january 24, 2014, nasa reported that current studies by the curiosity and opportunity rovers on mars will now be searching for evidence of ancient life, including a biosphere based on autotrophic, chemotrophic and/or chemolithoautotrophic microorganisms, as well as ancient water, including fluvio-lacustrine environments (plains related to ancient rivers or lakes) that may have been habitable. the search for evidence of habitability, taphonomy (related to fossils), and organic carbon on the planet mars is now a primary nasa objective.