Scouting for life on Mars


In 2012, a Dutch foundation called Mars One announced plans to establish a permanent human colony on Mars, with the first settlers arriving in 2022. The company hoped to fund the operation primarily by selling broadcasting rights to a series of short films documenting the astronaut selection process and their one-way journey to Mars. More than 200,000 people expressed interest in becoming the first settlers, with several thousand completing the initial steps of the selection process. After raising tens of millions of dollars, Mars One ultimately went bankrupt in 2019 without ever launching a rocket or producing a documentary.

Although interplanetary space travel may sound like science fiction, NASA hopes to send astronauts to Mars by the 2030s. In mid-February, they landed the latest in their series of rovers on the red planet to push that goal forward. Despite the ongoing global pandemic, the Perseverance rover launched from Florida on July 30, 2020. Some of the final preparations were completed from the living rooms and backyard patios of NASA engineers. The timing was critical, because Earth and Mars only have a close approach every 26 months. Even then they are more than 35 million miles apart, or about 150 times the distance to the moon. The new rover completed the journey in just over six months.

The primary goal of Perseverance is to search for geological evidence of primitive life on Mars. Previous NASA rovers found clear indications that liquid water played an important role in shaping the surface of Mars in the past. If that water helped nurture certain types of bacteria billions of years ago, the hope is that Perseverance can find some fossil evidence of those life forms in Martian rocks. Although the rover has a broad array of instruments designed for this purpose, it can’t possibly conduct all of the experiments that would be required to detect ancient life on Mars unambiguously. So Perseverance has another capability that was missing from earlier rovers.

“A very important objective of the mission is to collect samples that are to be stored in small containers and cached for collection by a future sample return mission,” says Bill Farrand, a research scientist and head of the Center for Mars Science at the Space Science Institute in Boulder.

After studying geology as an undergraduate, Farrand did his graduate work at the Lunar and Planetary Laboratory in Tucson, Arizona. He became an expert in hyperspectral imaging, a technique that can remotely identify minerals using special images that are sensitive to many different types of light. After finishing his doctorate, he worked on some hyperspectral imaging projects in the private sector, eventually bringing him to Boulder in 1995. When NASA sent its first rover to Mars in the late 1990s, Farrand started applying his expertise to new observations of the red planet, and ended up working with the Spirit and Opportunity rovers.

“With both rovers, we found abundant evidence of rocks that had been altered through the action of water. In its early history, water was very active in affecting the mineralogy of the planet,” he explains.

In addition to searching for signs of ancient life and preparing samples for eventual return to Earth, Perseverance also hosts some technology demonstration projects. The most visible of these experiments is a small helicopter named Ingenuity, which will soon attempt the first rotorcraft flight on another planet. The small vehicle, about the size of a toaster but with blades four feet across to keep it aloft in the thin Martian atmosphere, has a high-resolution camera but no scientific instruments. If Ingenuity does manage to fly, future drones may gather their own scientific data or serve as scouts guiding their rovers to the most promising nearby geological sites.

The coolest technology demonstration project on Perseverance may not be as flashy as a space helicopter, but it is far more important for the future of human exploration on Mars.

“It has an instrument that will test a process for generating oxygen from the Martian atmosphere,” Farrand says. “Future missions could use this capability to produce part of the fuel for a return trip to Earth. That would be a huge thing, making round-trip missions much more feasible.”

Although thousands of people signed up for a one-way trip to the red planet with Mars One, most astronauts would prefer to return to Earth at the end of their mission. The ability to manufacture oxygen, and ultimately rocket fuel, from resources that already exist on Mars would make more room for other necessities of the long journey. The most efficient mission plans require 18 months of travel time plus 500 days on the planet itself, while more expensive options would aim to complete the trip in just over eight months. Keeping the mission duration as short as possible will help astronauts survive the harmful cosmic radiation in interplanetary space.

Perseverance was designed to work on Mars for a minimum of two years, but its predecessor, the Curiosity rover, is still running strong after eight. NASA releases images and information about new discoveries frequently, so stay tuned to as the mission continues.  

Travis Metcalfe, Ph.D., is a researcher and science communicator based in Boulder. The Lab Notes series is made possible in part by a research grant from the National Science Foundation.


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