Abigail Fraeman, PhD, has operated two of NASA’s Mars rovers, Opportunity and Curiosity, seeking to uncover the secrets held underneath the planet’s layers of sand. Bruce Jakosky, PhD, is currently the associate director for science in the Laboratory for Atmospheric and Space Physics, and has worked on several projects studying the climate of Mars. 

At the U of T Astronomy & Space Exploration Association’s 20th Annual Symposium, themed Mars: The Quest for Human Habitat, Fraeman and Jakosky shared insights into the exploration of Mars. 

Rovers roaming the red planets

Has there ever been life on Mars? To answer this question, Fraeman explained, three Mars rovers looked into whether the planet had three key features for habitable conditions: long-lived water, as in, water that has run or existed for a long time; the presence of key chemical elements and nutrients for life; and the availability of material that can be used for energy.

Spirit and Opportunity were sent to Mars to look into its possibility of long-lived water. Spirit, the first to land, discovered carbonate minerals in the rocks, indicating past warm water environments with a neutral acidity. Not long after, Spirit became lodged in the soil, ending its six-year journey. 

Scientists studied the surface beneath Spirit, seeing that the layers of soil were of decreasing salt solubility, indicating the minerals were deposited by thin films of water. Additionally, the rover uncovered remnants of past volcanic activity, including hot water, gas and vapour vents, as well as remnants of hot springs alongside salts and silica formations, suggesting potentially habitable conditions.

Later, Opportunity landed in a crater infested with the mineral hematite, which was later discovered to be a result of sand dunes cemented by rising waters. As this rover made its way to another crater, Endeavor, evidence of clay and gypsum minerals — which are precipitated from moving water — was found. The observations and data collected by these missions allowed scientists to affirm that liquid water once existed on Mars.

The next rover sent to Mars was Curiosity, whose discoveries have reshaped our understanding of the red planet’s past habitability. Upon landing in Gale crater, the rover immediately encountered conglomerates, a type of sedimentary rock that indicates a past riverbed environment. 

As Curiosity ventured further, ancient lakebed sediments complete with essential elements for life revealed evidence of water on Mars. Drilling into the surface, Curiosity received samples that were revealed to be rich in organic molecules and vital minerals, shedding light on Mars’ potential to support life. 

Yet, the mystery remains regarding the factors driving modern dry conditions and climate fluctuations on the red planet.

The slow process of controlling these rovers and the lack of human accessibility to Mars are major limitations to the speed of exploration and discoveries. Fraeman hopes that these rovers will one day pave the way for human exploration of Mars. Until then, Curiosity’s ongoing mission will be closely followed for further revelations.

Living on Mars — is it still a dream?

The future of Mars exploration is marked by ambitious endeavours, including Lockheed Martin’s “Mars Base Camp” and SpaceX’s Starship, as well as a farther-reach scientific outpost. In his presentation, Jakosky elaborated on the significant complications of heading toward human missions on Mars.

At the heart of Mars exploration lies the pursuit of scientific discovery — particularly in the search for environmental conditions that can support life, as asserted by NASA. The possibility of life existing on Mars would offer profound insights into the origins and evolution of life in the universe when compared to the course of life here on Earth.

Rovers like Perseverance allowed scientists to confirm that liquid water was once on Mars, as they found traces of the essential minerals for life — carbon, hydrogen, nitrogen, oxygen — in the planet’s atmosphere, and were able to predict that it was likely Mars once had a moderate temperature as it is required for such minerals to exist. With these findings, NASA’s current objectives involve understanding what led to the change of Mars’ climate, the geological processes that take place, and the relationship between the surface and inner layers of the planet — all of which could be answered faster with humans on Mars itself. 

In order to institute human missions on Mars, though, we must solve several technical problems. What can ensure that humans have enough resources to live there while also avoiding radiation damage and potential fatality? What procedures would be followed when something goes wrong? Financial issues also come into play given that the estimated costs for such missions lie anywhere within the range of 100 billion up to a trillion dollars, according to Jakosky.

With the evidence pointing at Mars being habitable, the big question is: how would we terraform Mars? In other words, would it be possible to alter Mars’ environment and atmosphere to resemble that of the Earth? Through the MAVEN spacecraft, for which Jakosky is the principal investigator, scientists have been studying how Mars’ atmospheric gas has been lost to space. Astro-scientists believe that this is a major mechanism responsible for the change in Mars’ climate.

Astrophysicists have also crucially hypothesized that mobilizing enough Martian carbon dioxide — found in Martian polar ice caps and attached to individual dirt grains in a process known as adsorption — into the atmosphere could warm the planet and allow liquid water to be present.

SpaceX founder Elon Musk has labelled Mars as a plan-B planet, in the case that the Earth’s conditions were no longer liveable. However, Earth will always be much easier to terraform back into a living condition than it would be to terraform Mars, given the latter’s complex environment and many mysteries. Therefore, Musk’s stirring anticipation of living on Mars may only have negative effects, as people will start taking less and less care of the Earth. 

Still, Jakosky sees significant potential in the initiation of human missions on Mars. Combined with the information presented by Fraeman about the geobiology of Mars, the mysteries of the Martian surface are slowly being uncovered for human exploration. The future of Mars exploration holds immense scientific promise.