RocketSTEM Issue #12 - July 2015 | Page 30

Jim Irwin works at the Lunar Roving Vehicle during the first EVA at the Hadley-Apennine landing site. A portion of the Falcon Lunar Module is on the left. The undeployed Laser Ranging Retro Reflector LR-3 lies atop the LM’s Modular Equipment Stowage Assembly MESA. Credit: NASA via Retro Space Images look out there, you see boulders, but you can’t really tell whether it’s a large boulder at a great distance or a small boulder nearby. If it’s very nearby, it’s easy because you can run out along the ground and start calibrating your eyes. If you’re looking close to the LM, you know what three or four inches are, but as you start going out, you start losing your perspective, because there’s nothing to measure out there. It’s a very interesting phenomenon that everybody gets fooled on these distances.” Having said this, Scott added that the tracks of the rover lent some indication of distance. “Once you have some tracks,” he said, “you can start seeing things. As an example, up on the side of Hadley Delta, looking back at the Lunar Module, boy, it was small!” In the absence of an atmosphere or the slightest trace of haze, Falcon appeared far closer and far smaller than it actually was. “But it gives you a scale of how far away it is,” Scott concluded. Even decades later, Scott expressed frustration with his inability to describe how it felt: the ability of his eyes and how well they transmitted images to his brain was good on the Moon. Yet there was nothing on Earth to compare with it. Heading back towards Falcon after a little more than two hours, the two men could take great pride in 28 28 their achievements so far. Yet they still had a sizeable portion of work to do before r