Remote sensing of chiral signatures on Mars

We describe circular polarization as a remote sensing diagnostic of chiral signatures which may be applied to Mars. The remarkable phenomenon of homochirality provides a unique biosignature which can be amenable to remote sensing through circular polarization spectroscopy. The natural tendency of microbes to congregate in close knit communities would be beneficial for such a survey. Observations of selected areas of the Mars surface could reveal chiral signatures and hence explore the possibility of extant or preserved biological material. We describe a new instrumental technique that may enable observations of this form.

► Microbial photosynthesis may have arisen on early Mars and signatures could persist. ► Homochirality is a strong biosignature detectable remotely in circular polarization. ► Highly localized chiral material is normal on Earth, which enhances detectability. ► A robust new instrumentation method may enable observations at Mars.