Mars, often called “The Red Planet,” has captivated human imagination for centuries. Its distinct reddish hue, visible even from Earth, has made it a subject of fascination. This allure stems from its intriguing similarities to our own world, prompting curiosity about its past and potential to harbor life beyond Earth. Humanity’s gaze remains fixed on Mars, driven by a quest to unravel its mysteries.
The Martian Environment
The Martian landscape is characterized by striking geological features, including vast plains, towering volcanoes, and immense canyon systems. Olympus Mons, a shield volcano, stands as the largest known volcano in the solar system. Valles Marineris, an expansive canyon network, stretches for thousands of kilometers across the planet’s equator. These features provide clues to a dynamic past, suggesting significant geological activity.
Mars possesses polar ice caps composed of water ice and frozen carbon dioxide, which grow and recede with the changing seasons. The planet’s atmosphere is exceedingly thin, roughly 1% the density of Earth’s, and is composed primarily of carbon dioxide. This thin atmosphere contributes to extreme temperature variations on the surface, which can swing from approximately 20 degrees Celsius (68 degrees Fahrenheit) at the equator during summer to as low as -140 degrees Celsius (-220 degrees Fahrenheit) at the poles in winter.
Evidence indicates liquid water once flowed across the Martian surface, shaping river valleys, lakebeds, and deltas billions of years ago. Although liquid water is unstable on the surface today due to low atmospheric pressure and cold temperatures, significant reserves of water ice are present beneath the surface, particularly at higher latitudes and within the polar caps. The discovery of subsurface ice and minerals formed in the presence of water, such as clays and sulfates, supports a wetter, warmer past, which is a factor in evaluating the planet’s potential for life.
Searching for Life Beyond Earth
The scientific pursuit of life on Mars focuses on identifying biosignatures, which are substances or structures providing evidence of past or present biological activity. These can include complex organic molecules, specific mineral formations, or isotopic ratios that deviate from non-biological processes. Missions to Mars employ sophisticated instruments designed to detect these clues.
Rovers like Curiosity and Perseverance are equipped with drills to collect samples from below the surface, protecting them from harsh radiation and oxidizing conditions that can degrade organic material. These samples are analyzed by onboard laboratories, which identify specific organic molecules and minerals. For instance, the Sample Analysis at Mars (SAM) instrument on Curiosity has detected various organic molecules, including thiophenes, benzene, toluene, and small carbon chains, within sedimentary rocks in Gale Crater.
The presence of water, both past liquid and present as subsurface ice, is a primary driver in the search for Martian life. Discoveries of ancient riverbeds and lake deposits suggest Mars once had environments that could have supported microbial life. The detection of organic molecules, while not direct evidence of life, indicates that life’s building blocks exist on Mars and could have persisted. These findings, coupled with subsurface water ice, point to specific regions as targets for future exploration focused on habitability.
Mars is considered a habitable candidate due to its past liquid water, organic molecules, and internal heat that could sustain subsurface water environments. Scientists are interested in subsurface environments, where life might be shielded from surface radiation and extreme temperatures. This guides the selection of landing sites and the design of future missions.
Journey to the Red Planet
The exploration of Mars has been a long-standing ambition, primarily advanced through robotic missions providing invaluable data. Early successes included the Viking landers in the 1970s, which conducted initial investigations into the Martian atmosphere and surface, attempting to detect signs of life. Later missions, such as the Mars Exploration Rovers Spirit and Opportunity, launched in 2003, characterized the planet’s geology and climate history. They also searched for evidence of past water activity.
The Curiosity rover, which landed in 2012, explores Gale Crater, analyzing rocks and soil to determine if Mars ever had conditions favorable for microbial life. Its successor, Perseverance, which arrived in 2021, is collecting rock and regolith samples for eventual return to Earth for direct laboratory analysis. These robotic explorers serve as precursors, gathering data for planning future human expeditions, assessing risks, and identifying potential resources for astronauts.
Sending humans to Mars presents immense challenges requiring innovative technological solutions. The journey is lengthy, typically six to nine months one way, exposing astronauts to prolonged radiation from solar flares and cosmic rays, which can cause health risks. Maintaining crew health and psychological well-being over an extended mission in deep space is a complex undertaking. Limited resources carried from Earth necessitate developing systems for in-situ resource utilization (ISRU), such as extracting water from Martian ice to produce oxygen and rocket fuel.
Establishing a human presence on Mars will require sophisticated habitats capable of protecting astronauts from the harsh environment. These habitats must be largely self-sustaining, recycling air and water, and potentially growing food. Long-term visions for Mars exploration include establishing permanent research outposts and human settlements. These goals drive ongoing research and development in propulsion, life support, and robotics.
References
NASA. “Curiosity Rover Finds Organic Molecules on Mars.” Accessed July 29, 2025.