reliably identifies a chemical bond that shows the presence of viable life.”

“The Curiosity rover just turned 13 on Mars, but who says you can’t teach an old dog new tricks.”

The GC-MS has a long pedigree in planetary science, with earlier versions flying on the Viking missions of the 1970s. Traditionally, scientists have used it to analyze gases released from rocks and soils.

But Hirsch and Sephton discovered it could also detect fragile molecular bonds inside the membranes of living cells – a marker of life that is present only while an organism is alive or has very recently died.

Unmistakable signals of living cells

The technique focuses on intact polar lipids (IPLs), the molecules that make up the external membranes of bacteria and more complex cells.

These molecules degrade within hours of death, making them a reliable sign of living organisms. When fed into the GC-MS, IPLs leave behind a sharp, unmistakable spike on the instrument’s readout.

Researchers unexpectedly found a clear biosignature in polar lipids using GC-MS, with equipment already deployed on space missions. If scientists ever detect such a spike on Mars or another world, it will provide direct evidence of active life rather than long-extinct biology.

“If we find signs of life beyond Earth, the first question will be: Is it living right now?” Hirsch said. “It’s thrilling to think that the technique we developed here could be used to help answer that question.”

Searching for life in Mars’ extremes

Mars is not a welcoming place for life. Its thin atmosphere, freezing surface temperatures, and constant radiation from space make survival difficult.

Hirsch admits that expectations of finding organisms on the planet’s surface are low. But he points out that life is resourceful. “Life finds amazing ways to survive in extreme circumstances,” he noted.

Future missions will also dig deeper into Mars’ crust, where conditions may be more favorable. The Rosalind Franklin rover, part of the delayed ExoMars mission, will drill several feet beneath the surface, where microbes could remain shielded from radiation and potentially active.

Beyond Mars, icy moons like Europa and Enceladus are even more promising. They are known to host subsurface oceans and erupt plumes of water vapor into space.

Sephton envisions the method being applied there too. “Our active life detection method could be deployed on Mars and the plumes of icy moons in the outer solar system, or in samples returned to Earth from potential alien biospheres,” he said.

How Mars science helps on Earth

The method could also help right here at home. Teams preparing to analyze samples returned from Mars are planning multimillion-dollar facilities to screen for possible life.

A quick and simple GC-MS test would make the task more efficient, flagging which samples deserve deeper analysis.

Sephton sees the technique as both cost-effective and versatile. Instead of designing entirely new instruments for each mission, scientists could repurpose existing ones to do more than originally intended.

It’s an approach that may accelerate discoveries without requiring decades of waiting for the next mission to launch.

The future of Mars and beyond

Whether or not life is discovered, the technique itself represents a leap forward. It shows that sometimes the tools for transformative science are already in our hands – it just takes a new perspective to see them differently.

The search for extraterrestrial life is often portrayed as a grand adventure, requiring futuristic technology and vast budgets.

Hirsch and Sephton’s work offers a humbler but no less profound possibility: the answer to one of humanity’s oldest questions may already be riding around the Martian surface, waiting to be asked the right question in the right way.

As Hirsch put it, the possibility remains remote but real: “Our expectation of finding things alive on the Martian surface is low due to the hostile temperature and radiation conditions. Still, we aren’t ruling out the possibility.”

And if life does exist, this new approach may be the simplest way to prove it.

The study is published in the journal npj Space Exploration.

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