Mars-Relevant Field Experiences in Morocco: The Importance of Spatial Scales and Subsurface Exploration.

During field work at the Ibn Battuta Mars analogue sites, two research questions were analyzed: (1) How do we identify sampling sites using remote and local imaging and (2) what kind of information can be gained from shallow subsurface exploration? While remote images help in targeting field activities in general, the connection between observations at different spatial scales for different rocky desert terrain types is not well established; in this, focused comparison of remote in situ images of well-selected analogues would help a great deal. Dried up lake beds as discerned in remotely acquired data may not show signatures of past water activity, while shallow subsurface exploration could reveal the lacustrine period. Acquisition of several satellite images of the same terrain under different geometries would help to support the planning of such in situ work. The selection of appropriate sampling sites in fluvial settings could be improved by analyzing long, meter-high, open-air outcrops that formed during most recent fluvial episodes. Such settings are abundant on Earth and could be present on Mars but may be just below the resolution of available data. By using 20-30-cm-deep excavations, shallow subsurface exploration could reveal the last period of geological history that would have been unattainable by surface observation alone. Aggregates embedded in the original strata or from heavily pulverized samples could not be identified; only weakly fragmented samples viewed right after acquisition showed aggregates, and thus, the Close-Up Imager (CLUPI) on the ExoMover might provide information on cementation-related aggregation on the observing plate before crushing. The mechanical separation of different size grains (mainly clays and attached minerals) would also support the identification of individual components. To maximize context information during subsurface exploration, rover imaging should be accomplished before crushing; however, currently planned imaging may not be ideal for this.

In Situ Sampling of Relative Dust Devil Particle Loads and Their Vertical Grain Size Distributions.

During a field campaign in the Sahara Desert in southern Morocco, spring 2012, we sampled the vertical grain size distribution of two active dust devils that exhibited different dimensions and intensities. With these in situ samples of grains in the vortices, it was possible to derive detailed vertical grain size distributions and measurements of the lifted relative particle load. Measurements of the two dust devils show that the majority of all lifted particles were only lifted within the first meter (∼46.5% and ∼61% of all particles; ∼76.5 wt % and ∼89 wt % of the relative particle load). Furthermore, ∼69% and ∼82% of all lifted sand grains occurred in the first meter of the dust devils, indicating the occurrence of "sand skirts." Both sampled dust devils were relatively small (∼15 m and ∼4-5 m in diameter) compared to dust devils in surrounding regions; nevertheless, measurements show that ∼58.5% to 73.5% of all lifted particles were small enough to go into suspension (<31 µm, depending on the used grain size classification). This relatively high amount represents only ∼0.05 to 0.15 wt % of the lifted particle load. Larger dust devils probably entrain larger amounts of fine-grained material into the atmosphere, which can have an influence on the climate. Furthermore, our results indicate that the composition of the surface, on which the dust devils evolved, also had an influence on the particle load composition of the dust devil vortices. The internal particle load structure of both sampled dust devils was comparable related to their vertical grain size distribution and relative particle load, although both dust devils differed in their dimensions and intensities. A general trend of decreasing grain sizes with height was also detected.

The MARS2013 Mars analog mission.

We report on the MARS2013 mission, a 4-week Mars analog field test in the northern Sahara. Nineteen experiments were conducted by a field crew in Morocco under simulated martian surface exploration conditions, supervised by a Mission Support Center in Innsbruck, Austria. A Remote Science Support team analyzed field data in near real time, providing planning input for the management of a complex system of field assets; two advanced space suit simulators, four robotic vehicles, an emergency shelter, and a stationary sensor platform in a realistic work flow were coordinated by a Flight Control Team. A dedicated flight planning group, external control centers for rover tele-operations, and a biomedical monitoring team supported the field operations. A 10 min satellite communication delay and other limitations pertinent to human planetary surface activities were introduced. The fields of research for the experiments were geology, human factors, astrobiology, robotics, tele-science, exploration, and operations research. This paper provides an overview of the geological context and environmental conditions of the test site and the mission architecture, in particular the communication infrastructure emulating the signal travel time between Earth and Mars. We report on the operational work flows and the experiments conducted, including a deployable shelter prototype for multiple-day extravehicular activities and contingency situations.

Field trial of a dual-wavelength fluorescent emission (L.I.F.E.) instrument and the Magma White rover during the MARS2013 Mars analog mission.

Abstract We have developed a portable dual-wavelength laser fluorescence spectrometer as part of a multi-instrument optical probe to characterize mineral, organic, and microbial species in extreme environments. Operating at 405 and 532 nm, the instrument was originally designed for use by human explorers to produce a laser-induced fluorescence emission (L.I.F.E.) spectral database of the mineral and organic molecules found in the microbial communities of Earth's cryosphere. Recently, our team had the opportunity to explore the strengths and limitations of the instrument when it was deployed on a remote-controlled Mars analog rover. In February 2013, the instrument was deployed on board the Magma White rover platform during the MARS2013 Mars analog field mission in the Kess Kess formation near Erfoud, Morocco. During these tests, we followed tele-science work flows pertinent to Mars surface missions in a simulated spaceflight environment. We report on the L.I.F.E. instrument setup, data processing, and performance during field trials. A pilot postmission laboratory analysis determined that rock samples acquired during the field mission exhibited a fluorescence signal from the Sun-exposed side characteristic of chlorophyll a following excitation at 405 nm. A weak fluorescence response to excitation at 532 nm may have originated from another microbial photosynthetic pigment, phycoerythrin, but final assignment awaits development of a comprehensive database of mineral and organic fluorescence spectra. No chlorophyll fluorescence signal was detected from the shaded underside of the samples.

A case for using ground-based thermal inertia measurements to detect Martian caves.

Martian caves are regarded as one of the most interesting locations in which to search for life on the planet. Data obtained during the MARS2013 expedition at Hamar Laghdad Ridge in the Tafilalt region of Morocco indicate that even small cavities can display thermal behavior that is characteristic for caves. For example, temperature in a cavity equaled 14°C±0.1°C before sunrise, which was higher than the temperature of the ambient air (10°C±0.1°C) and proximate rocks (9°C±0.1°C) at the same time. Within 30 min after sunrise, when the temperature of surrounding rocks corresponded to 15°C, this thermal relationship reversed. Measurements were conducted under simulated spaceflight conditions, including near-real-time interpretation of data that were acquired in a complex flight planning environment. We conclude that using ground-based thermal contrast measurements, in 7-14 µm band before and after sunset, is an effective method for Mars astronauts to identify caves, possibly superior to usage of space-based or ground-penetrating data.