Combined Spectroscopic Analysis of Terrestrial Analogs from a Simulated Astronaut Mission Using the Laser-Induced Breakdown Spectroscopy (LIBS) Raman Sensor: Implications for Mars.

One of the primary objectives of planetary exploration is the search for signs of life (past, present, or future). Formulating an understanding of the geochemical processes on planetary bodies may allow us to define the precursors for biological processes, thus providing insight into the evolution of past life on Earth and other planets, and perhaps a projection into future biological processes. Several techniques have emerged for detecting biomarker signals on an atomic or molecular level, including laser-induced breakdown spectroscopy (LIBS), Raman spectroscopy, laser-induced fluorescence (LIF) spectroscopy, and attenuated total reflectance Fourier transform infrared (ATR FT-IR) spectroscopy, each of which addresses complementary aspects of the elemental composition, mineralogy, and organic characterization of a sample. However, given the technical challenges inherent to planetary exploration, having a sound understanding of the data provided from these technologies, and how the inferred insights may be used synergistically is critical for mission success. In this work, we present an in-depth characterization of a set of samples collected during a 28-day Mars analog mission conducted by the Austrian Space Forum in the Dhofar region of Oman. The samples were obtained under high-fidelity spaceflight conditions and by considering the geological context of the test site. The specimens were analyzed using the LIBS-Raman sensor, a prototype instrument for future exploration of Mars. We present the elemental quantification of the samples obtained from LIBS using a previously developed linear mixture model and validated using scanning electron microscopy energy dispersive spectroscopy. Moreover, we provide a full mineral characterization obtained using ultraviolet Raman spectroscopy and LIF, which was verified through ATR FT-IR. Lastly, we present possible discrimination of organics in the samples using LIF and time-resolved LIF. Each of these methods yields accurate results, with low errors in their predictive capabilities of LIBS (median relative error ranging from 4.5% to 16.2%), and degree of richness in subsequent inferences to geochemical and potential biochemical processes of the samples. The existence of such methods of inference and our ability to understand the limitations thereof is crucial for future planetary missions, not only to Mars and Moon but also for future exoplanetary exploration.

Laboratory Analysis of Returned Samples from the AMADEE-18 Mars Analog Mission.

Between February 1 and 28, 2018, the Austrian Space Forum, in cooperation with the Oman Astronomical Society and research teams from 25 nations, conducted the AMADEE-18 mission, a human-robotic Mars expedition simulation in the Dhofar region in the Sultanate of Oman. As a part of the AMADEE-18 simulated Mars human exploration mission, the Remote Science Support team performed analyses of the Dhofar area (Oman) in an effort to characterize the region as a potential Mars analog site. The main motivation of this research was to study and register selected samples collected by analog astronauts during the AMADEE-18 mission with laboratory analytical methods and techniques comparable with those that are likely to be used on Mars in the future. The 25 samples representing unconsolidated sediments obtained during the simulated mission were studied by using optical microscopy, Raman spectroscopy, X-ray diffraction, laser-induced breakdown spectroscopy, and laser-induced fluorescence spectroscopy. The principal results show the existence of minerals and alteration processes related to volcanism, hydrothermalism, and weathering. The analogy between the Dhofar region and the Eridana Basin region of Mars is clearly noticeable, particularly as an analog for secondary minerals formed in a hydrothermal seafloor volcanic-sedimentary environment. The synergy between the techniques used in the present work provides a solid basis for the geochemical analyses and organic detection in the context of future human-robotic Mars expeditions. AMADEE-18 has been a prime test bed for geoscientific workflows with astrobiological relevance and has provided valuable insights for future space missions.

The AMADEE-18 Mars Analog Expedition in the Dhofar Region of Oman.

From February 1 to 28, 2018, the Austrian Space Forum, in cooperation with the Oman Astronomical Society and research teams from 25 nations, conducted the AMADEE-18 mission, a human-robotic Mars expedition simulation in the Dhofar region in the Sultanate of Oman. A carefully selected field crew, supported by a Mission Support Center in Innsbruck, Austria, conducted 19 experiments relevant to astrobiology, engineering disciplines, geoscience, operations research, and human factors. This expedition was the 12th in a series of analog missions that emulate selected aspects of the science expected for a human Mars mission, including the characterization of the (paleo)geological environment, human factors studies, and the search for biomarkers. In particular, an Exploration Cascade was deployed as a suggested workflow for coordinating the timing and location of the respective instruments and experiments. In validation of this workflow, the decision-making interaction between the field and the Mission Support Center was studied. This article introduces the AMADEE-18 mission and provides the mission-specific context for the other contributions of this special issue.