Today (02 Dec 2014) we did measurements for the soil moisture project on two sites during a 2 hour 30 minute EVA. Please see the EVA report for the coordinates. Three members of the Crew 144 took part into the EVA: Commander Gregory Leonard, Crew Engineer Victor Luo, and Crew Scientist Juho Vehviläinen.
The purpose of this particular project is to study soil moisture (and possibly soil frost), its variation and dynamics in time and also spatially. Additionally, the procedures and techniques for the
MA635 mission in the Canadian high arctic are tested in context of Mars simulation. The questions regarding the feasibility in Mars simulation are: 1st can we operate the scientific equipment and 2nd can we do enough measurements during the EVAs. The study sites chosen for the research are on different land cover types from which two are chosen. Namely these are “Barren” and “Shrub”.
Measuring soil moisture and soil frost is an important part of the water balance of Earth as well as an important measure for agriculture and flood protection, just to name a few. As for the future Mars missions, the search for water will be one of the most important tasks. Since there is no free water on surface of Mars, although new research might prove this wrong, the best sources of water will be Martian soil and the polar ice caps.
Problem in studying the soil moisture is that it is highly variable depending on land cover type, topography, height of ground water, meteorological conditions etc. To tackle this we need a large number of measurements to catch the bounds in which the soil moisture varies and to find out the representative locations e.g. for long term monitoring.
As mentioned earlier, today we had two sites to visit. The first site was on land cover type consisting shrubs. Around here the shrubs are widely spaced and dry, since the winter is approaching and there has not been much precipitation. On the shrub site we did 360 meters long transect in West to East direction on
10-30 meter intervals to find out how much the soil moisture varies in larger scale. Well, in these conditions it did not vary that much. Today at the shrub site we measured soil moisture readings ranging from 2 to 9 %. It means that there is 2 to 9 % of water in a certain volume of a certain soil sample.
On the second site, classified as barren, we did a second transect.
The site is approximately 350 meters from the hab. The length of the transect was around 200 meters (SE to NW), and it was done also with 10-30 meter intervals. Here the soil moisture varied more, since there were dried up streams. On these streambeds the soil moisture was almost 20% in depth of
10 cm, but just 3% on drier land between the streambeds.
One of the main findings was that the hardness of the soil surface varies considerably from rock hard to kind of small grain beach sand. This means that the measurements could not be done on the certain locations.
The next steps for the soil moisture project depend on the weather. If the prevailing weather changes, we will do the same transects again to see how the soil moisture will change. If the weather does not change, we will investigate additional sites and do shallow vertical profiles to depth of 30-40 cm.