The search for life on Mars could accelerate thanks to the MARSE mission concept

In recent research, presented at the 55th Lunar and Planetary Sciences Conference (LPSC), discusses the Mars Astrobiology, Resource, and Science Explorers (MARSE) mission concept and its simplified high-impact energy landing device (SHIELD), which offers a more versatile and lower-cost method searching for past or present life on the Red Planet, specifically using four rovers at four different landing sites scattered across the surface of Mars. The concept comes as NASA's Curiosity and Perseverance rovers continue to tirelessly explore the surface of Mars at Gale Crater and Jezero Crater, respectively.

Universe Today discusses the MARSE mission concept with the study's sole author, Alex Longo, a master's student in the Department of Earth, Marine and Environmental Sciences at the University of North Carolina at Chapel Hill, and talks about the motivation behind MARSE, the choice of landing sites, significant implications, current work, and what's next. steps to turn MARSE into a real mission. Longo draws on more than a decade of experience searching for landing sites on Mars, and also has several publications under his belt, including a number of scientific abstracts, articles and a Kindle book. So what was the basis for developing the MARSE mission concept?

“The main goal of the MARSE concept study was to reduce the cost of access to the surface of Mars,” Longo says in interview Universe Today. “Flagship rovers like Curiosity and Perseverance are extremely capable vehicles. However, since they cost over a billion dollars apiece, we will only be able to visit one or two sites on Mars every decade.” Like Earth, Mars is a surprisingly diverse planet. Using satellites in orbit, we have mapped a variety of ancient environments that may have been habitable in the distant past. However, the resolution of orbital imagery and spectra is limited, and they sometimes cannot predict what a field geologist (or, in the case of Mars, a rover driven by geologists) on the ground will find. Even on Earth it is difficult to find early biosignatures, and with relatively little weathering and erosion, I would not be surprised if the same was true on Mars. MARSE was intended to present one possible solution that would allow planetary scientists to explore more places on Mars within a realistic budget.”

The car-sized rover Curiosity landed in Gale Crater on August 6, 2012. The mission's website states that as of January 27, 2024, Curiosity had traveled 31.27 kilometers, significantly exceeding its expected operating life of one Martian year, or 687 Earth days. Gale Crater was chosen as the landing site because of ample evidence that it once contained liquid water in Mars' ancient past. Scientists estimate that Gale Crater was formed as a result of a collision approximately 3.5-3.8 billion years ago. During its stay at Gale Crater, Curiosity used its suite of scientific instruments to discover evidence of liquid water in Gale Crater and evidence that Mars once had the building blocks for life, including carbon, oxygen, nitrogen, phosphorus and sulfur .

The car-sized Perseverance rover landed in Jezero Crater on February 18, 2021, and the mission's website states that Perseverance has traveled a total of 25,113 kilometers as of March 28, 2024. Although Perseverance and Curiosity share a similar design, the main improvement was the delivery of the Ingenuity helicopter to Mars, which became the first robotic explorer to fly electric on another planet, and completed dozens of flights before it was finally grounded after being damaged. one of the rotor blades during the last landing in January 2024. Like Curiosity's Gale Crater, Jezero Crater was chosen as Perseverance's landing site because of strong evidence that it once contained a massive body of liquid water, as evidenced by the enormous fan-delta deposits that , were likely the entry point for liquid water billions of years ago. During its stay at Jezero Crater, Perseverance used its suite of scientific instruments to identify ancient volcanic rocks, sediments from ancient lake beds, convert carbon dioxide (a major component of Mars' atmosphere) into oxygen, and even used its powerful microphones to record the sounds of Mars. Given the incredible science conducted by Curiosity and Perseverance, what are the most significant implications for the MARSE mission?

“The most significant implication of this research is the possibility of creating a small rover that can characterize an unexplored location on Mars,” Longo tells Universe Today. “There have been several proposals for low-cost Mars rovers such as SHIELD. MARSE demonstrates that they can deliver scientific payloads.” Each MARSE rover weighs just 15 kilograms and is about the size of a microwave oven. If we can figure out how to land rovers like these on Mars, it will help expand and democratize Mars exploration. We are already seeing a paradigm shift in lunar exploration with the Commercial Lunar Payload Services (CLPS) program.”

