The Red Planet has been an Earthling obsession for the possibility that it may have (at least hypothetically) hosted alien microbes before time immemorial. To potentially answer David Bowie's echoing question about whether there is — or at least ever was — life on Mars, NASA has made an astronomical leap in determining where the Mars 2020 Rover should land.
Mars 2020 (which will eventually have a name like its predecessors) recently had its future debated by scientists at a workshop in Monrovia, California, where its destination was narrowed down to three possible sites. So far, while past rovers have made many tantalizing discoveries that have hinted at possible hotbeds of life billions of years ago, there has never been any hard evidence to support the swarms of theories spawned by volcanic residue and bone-dry rivers. Sites being considered must meet strict geological criteria designed to maximize the chance of unearthing actual evidence that Mars once swarmed with microbes.
"The Mars 2020 mission would explore a site likely to have been habitable, seek signs of past life, fill a returnable cache with the most compelling samples, take the first steps towards onsite resource utilization on Mars, and demonstrate technology needed for the future human and robotic exploration of Mars," explains the workshop website. Even if no fossilized microbes make an appearance, data collected by the rover could prove invaluable to further fleshing out scientists' current understanding of the planet's geological history. High-resolution images and ultra-specific data from NASA's Mars Reconnaissance Orbiter (MRO) were critical in evaluating landing sites.
There may be human missions to Mars by 2030, but for now, while only robotic explorers are making the journey, the candidates the landing are:
Columbia Hills, Gusev Crater
Sound familiar? It would be, because it was previously investigated by NASA's now-silent Spirit Rover back in 2010. The 4-billion-year-old crater is rife with mineral-rich igneous rock from volcanic activity. Minerals preserved in the rocks of the Columbia Hills revealed an aqueous presence, a discovery made by Spirit that led scientists to believe hypothetical hot springs existed and that the Gusev Crater could have once been a shallow lake. While water is never definite proof of a primordial soup of bacteria (however tempting that idea may be), Mars 2020 may uncover even more signs that H2O once existed here.
More distant and less likely than sites for NASA's prior Martian missions, Jezero Crater is thought to have once been a lake that overflowed with water and subsequently dried up at least twice because of its ghostly river channels. Scientists theorize that water remained in the lake long enough for microbial life to take hold. Volcanic activity is also thought to have occurred here. Samples from Mars 2020 will be analyzed for remains of organic matter both on site and in labs back on Earth, with mineral residue additionally providing valuable insight into the ancient atmospheric processes of the Red Planet.
Not far from Jezero Crater is the final contender for Rover 2020's attention, an area where the heat from volcanic activity (inferred from igneous rocks and clay minerals), along with an antediluvian flow of surface water, are believed to have created an environment where the theoretical Martian microbes that continue to elude us potentially flourished. Scientists believe it is an area that could've been crawling with the chemical reactions necessary for life to emerge.
So how does Mars 2020 compare to Curiosity? Both look like futuristic ATVs made for navigating extraterrestrial terrain. The upcoming rover will also land via sky crane and be energized by a Radioisotope Thermoelectric Generator (RTG) that runs on plutonium. Mars 2020 surpasses its predecessor with technology that will make it easier to determine its exact landing spot. With a quest fueled by the question of whether life really existed on the Red Planet, it will also be equipped with 40 tubes to collect a cache of material from the Martian surface.
Whether or not hard evidence of life on Mars ever materializes, watch for blast-off in July 2020.
(via Sky and Telescope)