The SSLP is put to an end. Sample analysis are not conclusive.
Density measurement has been gave up at the end of the first week. The accuracy was not good enough
to detect any discrepancy. To have a more accurate measurement of the density, a statistical
protocol could be used. This solution has been though to much time consuming and have not been taken
Color analysis is straightforward. But the samples brought back from the same location do not have
the same color from an operator to another. The soil here is such heterogeneous that between two
samples taken few centimeters away from each other can be very different in color. That make the
color analysis not pertinent for measuring the learning progression of the beginners. This point
should have been anticipated.
The size grain distribution analysis is conducted using an USB microscope and by postprocessing the
picture. It has appeared that in the picture there is not enough sand grains to be representative of
the soil sample. That leads to a bias in the grain size distribution which makes difficult to
interpret the results.
If soil samples should be compared, it is suggested to have very accurate analysis that is not
mainly influenced by a slight difference in a location (like color analysis).
The air measurements (temperature and humidity) inside the helmet have proved that taking soil
sample wearing a spacesuit demands a physical effort. The data collected shows that the temperature
increases of about 2°C (with a maximum of 4°C) while the humidity increases of about 5.5% (with a
maximum of 13%). In spite of the airflow provided by the backpack, such a raise in temperature and
humidity show that the flow rate is not sufficient to renew the air inside the helmet when a
physical effort is done. Consequently, it would be very interesting to have CO2 sensors, because it
is believed that it could be a health issue.
Because of that, emergency removal of the helmet should be considered. Especially if someone has to
run away from a danger for a fairly long distance (rocks falling, polar bear in F-MARS, rescue
another crew member, etc). CO2 level can go through the roof and consequently decrease the ability
of the person inside if not putting him/her in danger of intoxication. In an emergency protocol, I
would not be surprised that removing the helmet should be the first thing to do...
Regarding the sphygomanomaters most of the data have been lost for some reason that remains
unexplained. A malfunction is the most probable explanation so far. On the 12 (3 EVAs x 4 people)
records only half are exploitable.
Still they show that raise in heart beat rate can be expected (which confirm the physical effort). A
raise of 20 pulses per minute can be expected. Some of the records show a drop in pulse rate which
concur with a low raise of helmet temperature and humidity.
About the blood pressure, half of the (exploitable) results show a drop of blood pressure, the rest
show a slight raise. Despite there is no medic in the crew, one hypothesis has been proposed. The
soil sample is conducted kneeling down, when the operator finishes, he/she stands up and then takes
his/her blood pressure. By doing so, orthostatic hypotension could occur which leads to lower blood
pressure, in the arm, than before taking the soil sample.