Feature: Life Beyond Earth

What's really underneath the Martian surface?

In the dark and musty garage of the Electrical and Computer Engineering Research Facility lies the brainchild of the student group Space Exploration Alberta Robotics (SPEAR). With its 6.5 kilogram battery and robotic scooper, SPEAR’s rover was built to traverse rugged Mars-like terrain: surveying the landscape, extracting Martian resources, and searching for life.

As I studied the rover’s motorized wheels and on-board computer, André Ulliac and Noel Gore carefully laid out a series of intricately cut metal bars and hinges for a metre-long robotic arm. When assembled, the arm will be equipped with a remote-controlled camera, a robotic hand precise enough to type on a keyboard, and a motorized shoulder that can lift a five-kilogram weight at a full arms-length away. The team named the rover TARS, after the tactical robot from Intersteller.

Ulliac is a second-year mechanical engineering student and SPEAR’s mechanical team lead. Beside him is Gore, a fourth-year geophysics student and the science team lead. While Ulliac oversees the assembly of gears and wires into the Martian rover, Gore spends his time poring over the details of the onboard instruments, ensuring the rover can perform a range of experiments.

The U of A’s SPEAR team is composed of over 100 members, each pitching in during their spare hours to create the U of A’s first student-built Martian rover. The team recently competed in the Canadian International Rover Challenge and will be entering another competition in the Utah desert come summer 2019. Both Ulliac and Gore joined SPEAR to become more involved with space research on campus. The field can be difficult for young scientists to break into, but student groups like SPEAR can help them build connections with engineering firms and space agencies.

When I asked Ulliac and Gore why they both wanted a career in space exploration, they said part of it was the thrill of the challenge. Nearly two-thirds of spacecraft sent to Mars fail before completing their mission, and Gore said there’s a certain prestige that comes with being able to achieve what many cannot. But apart from advancing scientific research, the duo said space exploration also fills an innate human curiosity. Only by exploring beyond the confines of Earth can we answer the fundamental question: are we alone in the universe?

Mars is one of Earth’s closest neighbours. While its red surface appears barren, the presence of polar ice caps and its proximity to the sun gives it the highest chance of harbouring life within the reachable solar system. If life does exist elsewhere, many think our search should begin on Mars.

Growing up, my understanding of extraterrestrial life came primarily from watching FBI agents Mulder and Scully in The X Files. Additional lessons were supplied by the movies Signs, The Thing, Invasion of the Body Snatchers, and of course, the Alien franchise. Even when I think of extraterrestrial life now, a certain archetype comes to mind: amorphous creatures with acid for blood and an unquenchable desire to conquer Earth. But the more I spoke with U of A biologist Brian Lanoil who had worked on the astrobiology team at NASA’s jet propulsion lab in Pasadena, California, the less my concept of alien life seemed able to withstand scientific scrutiny. If Martian life exists, Lanoil said, it’s likely microscopic.  

While the surface of the red planet appears largely barren now, many researchers believe ancient Mars’ craters and valleys likely carried freshwater lakes, rivers, and possibly even oceans about four billion years ago. Its atmosphere and surface temperatures would have been much more similar to Earth — and likely capable of supporting life. But in the absence of a strong magnetic field, the planet was left exposed to harsh solar winds from the sun that have stripped the planet of these luxuries over time. What remains are two polar ice caps and the wide expanse of sand, dust, and dirt in between.

Without any bodies of water or a thick atmosphere to store heat, surface temperatures fluctuate wildly between day and night. Under the summer sun, the planet’s equator can reach upwards of 20 C, only to drop to -70 C when dusk falls. Lacking a prominent ozone layer, the planet is subjected to harsh ultraviolet rays. The average human on Earth receives only 1.7 millirads of radiation each day, but on Mars, that value is almost 26 times higher, reaching levels of up to 44 millirads.

It’s clear humans could never survive unprotected in the harsh Martian environment, but that doesn’t mean other living things can’t. To understand the limits of life and whether it could exist elsewhere in the universe, Lanoil said we can begin by utilizing extreme environments on Earth as an analog for other planets. For instance, unlike plants and animals, microbes can survive without oxygen. Many utilize a process called “methanogensis” where energy is generated by reacting chemicals such as carbon dioxide and hydrogen to create methane. These methanogens can be found all across the planet, from swamplands, to deserts, and even in Arctic ice cores. In June 2018, NASA’s Curiosity rover revealed a seasonal cycle of methane production on Mars, reaching maximum methane release during late summer and early autumn. Lanoil said the finding could suggest Earth-like methane-producing bacteria living under the Martian surface.

To understand how life can survive the Martian cold, researchers use the microbe Planococcus halocryophilus, which grows at temperatures of -25 C in harsh Arctic permafrost. As water freezes, salts are forced out of expanding ice crystals. With enough salt, water stays liquid at temperatures below freezing and microbes can thrive in these veins of salty brine. Lanoil said melted Arctic ice can carry around 100,000 bacterial cells per millilitre. For studying the possibility of life under constant radiation, astrobiologists turn to Deinococcus radiodurans. Its resistance to radiation allows it to populate areas surrounding catastrophic nuclear accidents like Chernobyl and Fukushima Daiichi.

Lanoil says these microbes provide a foundation for scientists to study how similar alien life could survive outside Earth. But regardless of the conditions these microbes can tolerate, Lanoil said none of it could exist without the presence of water and other organic compounds. “As far as if microbes could live on other planets, NASA has this mantra — follow the water,” he said. To determine the availability of these basic building blocks of life, NASA has sent a series of landers and rovers to scour the Martian surface.

