Visualizing the Search for Life on Mars with PIXLISE

A generational shift in the magnitude of astrobiology data challenges the prime objective of the Perseverance Mars rover, to collect potential evidence of alien life, or biosignatures, for eventual return to Earth. Previous generations of X-ray fluorescence (XRF) spectrometers acquired one to six spectra per experiment, and required almost three to four weeks to return baseline analyses. The Planetary Instrument for X-ray Lithochemistry (PIXL), mounted on the arm of Perseverance, will return more than 6,000 spectra per experiment. To influence mission sampling decisions, PIXL experiments will have to turn around baseline analyses in just one day, with three orders of magnitude more data. To help address this problem, over seven years, we partnered with the PIXL instrument team at the NASA Jet Propulsion Laboratory. This paper presents a design study of PIXLISE, a visual analytics application for spectroscopy and astrobiology analysis. Deployed over five years in the wild to the PIXL instrument team, and with over a thousand hours of summative evaluation, we describe the impact of PIXLISE on PIXL instrument team. We find that PIXLISE accelerates PIXL experiments fast enough to inform sampling decisions. It achieves this objective by radically breaking down disciplinary silos to scientific collaboration, and by finding a novel signal in what was thought to be instrument anomalies. Together these capabilities enabled PIXLISE to make key contributions to discoveries that made the cover of AAAS Science.