Although Curiosity and Perseverance have successfully explored their landing sites in detail, each mission costs billions of dollars (Curiosity: ~2.7 billion). Thus, cost alone allows for only one rover to be used on each mission, and their landings occurred almost seven years apart. As noted, one of the goals of the MARSE mission concept is to land four rovers on four separate landing sites – Columbia Hills, Milankova Crater, Maurts Valley and Terra Sirenium. At the same time, the Columbia Hills was the landing site of the Spirit rover during its mission from 2004 to 2010, and other places have never been explored by either rovers or spacecraft. But how were the landing sites chosen and are other landing sites being considered?

Longo told Universe Today: “We didn't necessarily choose these four landing sites. We just wanted to illustrate the range of studies that can be done with this approach.” All four sites listed have been identified in peer-reviewed papers and previous landing site studies, so we know they have high scientific potential.”

Longo goes on to tell Universe Today that SHIELD will be designed to “land on any flat area on Mars below the reference point (0 km altitude on Mars; equivalent to sea level on Earth), so you can easily swap out one or more of them landing sites of your choice,” with Longo noting that one of his personal favorite landing sites would be Valles Marineris, the largest and deepest canyon in the solar system. Longo recounts years of research by Dr. Steven Ruff of Arizona State University, who conducted analogue studies comparing sediments from the Columbia Hills hot spring on Mars with similar characteristics from the El Tatio hot spring in Chile and concluded that microbial communities can thrive in these places.

As noted, Curiosity and Perseverance landed on Mars almost nine years apart, in 2012 and 2021 respectively, but their missions began development almost a full decade earlier. Both rovers are part of NASA's Mars exploration program, with the Curiosity mission approved in 2003 and the Perseverance mission announced in 2012. Once a mission is approved, NASA spends years designing and building each Mars rover to ensure all its systems are operating at full capacity before it is delivered and loaded onto the launch vehicle. This includes tests aimed at analyzing the rovers' endurance, exposure to harsh environmental conditions, durability and many others. So if the MARSE mission gets the green light, it could be nearly another decade of development, construction and testing before their microwave-sized rovers touch the surface of Mars. So what are the next steps in terms of validating MARSE for a real mission?

“Unfortunately, the future of MARSE and SHIELD is uncertain,” Longo tells Universe Today. “This concept was developed with the support of the SHIELD team at JPL, led by Lou Giersch and Nathan Barba. They were doing phenomenal, cutting-edge work, and I was grateful for the opportunity to work with them. Unfortunately, last month JPL was forced to make massive budget cuts and layoffs due to uncertainty about the future of the Mars Sample Return mission, which accounts for the majority of the center's budget. With JPL's future priorities in uncertainty, we have paused development of the MARSE concept.”

While there is uncertainty surrounding the MARSE mission, it is important to note that space exploration missions often take decades to go from simple concept to actual hardware, and then several more years before launch. This is evidenced by the missions of the Curiosity and Perseverance rover: almost ten years passed from the approval of each of them to the landing on Mars. Moreover, it is not uncommon for mission applications to go through several attempts before being approved because NASA has very strict criteria for approving missions, including cost, timing, science objectives, and long-term implications for science. Despite the prospects, this did not stop Longo from continuing to work on the MARSE mission concept.

“Developing the mission concept was a very rewarding experience, and it was an honor to work on this concept with the SHIELD team,” Longo tells Universe Today. Even if it's ten years from now, I hope someone will eventually implement a low-cost, reusable mission to Mars for geology and astrobiology.” With the Mars Sample Return project completed, the next logical steps in Mars exploration are to explore more of the planet, more “A deep understanding of its history and learning what Mars can tell us about our own planet's past. If we want to have a thriving space program, we need to be creative and implement bold ideas, and I love working with scientists and engineers who are doing just that.” .

Will the MARSE mission be able to explore the Red Planet in the coming years and decades? Only time will tell, and that's why we do science!