Phase II initiates both sampling and methods development for exploring the microbial diversity of the mission area. The broad objectives of this phase are:

1. To sample identified environmental niches likely to harbor specialized organisms, in collaboration with mission geologists
2. To test sampling methods designed to collect microorganisms under Mars analog conditions
3. To test culture methods for growth of selective populations
4. To integrate biology into field engineering operations.

Two days of wet weather prevented some of the planned field work, but we have made progress in several areas.

One type of niche is the upper and lower surfaces of rocks of different compositions. The top surface is clearly subject to wide temperature variation, water availability only during rain and from atmospheric humidity, and high fluxes of visible and ultraviolet light. The bottom surface is more uniformly damp, has no light or UV, and a more stable temperature. During EVA 31, to a location in the general area of White Rock Canyon, two types of igneous rocks were sampled on both the top and bottom surfaces. The sampling method consisted of rubbing sterile cotton swabs over undisturbed surfaces under field sterile conditions. After swabbing vigorously, the end was inserted into a sterile 1.5 ml snap-cap tube. The stem was cut with an alcohol-sterilized surgical scissors, and the cap closed. These operations were performed easily with 3-millimeter dive gloves, as part of the Marskin suit simulation.

In the laboratory, each of the samples was dry-spotted onto both rich and minimal media, and incubated in very dim light at 30°C. No results are available yet. Minimal medium was made with roughly filtered water from Kent Reservoir, collected during EVA 26. The idea here is that local organisms are adapted to survive in this environment, and that local standing water represents runoff from soluble and fine textured minerals. However, there was a significant precipitate present after autoclaving, which may present difficulties. If so, further initial filtration should help with this problem. Sampling methods development will continue during subsequent phases.

A datalogger was available during EVA 26, and was used during sample collection. It is an enormously helpful tool that made it possible to record specific information, such as GPS location, and other comments during sampling at each feature of the site. We look forward to further datalogger development.

A noteworthy feature of the MDRS area is the presence of ground-water sapping leading to the formation of characteristic theater-headed valleys. These are of particular interest since Mars shows similar morphological features, and may represent sites providing suitable niches for any extant life. Such a valley was previously identified during a Phase I scouting mission (EVA 15). We returned during EVA 48 to take biological samples from selectd microhabitats, and to evaluate the physical operations of work at this site. Samples included material from a blue-black deposit, from exfoliationg crust under a significant overhang (Morrison formation), from an ochre-colored thin layer, and from a luxurious mossy coating. Sampling beneath this overhang required standing on steep rubble while reaching overhead, and filling a very small snap-cap tubes under sterile conditions. Other samples under the overhang were obtained for PIMA analysis of mineral content. We also collected samples further down the slope, including conspicuous salmon-orange gypsum and cross-bedded gypum stained green from directly overlying layers.

We are skeptical that any robotic sampler could have obtained these particular samples. The local topography was both steep and complex, and a sampler would need to make complex decisions while balancing on an unstable slope and/or traversing an overhang. Small position changes might well send the robot tumbling down to the valley floor.