Life on Mars in the context of ExoMars

A biosignature (sometimes called chemical fossil or molecular fossil) is any substance – such as an element, isotope, molecule, or phenomenon – that provides scientific evidence of past or present life on a planet or moon. Measurable attributes of life include its physical or chemical structures, its use of free energy, and the production of biomass and wastes.

The field of astrobiology uses biosignatures as evidence for the search for past or present extraterrestrial life. Candidate biosignatures strongly indicate some of the earliest known life forms, aid studies of the origin of life on Earth as well as the possibility of life on Mars, Venus and elsewhere in the universe.

Mars 2020 is a NASA mission that includes the rover Perseverance, the now-grounded small robotic helicopter Ingenuity, and associated delivery systems, as part of the Mars Exploration Program. Mars 2020 was launched on an Atlas V rocket at 11:50:01 UTC on July 30, 2020, and landed in the Martian crater Jezero on February 18, 2021, with confirmation received at 20:55 UTC. On March 5, 2021, NASA named the landing site Octavia E. Butler Landing. As of 12 December 2025, Perseverance has been on Mars for 1711 sols (1758 total days; 4 years, 297 days). Ingenuity operated on Mars for 1042 sols (1071 total days; 2 years, 341 days) before sustaining serious damage to its rotor blades, possibly all four, causing NASA to retire the craft on January 25, 2024.

Perseverance is investigating an astrobiologically relevant ancient environment on Mars for its surface geological processes and history, and assessing its past habitability, the possibility of past life on Mars, and the potential for preservation of biosignatures within accessible geological materials. It will cache sample containers along its route for retrieval by a potential future Mars sample-return mission. The Mars 2020 mission was announced by NASA in December 2012 at the fall meeting of the American Geophysical Union in San Francisco. Perseverance's design is derived from the rover Curiosity, and it uses many components already fabricated and tested in addition to new scientific instruments and a core drill. The rover also employs nineteen cameras and two microphones, allowing for the audio recording of the Martian environment. On April 30, 2021, Perseverance became the first spacecraft to hear and record another spacecraft, the Ingenuity helicopter, on another planet.

Mars, the fourth planet from the Sun, has appeared as a setting in works of fiction since at least the mid-1600s. Trends in the planet's portrayal have largely been influenced by advances in planetary science. It became the most popular celestial object in fiction in the late 1800s, when it became clear that there was no life on the Moon. The predominant genre depicting Mars at the time was utopian fiction. Around the same time, the mistaken belief that there are canals on Mars emerged and made its way into fiction, popularized by Percival Lowell's speculations of an ancient civilization having constructed them. The War of the Worlds, H. G. Wells's novel about an alien invasion of Earth by sinister Martians, was published in 1897 and went on to have a major influence on the science fiction genre.

Life on Mars appeared frequently in fiction throughout the first half of the 1900s. Apart from enlightened as in the utopian works from the turn of the century, or evil as in the works inspired by Wells, intelligent and human-like Martians began to be depicted as decadent, a portrayal that was popularized by Edgar Rice Burroughs in the Barsoom series and adopted by Leigh Brackett among others. More exotic lifeforms appeared in stories like Stanley G. Weinbaum's "A Martian Odyssey".