Communication and Navigation (Jan): The EVA today used 2 meter voice and APRS; both worked as expected and positioning data was fed to the Internet again.

Human Factors (Jan): The participants keep taking MASCOT and MOODY tests.

Radiation (Jason): Today's EVA allowed the radiation shielding data to be augmented in two ways: both two-layer sand bag and natural rock formation shielding. Since the time of day was different than the 3/25 EVA, a calibration period of radiation measurements was taken before each period of shielded measurements. Approximately 10-15 minute intervals of calibration and shielding were recorded with the Gamma Scout and forthcoming analysis should determine the efficacy of in-Situ resources for radiation shielding.

Two more sand bags were added to the corners of the 3/25 sand bag structure so that a nearly uniform depth (~10") exists for nearly all of the 360° around the two-layer enclosed Gamma Scout. Radiation data was taken between 1254 MST and 1318 MST with the detector inside the sand bag structure after a calibration period from 1241 MST to 1254 MST. The additional sand bags were added as they were created at 4-5 minute; these intervals will be noted in the data spreadsheets sent to Mission Support.

The natural rock formation shielding is a test that has added interest because no human labor is required. A calibration period of 10 minutes was used to get radiation measurements within ~10 feet of the shielding site. The Gamma Scout was then exposed to a subsequent period of 15 minutes inside a sheltered crag in the landscape. Since exact measurements of the shielding thickness were unattainable, a photograph was taken of the shielding arrangements as well as a picture of the scenery in each direction (towards the Henry Mountains, and away) so that the same location can be found again; the GPS was unavailable to take a way point, but the location is within ~20 yards of the sand bag site, from which GPS data exists. With the Henry Mountains to one's right, the Gamma Scout was covered on the top by ~ 5-6 inches of rock with a thin layer of sand above, the entire rock and sand landscape to the left, front and back, with an approximately 3-4" opening between the rocks to the right that allowed the detector to be placed inside.

In addition to the radiation shielding data, the necessary data to create a radiation map of the route was recorded on both the GPS and the Gamma Scout. Even though this is the same route as the 3/25 EVA, a comparison between the data would reveal the variation in radiation over the course of the afternoon since the 3/25 EVA took place in the late afternoon whereas today's occurred near noontime. The remaining radiation reports will analyze and hopefully draw conclusions from the data collected today, referring predominantly to the 3/25 EVA.

Jenny Rome
MDRS Crew 47