Missions to Find Life on Mars

Mars is our nearest planetary neighbor that potentially housed life in the past or currently houses life. Therefore, it has been the destination of many missions that have attempted to find life within our Solar System. Numerous missions have, since the early 1960s, journeyed to the Red Planet to further our search for extraterrestrial life.

The Spirit and Opportunity rovers, which were part of the Mars Exploration Rover Mission, have immensely enhanced our understanding of the Martian environment. Since landing on Mars in January 2004, these rovers have made extensive geological and atmospheric observations. With their cameras, the rovers have been able to send over 100,000 color and high-resolution panoramic and microscopic images of Martian terrain, rocks and soil to Earth. The rovers, however, have also been able to analyze the Martian environment. The four spectrometers along with the rock abrasion tools on each rover have allowed us to gain insight into the chemical and mineralogical characteristics of Martian rocks and soil. While Opportunity is still currently exploring the surface of Mars, Spirit has not been active since 2010. Together, however, the rovers have explored the Eagle, Endurance, and Gusey craters (among others), and have found evidence of ancient Martian environments that were sculpted by volcanism, contained water, and that were habitable.

The Mars Express Orbiter, part of the Mars Express Mission, is another spacecraft currently exploring Mars. The Mars Express Orbiter has been analyzing the atmosphere and surface of Mars from polar orbit since 2003. It has researched Martian geology, atmosphere, and surface environment. Specifically, it has made efforts to better understand the history of water on Mars as well as the potential for life on Mars. Through its observations, the Mars Express has found evidence of glacial activity, explosive volcanism, and methane gas. These three characteristics all suggest that life may have existed, or currently exists, on Mars.

In addition to the Mars Express Orbiter and the Mars Exploration Rover Mission, the Mars Science Laboratory and Curiosity rover have contributed to our understanding of the Martian environment and the potential for Mars to house life. The Mars Science Laboratory, which carried the Curiosity rover, arrived at the Gale Carter on Mars in 2012. Curiosity then explored the surface of Mars, collecting and analyzing soil and rock in an attempt to find conditions and organic molecules that could support life. Using several instruments, including a laser, hydrogen detector, and spectrometer, Curiosity has analyzed many aspects of the Martian surface. Its laser vaporizes surface samples, with the resulting gasses sent to test chambers on the rover. In these chambers, Curiosity is able to analyze the elemental composition of the material, and identify carbon-containing compounds that indicate the possibility for life. Additionally, the rover investigates whether nitrogen, phosphorus, sulfur, and oxygen are present. Not only does Curiosity analyze the chemical composition of the Martian surface, it also measures the radiation levels of the planet, which determine its habitability. Curiosity has found a former streambed, found rocks containing elements that support life, and found methane emissions as well. Curiosity, therefore, has provided evidence that Mars had sustained life in the past, and may still support microbial life somewhere on the planet.

Spirit, Opportunity, Curiosity, and the Mars Express have all enhanced our understanding of whether Mars can support life, or if it has at least housed life in the past. These missions have all provided valuable information regarding the Martian surface and atmosphere that have furthered our understanding of life on Mars. With these ongoing missions, along with future mission such as the ExoMars program and Mars 2020, our understanding of the potential for other life within our Solar System will continue to grow.

Sources:
http://mars.nasa.gov/programmissions/missions/present/2003/
http://mars.nasa.gov/programmissions/missions/present/express/
http://mars.nasa.gov/programmissions/missions/present/msl/
http://www.space.com/20396-mars-rover-curiosity-big-discoveries.html

- Zac Ettensohn