The quest to find life on Mars is at the forefront of NASA's scientific ambitions for the first human mission to the Red Planet. This pursuit carries the weight of centuries-old curiosity about the existence of life beyond Earth. A recent report from the National Academies has addressed a fundamental question: when humans finally land on Mars, the primary scientific objective should be to search for evidence of past or present Martian life, taking precedence over all other goals, including understanding the effects of Mars on human health.
This recommendation places astrobiology at the heart of an endeavor that will be one of humanity's most ambitious and complex. It means that landing site selection and mission planning will prioritize finding biosignatures or prebiotic chemistry, rather than solely demonstrating technological advancements or preparing for colonization.
The focus of the search for life will be on Mars' ancient riverbeds, still visible on the planet's surface. The National Academies committee has identified eleven ranked science objectives for human missions, with the search for life taking the top spot. Following this, the objectives include characterizing Mars' water and carbon dioxide cycles to understand its evolution, mapping its geologic record, and studying the impact of the Martian environment on human physiology and psychology.
Further down the list are objectives related to long-term settlement, such as exploring resources for in-situ utilization and understanding the effects of the Martian environment on plant and animal reproduction. These priorities reflect a deliberate choice to prioritize fundamental scientific discovery over practical concerns.
The report outlines four potential strategies for human exploration, each consisting of three linked missions targeting specific objectives. The top-ranked approach suggests a sequence of missions, starting with a 30-sol human landing, followed by an uncrewed cargo delivery, and culminating in a 300-sol extended mission, all within a single exploration zone of about 100 kilometers. This campaign would require a range of scientific instruments, drilling equipment, meteorological stations, and a habitat laboratory for detailed analysis.
The second-ranked campaign takes a more flexible approach, optimizing for measurements across multiple science objectives rather than a single ideal site. The third campaign focuses on the search for life by targeting a site with access to liquid water, allowing crews to collect and analyze samples. The fourth option proposes three short missions to explore diverse Martian environments, including igneous geology and regions with evidence of ancient water.
The report recommends that NASA continue developing planetary protection protocols, include surface laboratories, and return samples from human missions. It also emphasizes the importance of exploring the collaboration between humans, robots, and artificial intelligence on Mars, recognizing the potential for scientifically productive missions through this sophisticated partnership.
