Trail of Discovery at Fra Mauru
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Trail of Discovery at Fra Mauru

November 27, 2012
A month has already passed since LROC acquired its first images of the Apollo landing sites. In this time the Moon completed one rotation beneath LRO’s orbit, thus providing another set of overflights. Because LRO is not in synch with the lunar day we see the same ground with different lighting – this time the Sun is 24 degrees higher above the horizon providing a clearer view with fewer shadows. Albedo contrasts are greater, and more clearly show soil disturbances from landing, astronaut surface operations, and blast off. Apollo 14 Astronauts Alan Shepard and Edgar Mitchell explored the Fra Mauro highlands, which are composed of ejecta from the massive Imbrium impact. During two lunar surface extravehicular activities, Shepard and Mitchell deployed an Apollo Lunar Surface Experiments Package ALSEP, tested the Modular Equipment Transporter (MET; a small wheeled cart used to transport samples and equipment), and collected almost 90 kg of invaluable lunar rock and soil. The ALSEP is visible about 180 meters west of the lunar module, note the well worn footpath connecting the two artifacts. During the second EVA, the astronauts performed what is known as a “radial traverse” across the ejecta field and up to the rim of Cone crater. When impact craters form, rocks excavated from the deepest parts of the crater fall near the rim; surface rocks end up away from the crater. Thus, as explorers move up a crater's ejecta blanket, they can sample a complete stratigraphic section of geologic materials providing priceless insights about the composition and nature of the lunar subsurface. Think of an impact crater as a natural roadcut exposing rocks from depth. In this LROC image, you can follow nearly the whole path walked by the two astronauts. The term “radial traverse” does not quite do the crew of Apollo 14 justice. Their journey sounds like a stroll in the park, however the reality is quite the contrary. The hike up Cone crater was quite challenging. For the first time, astronauts traveled out of the sight of their lunar module while hiking uphill over 1400 meters with only a poor map, dragging the tool cart (MET), and wearing their bulky spacesuits. It was an amazing feat that the two astronauts made it to the top of Cone ridge and acquired all their samples. They ended up about 30 meters shy of peering into Cone crater itself, surely a disappointment at the time, but absolutely no reflection on the success of the traverse and the scientific results gleaned after the mission. Annotated figure showing the positions of various landmarks surrounding the Apollo 14 landing site. The small white arrows highlight locations where the astronauts' path can be clearly seen. Credit: NASA/GSFC/Arizona State University

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