11. Project Apollo, Part 2

Submitted by sondra on Sun, 09/11/2011 - 11:00am

by Gus Posey, The Museum of Flight   John Young on the moon during the Apollo 16 Moon Landing in April 1972.- Photo Courtesy of NASA

On April 11, 1970, a Saturn V rocket designated SA-508 roared off launch pad 39A at the Kennedy Space Center carrying the Command Module “Odyssey” and the Lunar Module “Aquarius,” commonly referred to as Apollo 13. At its simplest, the mission was mankind’s third trip to the moon, but quickly became a life or death struggle against the hostile environment of space.

Following two successful trips to the moon, the famously fickle American public had turned their attention away from manned spaceflight, focusing instead on the arrival of the AMC Gremlin and the breakup of the Beatles. The perception was that the astronauts were merely walking in the footsteps of previous lunar explorers, on a routinely repetitive mission to the moon. Of course, no such mission exists; each lunar mission was designed to incorporate a wide range of scientific experiments from a variety of disciplines. For example, previous missions had been calculated to produce an orbit for the Saturn’s upper stage that would take it around the sun. Apollo 13 marked the first time that mission planners intentionally guided the stage into a lunar impact, to be measured by seismometers left by earlier missions.

Slightly less than 56 hours into the mission, Command Module pilot John “Jack” Swigert received instructions from CapCom (Capsule Communicator) Jack Lousma. “13, we’ve got one more item for you, when you get a chance. We’d like you to stir up the cryo tanks.” Lousma also offered shaft and trunnion information for Comet Bennett, one of the mission’s photographic targets. Swigert responded, saying, “ Okay, stand by.” After switching on the oxygen tanks’ internal fans, readouts within the spacecraft began to indicate a serious problem. Some displays showed power fluctuations, while others described changes in temperature and pressure within the oxygen tanks. After switching off the master alarm, Swigert sent a famous, if often misquoted, message to Earth: “Okay, Houston. We’ve had a problem here.”

The problem was serious, and the result of a complicated chain of events. Insulation on the fan wires had been damaged by overheating, a situation that originated with damage caused on Earth, while the spacecraft was being assembled. A short circuit from exposed fan wires inside the tank immediately ignited the pure oxygen, quickly raising the pressure of the tank beyond its abilities to contain. The tank exploded, impacting the oxygen tank next to it, blowing off one of the spacecraft’s side panels, and damaging the ship’s high-gain antenna.

Apollo 13’s trip to the moon was aborted, and NASA’s teams began to work out solutions for keeping the astronauts alive in space and returning them to Earth. Despite the extraordinary challenge, engineers on the ground were able to provide methods for using the Lunar Module as a lifeboat in space. It was not until the astronauts had traveled around the moon and back to Earth that they were finally able to jettison the lifeless Service Module and see what the damage looked like. Jim Lovell described the craft, perhaps best left unexamined until that point. As it drifted away, Lovell said of the Service Module, “There’s one whole side of that spacecraft missing.” Soon after, the Apollo 13 crew returned to Earth, grateful to be home, but frustrated at having missed their chance to walk on the moon.

For the American space program, the Apollo 13 accident was an incident to be taken seriously, and it demanded a comprehensive investigation. At the same time, however, the nail-biting return of America’s three stranded astronauts had been covered around the world, returning the Apollo missions to the front pages and the headlines of the evening news.

When the next Saturn V left its pad in January 1971, there was an increased awareness of the dangers involved. While this did not necessarily propel NASA operations to the top of the television ratings charts, it did help to erode the idea that trips to space could ever be routine. The flight of Apollo 14 demonstrated that fact in slightly less dramatic fashion, suffering weather-related delays and, during their translunar injection, difficulties in docking the Lunar and Command Modules. Six attempts were required before a set of stuck docking rings finally deployed. A successful mission overall, Apollo 14 also marked the return to space of Alan Shepard, who had become the first American in space 10 years earlier.

Just six months later, Apollo 15 returned to the moon, carrying astronauts David Scott, Alfred Worden and James Irwin. This mission carried the Lunar Roving Vehicle (LRV) to the moon for the first time, allowing Scott and Irwin to explore a much larger area of the moon than had been possible during previous missions. After their final excursion, David Scott presented a televised demonstration of a hammer and a feather falling at the same speed, the moon’s airless surface providing a unique and ideal environment for the experiment.

Apollo 16 was launched in April 1972. As was the case with the previous flight, the spacecraft carried another LRV, folded neatly into the Lunar Module “Orion.” During their visit to the moon, John Young and Charles Duke explored approximately 17 miles of the lunar surface. Like all of the previous moon landings, the astronauts set up experiments, collected samples and documented the stark environment with film and photographs.

On December 7, 1972, NASA launched the sixth, and final, manned mission to the moon. The Apollo 17 spacecraft performed flawlessly during its mission, and allowed Eugene Cernan and Harrison Schmitt to fully utilize the LRV, this time covering more than 19 miles. Schmitt is generally recognized as being the first scientist on the moon.

Almost three years before the flight of Apollo 17, budgetary constraints and a lack of political will forced the cancellation of the final lunar mission, what would have been Apollo 20. In September 1970, Apollo 18 and 19 were also cancelled. Humans have not been to the moon since Cernan and Schmitt departed aboard the ascent stage of the Lunar Module “Challenger.” Thirty-five years later, plans are finally on the drawing board for a new vehicle that will transport six astronauts to the moon. Like the Apollo spacecraft, this new attempt will allow further exploration of our closest celestial neighbor, and will, one hopes, remind us why we must continue searching.