Use of an Aerial Vehicle for Exploration in a Mars Analog Environment
Authors: Stacy T. Sklar, Mike Turner & Shannon M. Rupert

Overview:

Aerial vehicles have long been discussed in Mars exploration strategies because of their extended range and capability to provide detailed information from a perspective unique to flight. The Mars Desert Research Station (MDRS) in Utah provides an excellent opportunity to test such a vehicle in a Mars analog environment under simulation conditions and in terrain that resembles what we have found on Mars. We propose to evaluate the usefulness of an unmanned aircraft in a Mars analog environment by using a remote controlled aerial vehicle, dubbed an ARV (Aerial Reconnaissance Vehicle), to look for possible sites of scientific interest. These sites will first be identified using aerial imagery and then investigated further by ground truthing.

Design & Operation of the ARV:

There were three main goals to be met in the design of the ARV: aerodynamics, safety and imaging. We needed to be able to map features of scientific interest safely and effectively. We also acknowledged that if the ARV were lost, the aerial imaging mission would be invalidated, so a stable, durable aircraft was required. Also, in order to image features effectively, the ARV needed to be able to fly at relatively low speeds. The final choice for the ARV was a PT-60 trainer aircraft, which is more stable than a RC aircraft and has better survivability in crashes. In addition, the flight speed was conducive to our goals, since the lower speed limit for this craft is 40 kph.

Our imaging system is an AAR14 video camera with a transmitter receiver system. The camera has one degree of motion during a single flight. However, during refueling, the range of motion can be adjusted to accommodate a different axial range, changing from an aerial view to a stratigraphic view. With a normal flight time of only fifteen minutes, the ARV will require refueling multiple times during an EVA, so we will be able to obtain multiple views each EVA.

The data will be received and recorded in real time. At the end of each day, the video will be examined and analyzed. We will select from the videotape, based on the scientific objectives detailed below, the images we will make into stills for image mapping. The stills will be created by using an extraction software program created by the crew engineers. These images will then be evaluated by the crew scientists and the RST for possible sites of scientific investigation. The goal will be to determine the usefulness of the ARV images in both EVA planning and scientific exploration of sites. (See additional posted documents for more information on the engineering and computer programming aspects of the ARV and its imaging system.)

Project Phases & Goals:

The project will be divided into two phases. In the first phase (engineering/aerial imaging), we will test the operational capabilities of the ARV both in terms of flight and imagery. In the second phase (scientific/ground truthing), we will use the imagery obtained by the ARV to ground truth our interpretation of possible sites of scientific interest in the images.

Priority sites to fly the ARV were selected based on research and experience by both the MDRS Remote Science Team (RST) and the crew scientists. The scientific sites that were selected for ARV imaging include known areas for sapping (Howard, 1988), evaporites, concretions, extremophiles, fluvial activity and documented regolith mapping (Clarke, 2004). The areas selected from within the USGS Factory Butte 7.5 Quadrangle Topographical Map include Caineville Mesa (Sumerville Formation), Factory Butte (Mancos Shale), Factory Bench (Dakota Formation) and the area surrounding MDRS (Morrison Formation), which is also located within the USGS Skyline Rim 7.5 Quadrangle Topographical Map.

During phase one of the mission (week one of the rotation), the ARV testing will be done out of simulation conditions (sim) for the first two days or until the pilots feel comfortable flying the vehicle. As part of the training for the mission, three sites have been selected to test the vehicles capabilities. While these sites are not part of the mission objectives the training EVAs are intended to gradually increase the crews ability of piloting the ARV onto more difficult flight paths. During these early EVAs the ARV will first fly over sites to map regolith, outflow pipes, and fluvial activity, and will increase in flight complexity to include stratigraphy. We will then go into sim for the remainder of the week. However, if these training flights demonstrate that flying in sim will be a hazard to either the crew or the ARV, we will conduct EVAs in partial sim by having two of the crew out of sim to maintain safety. This is consistent with the guidelines of a sim, where safety has the highest priority.

There are two ways to deploy and operate a robotic, unmanned field assistant like the ARV. The first is to use the ARV as a "buddy" and have it integrated as part of an astronaut EVA. In this scenario, the ARV would be operated by one or more of the EVA team, while field exploration and investigation on the ground was being conducted simultaneously. In the second scenario, the ARV is used as a scout. Prior to an astronaut going into an unknown area, the ARV is remotely directed to an area which will be explored by the scientists at a later date. The information returned by the ARV is analyzed and used by the crew for EVA planning. The phase one ARV flights will utilize the ARV as a scout. The only field data collected by the EVA crew during flights will be location (GPS), since the ARV does not have that capability. All location coordinates will be collected using NAD 27.

During the second phase (week two of this rotation and the first time there will be an all female crew at MDRS) we will revisit the same sites imaged by the ARV in order to further investigate the usefulness of the ARV as a scientific tool. We will ground truth selected sites using our analysis of the video and stills as a starting point for our geological and biological investigations. Emphasis will be placed on locating extremophile niches (particularly endoliths and halophiles), concretions, sapping sites and desert varnish. We will also investigate a possible muddy roll up. Priority of sites will be determined after testing of the ARVs capabilities for imagine. Scientific priorities will be concretion and endolithic sites.

