INFRARED SPECTRAL STUDIES ON EARTH THAT ADDRESS THREE PRIME ISSUES ON MARS: UNCERTAINTY, UNCERTAINTY, UNCERTAINTY

A primary goal of infrared spectral studies of Mars is to identify the minerals present, and then use that information to derive geologic interpretations. However, in practice, identification of the materials has proven difficult. Often there are changing or contradictory interpretations. That result has led the broader NASA community to desire improved definition of the uncertainties. We will discuss the importance of terrestrial analog studies to understanding the uncertainties, and explain why and how a Mars analog study should differ from a typical terrestrial infrared remote sensing study.

Current questions within the broader Mars research community include (1) Which interpretations of infrared data sets are highly certain, and which are less so? (2) When researchers report that a mineral is not detected, what is the uncertainty, and at what abundance? 10%? 80%? (3) If coatings are common on Mars, then what are orbited instruments commonly mapping?

One method to determine many of the uncertainties is to apply parallel methods on Earth, then check the results. However, most terrestrial remote sensing studies iteratively combine significant ancillary information with airborne or satellite data to map materials. Conversely, we lack hands-on access for Mars. Thus Mars analog research is more complex than simply mimicking a typical terrestrial methodology.

However, one terrestrial remote sensing community does frequently parallel the approach used for Mars: the defense community. That commonality is because the defense community also needs to identify materials both without a person on-site or returned samples. Due to the nature of defense work, that community also places high value on constrained uncertainties, so they require and fund more demanding field tests to develop those constraints.

We will report results of infrared hyperspectral ground and airborne Mars analog studies of two unique sites: (1) Manmade craters at the Nevada Test Site (NTS) and (2) Hot springs at Coso within the China Lake Naval Air Weapons Station, California. The relatively fresh NTS craters and the unusually pristine hot springs at Coso both offer unique test beds for important remote sensing problems for Mars. The results illustrate why appropriate field studies are necessary to answer the three critical questions listed above.