21st-Century Astrobiology Missions Should Seek These High-Confidence Biosignatures

This white paper was submitted to NASA's Search For Life Science Analysis Group (SFL-SAG): To ensure that the first mission designed to seek signs of extant life since 1976 is able to produce an unambiguous biological interpretation, the SFL-SAG is tasked with identifying the most high-confidence, agnostic biosignatures which are targetable, detectable, and measurable in Martian subsurface mid-latitude ice. To aid in this effort, this white paper highlights three examples of target materials or phenomena, along with associated instrument concepts, which the SFL-SAG shall prioritize in its efforts to define the appropriate astrobiological strategy. These include 1) polyelectrolyte informational biopolymers, 2) macromolecular biological homochirality, and 3) chiral-specific metabolic reactions. The Agnostic Life Finding Association (ALFA) and University of Florida (UF) support the development of instrumentation that seeks these high-confidence biosignatures.