In August 2007, NASA’s Phoenix lander found ice underneath a layer of loose soil, confirming the existence of subsurface water. Earlier this year, NASA’s Curiosity rover discovered the existence of organic molecules in three-billion-year-old Martian mudstone, further indicating the possibility of alien life. But to find life itself, Lanoil said researchers will have to dig deeper. Living things need access to liquid water. The best chance of finding that on Mars is underground, where it’s insulated by a layer of dirt and kept from being stripped off by the dry Martian air. Mars averages a temperature of -55 C on most days, and at the poles, temperatures can drop down to -125 C. To determine if liquid water could really exist on the planet, I sought the help of Carlos Lange, an associate professor of mechanical engineering and fluid dynamics expert.

In his tenth-floor office in the Donadeo Innovation Centre for Engineering, Lange started unpacking a wooden box containing a miniature replica of the “tell-tale” used by NASA’s Phoenix lander to measure surface winds. Following the wind would be key to finding liquid water underneath Mars’ surface.

To measure Martian weather, Lange designed the tell-tale with the aid of two student volunteers in the early 2000s. Without an electronic wind sensor available at the time, Lange said the team had to rely on old-school methods. As Lange blew on the replica, an angled mirror revealed a small cylinder on a thread swaying in the wind.

Using the Phoenix lander’s camera, Lange was able to determine the direction and speed of the Martian wind based on the angle at which the cylinder swayed. He said the cylinder was light enough to be moved by a breeze as slow as one metre per second.

The Phoenix mission only lasted a year before the Martian winter destroyed the internal components of the lander in 2008. But Lange says the data he collected shapes his research on Martian storm systems. “We’re trying to model to see where we can find water that becomes liquid,” he said.

“Where water becomes liquid even just for a short period of time, that’s where we should look for life.”

On Earth, much of our weather is driven by the evaporation and precipitation of water into and out of the atmosphere. But without large bodies of water to drive the water cycle, storms on Mars are instead driven by “dust devils,” cyclic air currents that pull dirt and water vapour out from underground. Like tornadoes, the low-pressure zone in the centre cools the ground, keeping any subsurface water frozen. However, where dust devils fail to form, Lange said the frozen brine underground may thaw just enough to create a water pocket where microbes can flourish. These conditions are similar to sea ice in the Earth’s Arctic pole, where water can remain liquid even at subzero temperatures. “We don’t expect life to exist on the surface,” he said. “But underground you are protected not by the ozone or a magnetic field but by a layer of dirt. And if the subsurface ice melts from time to time, you have the conditions for life.”

Just this summer, the Italian Space Agency announced the potential discovery of an under-ground lake. By sending electromagnetic signals onto the Martian surface and seeing what bounces back, the MARSIS radar aboard the European Mars Express Orbiter detected a strange echo above Mars’ southern pole. It’s not clear what it could be, but one possibility includes a 12-metre long vein of subsurface water.

After meeting with Lange, I left his office feeling a newfound optimism in our search for alien life. But if they did exist, how could we prove it? While I continued my pursuit in the safety and comfort of Earth, Lange told me about a new rover that aims to retrieve irrefutable evidence of alien life from Mars. Under his advice, I trekked to the Earth Sciences Building in search of Lange’s colleague: geologist and meteorite curator Chris Herd.

Despite advancements in rover technology, Herd said research into extraterrestrial life remains confined by the types of tests robots can perform. The presence of water, methane, and other organic chemicals as detected by past NASA rovers suggests the possibility of Martian life, but without visible evidence, it remains only a possibility.

To find irrefutable evidence, Herd has been working as one of 11 scientists advising NASA’s upcoming 2020 rover mission. But unlike past projects, Mars 2020 aims to return samples to Earth, where scientists can examine them under the microscope to look for evidence of microbial fossils. The team is focusing their exploration on three potential sites: Jezero Crater, Northeast Syrtis, and Columbia Hills. Each landscape is marked by evidence of liquid water in the distant past. Jezero Crater previously contained a river delta — a formation that occurs when a river meets a larger body of water. Northeast Syrtis and Columbia Hills contains now dormant hydrothermal systems. “On Earth, if you crack open those same features, guaranteed you will see fossilized bacteria,” Herd said.


The Mars 2020 rover will collect approximately 30 samples from one of these sites and preserve them for its return to Earth later that decade. But the challenge will be to ensure the samples do not become tainted with terrestrial contaminants. Scientists call this “planetary protection.” For the evidence to be irrefutable, Herd said researchers must ensure chemical and biological contaminants from Earth are not accidentally carried to Mars where they may be potentially mistaken as extraterrestrial. Likewise, potential alien life, if brought back to Earth, could endanger our planet’s ecosystem. “There’s the potential for Martian samples to harbour actual life active on mars now,” he said. “You don’t want that to be a threat to life on Earth.”

Herd’s was the first lab to develop equipment for analyzing Martian meteorites in a sterile and climate controlled space. Samples are preserved at -30 C to prevent decay and shuttled into a -15 C chamber filled with inert Argon gas for experimentation. He said NASA is working on something similar for Mars 2020.

But for now the only creatures we know of roaming the red surface are purely robotic. Whether life may have scoured the Martian surface in centuries past — or continue to below the rocky landscape — remains to be discovered. Yet, what will the discovery really mean?  It’s hard to imagine how microscopic life on Mars can alter life here on Earth. Yet, there’s something comforting in knowing we might not be alone in this infinite universe, that elsewhere, life thrives as it does on Earth. Maybe it’s the thought of finding something amidst a void of nothing that drives our fascination with space.

“Finding a microorganism growing on Mars isn’t going to revolutionize life on Earth,” Lanoil told me as we ended our conversation. “But it does change our view of the universe, and that’s not an insignificant thing.”

Calvin Chan

Calvin Chan is a cell biology student with a keen interest in science writing.

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