RocketSTEM Issue #12 - July 2015 | Page 24

Rovering across the Moon Premier of the J-series mission changed the game for Apollo 15 By Ben Evans Four hundred miles (640 km) to the north of the Moon’s equator lies a place called Hadley: a small patch of Mare Imbrium at the base of the Apennine Mountains, some of which rise to 4,000 feet (1,200 meters), and a 25-mile (40 km) meandering gorge, known as Hadley Rille. In July 1971, Apollo 15 astronauts Dave Scott and Jim Irwin expertly negotiated these forbidding landmarks in the lunar module Falcon and set down in one of the most visually spectacular regions ever visited by mankind. They brought back a scientific yield which revealed more about the Moon’s origin and evolution than ever before. Forty-four years ago, this month in July-August 1971, Apollo 15 conducted one of the most brilliant missions ever undertaken in the annals of space science. It is therefore ironic that this triumph actually arose from the ashes of defeat. Original plans called for 22 22 four H-series lunar landing missions— Apollo 12 through 15—which would each spend 33 hours on the Moon and feature two EVAs. The final missions, belonging to the J-series, would perform longer missions, spend 70 hours on the surface, make three EVAs and utilize a batterypowered rover. In September 1970, everything changed when NASA canceled one H-series mission and one J-series mission; as a result, the schedule shifted to maximise the scientific harvest from the remaining flights. Apollo 15 was upgraded to the ambitious J-series and it was this decision which altered its scope and its place in history. The countdown on 26 July 1971 was near-perfect. In fact, Launch Director Walter Kapryan described it as “the most nominal countdown that we have ever had”. The astronauts— Scott, Irwin and command module pilot Al Worden—were awakened early that morning, breakfasted on steak and eggs, caught a brief nap as they were being suited-up and were helped into their couches aboard the Apollo 15 command module, Endeavour, at around 7:00 a.m. EDT. The clang of the hatch shutting them in startled Irwin. “I think that is when the reality of the situation hit me,” he later wrote in his memoir, To Rule the Night. “I realized I was cut off from the world. This was the moment I had been waiting for. It wouldn’t be long now.” From his couch on the right-hand side of the spacecraft, Irwin had little to do and had some brief respite to reflect on his life, consider the enormity of the mission ahead of him and, more than anything, give himself over to an air of anticipation and expectancy as he waited for the Saturn V to boost them toward the Moon. Fifteen minutes before launch, they had felt and heard the unearthly clanking noise of the access arm moving away from the spacecraft, then beheld the stunning blaze of sunlight through the command module’s only uncovered porthole . As the www.RocketSTEM .org