Study suggests Martian rocks may be saturated with fuel-building ingredients.

Onsite production of materials such as fuel and construction resources have been under study to extend the distances and livability of space exploration. Rockets that can make or collect fuel can go farther, and astronauts that don't need to bring their own tools and building materials can stay in space longer.

This use of the surrounding environment to produce new materials has its own discipline and related funding at NASA, called in-situ resource utilization (ISRU).

"The human and robotic exploration of the solar system presently is limited by the amount of resources that accompanies the spacecraft. Long-term exploration will require humans and robotic spacecraft to 'live off the land', generating resources such as fuel, water, and food from in-situ sources," NASA explains on its website. "JPL's Electrochemical Research, Technology, & Engineering Group is engaged in ISRU research, such as developing electrochemical methods for converting carbon dioxide to fuels."

Previous studies have demonstrated that ISRU can supply the fuel and oxygen for longer Moon missions, more so in future Mars missions, by harvesting readily available carbon dioxide from the Martian atmosphere, minimizing or even eliminating the need to transport supply from Earth to Mars.

To successfully support these missions, however, large amounts of fuel and oxygen (NASA suggests 10 megatons per Martian year) will still be needed, necessitating the development of high-volume approaches to carbon dioxide reduction – something that Earth as a whole could make good use of today.

It takes a prohibitive amount of fuel to land a spacecraft on Mars and more to bring it home. Scientists have long known that bringing enough to power a trip back would be inefficient, and this awareness has pushed researchers and engineers to find the best solution.

Now, an abundance of CO2 that can be converted into fuel has been discovered in Martian rocks.

"Given the abundance of ultramafic rocks and smectite in the Martian upper crust and the growing evidence of organic carbon in Martian sedimentary rocks," wrote MIT planetary sciences PhD Joshua Murray and MIT geology professor Oliver Jagoutz, co-authors of a new paper published in the journal Science Advances. "Such a reservoir could be used as an energy source for long-term missions. Our results further illustrate the control of water-rock reactions on the atmospheric evolution of planets."

The researchers estimate that about 80% of CO2 from the early Martian atmosphere may now be trapped in carbon-based organic compounds at the rocky surface, ready to be extracted and converted into rocket fuel in a process already well understood back home on Earth.

"Based on our findings on Earth, we show that similar processes likely operated on Mars, and that copious amounts of atmospheric CO2 could have transformed to methane and been sequestered in clays. This methane could still be present and maybe even used as an energy source on Mars in the future," said Jagoutz.

"At this time in Mars' history, we think CO2 is everywhere, in every nook and cranny, and water percolating through the rocks is full of CO2 too. These smectite clays have so much capacity to store carbon," explained Murray. "So, then we used existing knowledge of how these minerals are stored in clays on Earth, and extrapolate to say, if the Martian surface has this much clay in it, how much methane can you store in those clays?"

Mars could one day serve as a filling station for travel further out into our solar system.