Context: Biology EVA #2 on ATV to Tank Wash off Lowell Highway. The approximate GPS coordinates of the location were 12S 0517967E 4254071N.

Summary of Field Work: Amy, Ryan, Kevin followed directions as outlined by RST and traveled 5.5 km to Tank Wash, just off Lowell Highway. The crew took the three required identifying photos of the wash, one extra photo at the entrance to the wash, and four photos from north, south, east, and west at the middle of the sampling location. We then collected 18 samples (10 dry, 8 wet) at various sites within the wash and noted the time, soil temperature, UV exposure, surrounding geology and wet/dry status. This data was sent to RST in an Excel data sheet.

Sampling Location Physical Description: The sampling was done in a wash just off the highway, framed by an eroded rock structure. It included many waterways, small and large, as well as an island in the middle and rocky slopes surrounding the wash. Samples were taken mainly from the island and the waterways, as the slopes were too rocky to take large enough samples.

Photos Taken: (Click Image for Detailed View)
Entrance to the wash, facing east.	Entrance to the wash, facing north.
Highest point near the wash, looking northeast.	Inside the wash, looking back towards the road.
Sampling location facing north.	Sampling location, facing south.
Sampling location, facing east.	Sampling location, facing west.

CO₂ Experimentation Status: Samples were prepared for the RST with 10 grams from each site. The remainder of each sample was left in the sampling container original sampling container to be tested in the Hab for microbial richness. The mass of the samples was recorded at this point. Then two mL of water was added to each sample and stirred in with a clean toothpick. Vials of soda lime (approximately 4 grams each – the exact mass was noted) were prepared and placed, uncapped, into the sampling containers. The mass measurements were included in the Excel data table set to RST. The sampling containers were then resealed. Due to the need to conserve power until the new generator is running, these samples were not placed in the incubator. Instead, they were left on the lab table in the Hab. The samples from March 3 were left in the incubator, which was turned off. On March 9, the samples from EVA 5 will be removed from the incubator and the masses of sample and soda lime will be re-measured. On March 10, the same will be done for today's samples.

Difficulties Encountered and Lessons Learned:

• In this EVA, taking large enough samples was much easier. Most samples were large enough to save over 40 grams for CO2 testing. However, some samples were still not large enough. In future Biology EVAs, the sampling containers will be filled at least halfway to ensure that the sample is large enough.
  
  
• Taking samples from wet ground can be almost as difficult as sampling from rocky ground. In this case, getting the core sampler into the ground is no problem, but getting the sample out of the sampler and into the container is very difficult. Having one person hold the sample container and the other hold the sampler and a scoopula is often the best method.
  
  
• When taking samples in wet areas, watch out for mud.
  
  
• After taking samples in wet locations, the soil corer is very difficult to clean out. We have been using a wire brush, which is far from ideal for this purpose. Often the wire brush is dirtier than the corer it is supposed to be cleaning. We are still looking for an alternate cleaning method.
  
  
• Scoopulas get muddy as much as the soil core sampler and are just as difficult to clean. Instead of spending a lot of time cleaning them in the field, multiple scoopulas could be used and cleaned later in the lab.
  
  
• Thermistors are fragile. They bend easily upon hitting hard ground or rock, so care should be taken not to push too hard. In soft ground, problems can still arise if the metal part of the thermistor gets stuck, as it did today. In this case, do not wiggle or twist the thermistor to loosen it. Instead, be sure to have something on hand to dig it out after the sample is taken nearby. Also, carry an extra thermistor in case the first one breaks anyway.