This Feature introduces and discusses the findings of key analytical techniques used to study planetary bodies in our solar system in the search for life beyond Earth, future missions planned for high-priority astrobiology targets in our solar system, and the challenges we face in performing these investigations.

One of the greatest and most long-lived scientific pursuits of humankind has been to discover and study the planetary objects comprising our solar system. Information gained from solar system observations, via both remote sensing and in situ measurements, is inherently constrained by the analytical (often chemical) techniques we employ in these endeavors. The past 50 years of planetary science missions have resulted in immense discoveries within and beyond our solar system, enabled by state-of-the-art analytical chemical instrument suites on board these missions. In this review, we highlight and discuss some of the most impactful analytical chemical instruments flown on planetary science missions within the last 20 years, including analytical techniques ranging from remote spectroscopy to in situ chemical separations. We first highlight mission-based remote and in situ spectroscopic techniques, followed by in situ separation and mass spectrometry analyses. The results of these investigations are discussed, and their implications examined, from worlds as close as Venus and familiar as Mars to as far away and exotic as Titan. Instruments currently in development for planetary science missions in the near future are also discussed, as are the promises their capabilities bring. Analytical chemistry is critical to understanding what lies beyond Earth in our solar system, and this review seeks to highlight how questions, analytical tools, and answers have intersected over the past 20 years and their implications for the near future. Expected final online publication date for the Annual Review of Analytical Chemistry Volume 15 is June 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Capillary electrophoresis is a powerful separation tool with a wide range of analytes for diverse applications and is compatible with various detection methods. While some more established separation techniques like gas or liquid chromatography are utilized heavily in analytical chemistry laboratory courses, newer commercial capillary electrophoresis instrumentation remains underrepresented in undergraduate laboratories, with the concepts being largely in the realm of lecture alone in analytical chemistry curricula. Despite its proven power and wide application, an undergraduate laboratory experiment utilizing capillary electrophoresis with laser-induced fluorescence detection (CE-LIF) has yet to be published. Here, we present an experiment for third-and fourthyear undergraduate analytical chemistry courses in which the students use CE-LIF to optimize system parameters, analyze the amino acid profile of a mock "patient sample", and use calibration standards coupled with statistical analysis to provide a phenylketonuria (PKU) diagnosis. This experiment is easily adaptable to a dry lab, making this technique available to laboratories without the resources needed to acquire a CE-LIF system. We also demonstrate that the dry lab analysis can be accomplished in an online format, requiring no student presence in the laboratory, which is especially relevant due to recent events concerning the COVID-19 pandemic.

The Saturnian moon Enceladus presents a unique opportunity to sample the contents of a subsurface liquid water ocean in situ via the continuous plume formed over its south polar terrain using a multi-flyby mission architecture. Previous analyses of the plume’s composition by Cassini revealed an energy-rich system laden with salts and organic compounds, representing an environment containing most of the ingredients for life as we know it. Following in the footsteps of the Cassini-Huygens mission, we present Astrobiology eXploration at Enceladus (AXE), a New Frontiers class Enceladus mission concept study carried out during the 2021 NASA Planetary Science Summer School program at the Jet Propulsion Laboratory, California Institute of Technology. We demonstrate that a scientifically compelling geophysical and life-detection mission to Enceladus can be carried out within the constraints of a New Frontiers-5 cost cap using a modest instrument suite, requiring only a narrow angle, high-resolution telescopic imager, a mass spectrometer, and a high-gain antenna for radio communications and gravity science measurements. Using a multi-flyby mission architecture, AXE would evaluate the habitability and potential for life at Enceladus through a synergistic combination of in situ chemical analysis measurements aimed at directly detecting the presence of molecular biosignatures, along with geophysical and geomorphological investigations to contextualize chemical biosignatures and further evaluate the habitability of Enceladus over geologic time.

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