Extremophiles & Evaporites:

Extremophiles are microorganisms that live in extreme environments. Two common extremophiles in the area around MDRS are endoliths and halophiles, although a variety of extremophiles exist at Mars analog sites worldwide. Halophiles are microorganisms that live in environments with high salt concentrations. They are found in areas where evaporites, residue of salts (including gypsum and some more soluble species including sodium chloride) that have precipitated by evaporation, can be found. Evaporite deposits can be identified in aerial images by a telltale "bathtub ring" that surrounds the ancient basin when the evaporation occurred and by depositions of white regolith. We will look for evidence of these "bathtub rings" as sites to ground truth possible evaporite and halophile sites.

Endoliths are ubiquitous at MDRS and can often by identified over far distances by the greenish tinge they produce in the rocks where they live. We will examine the aerial photos for this greenish tint and use that as an indictor of possibly endolith sites. We recognize that entholithic communities may not be exposed and so will also focus our study on sandstone and conglomerate units within depositional fluvial activity, such as is found at the Hab Ridge Martian Squeeze.

Our ground truthing will focus on sample collection within the different members of the Dakota Formation and mapping (lateral and stratigraphic) and verification of depositional environments and facies where these organisms occur. . In addition, we will be investigating sites first examined by Battler in 2004 to determine diagenetic controls on Units 1 - 5, as identified by Battler's Stratigraphic Column (See Figure below). It is the author's hypothesis that the diagenetic process within these units is similar not only to the Navajo concretion sites but also to Mars concretion sites as well and that due to the diagenetic process extremophiles may occur on Mars within these diagenetic sites such as Merediani Plannum.

We will document and analyze the niches of extremophiles and perform basic biological analysis of collected samples. Suspected halophiles will be collected and cultured by Vuong Nguyen of Miramar College. Suspected endoliths will be confirmed through microscopic analysis. In addition, at each site that is identified or suspected to contain extremophiles, we will complete extensive photo documentation (including ARV images, if applicable), basic geological analysis (including hand sample analysis and light microscopy). Further microscopic analysis of collected samples, including SEM, will be completed at our home institutions.

Concretions:

Concretions are round mineral masses found in sedimentary rocks and are of significant interest at MDRS since their analog was found on Mars. We will compare aerial images we take of known concretion sites at MDRS to other images in an attempt to locate additional sites. Our investigational focus will include a comparison of Mars and Navajo concretions sites (Chan, 2004), creation of a map of the lateral extent of known sites, determining density and distribution and comparing concretion host rock sites to endolith host rock sites.

Desert Varnish:

Desert varnish is a thin, blackish coating of manganese, iron and clays found on sun-baked rocks which has been precipitated by bacteria over thousands of years. These bacteria oxidize the manganese and iron, rather than glucose, to generate ATP. Desert varnish is often associated with desert pavement, an alluvial feature in arid climates. Desert varnish is called gibber plains in Australia, so studies done here could be repeated at MARS-OZ. Desert varnish is common in Australia but has not been extensively studied. There it is generally quite thin and best developed on siliceous rocks (Clarke, 2005). We will use the association of desert varnish with desert pavement, visible from the air, to identify possible desert varnish sites with the ARV imagery. Any sites discovered through ground truthing will be documented and these data forwarded to Dr.Penelope Boston.

Muddy Roll-Up:

A possible microbial muddy roll-up was discovered at MDRS. We will return to the site and further investigate by taking measurements of and photodocumenting this muddy roll-up structure. We will also map (lateral and stratigraphic) and verify the depositional environments and facies.

RST Involvement:

Once ARV imagery has been analyses, images will be sent to the RST for review. We will rely on the involvement of the RST for confirmation of possible sites, keeping us aware of anything that we may have overlooked, review of our science reports for errors and omissions and for evaluation of our communication of scientific data and analysis.

One possible future project that the RST could undertake is to continue analysis of ARV imagery and directing crews in ground truthing those analyses.

Products:

The results of this study will be presented at the Mars Society Conference in August 2005. The identified sites will be put into a geology database currently under development by the RST.

References:

Battler, Melissa, "Paleoenvironmental Interpretation of the Dakota Sandstone Formation as an Analog for Mars", unpublished senior thesis (2004), University of Waterloo, Waterloo, Ontario

Chan, Marjorie A; Beitler, Brenda; Parry, W T; Ormo, Jens; Komatsu, Goro, "A possible terrestrial analogue for haematite concretions on Mars," Nature (London), vol.429, no.6993, pp.731-734, 17 Jun 2004

Clarke, Jonathan; Pain, Colin F; (2003) Martian Expedition Planning. In C.S. Cockell (Ed.), The Martian Expedition Planning Symposium of the British Interplanetary Society: Vol. 107. "From Utah to Mars: Regolith--Landform Mapping and its Application" pp 131-159, San Diego, CA: American Astronautical Society and the British Interplanetary Society

Clarke, Jonathan. Personal communication. 2005

Howard, Alan D; Kochel, Craig R; Sapping features of the Colorado Plateau; a comparative planetary geology field guide. In Howard, Alan D; Kochel, Craig R; Holt, Henry E (Ed.), "Introduction to Cuesta Landforms and Sapping Processes on the Colorado Plateau", NASA Special Publication, vol.491, pp.6-56, 1988