After pressing some buttons to start up the ascent engine of their lunar module Challenger, astronauts Gene Cernan and Harrison Schmitt left the Moon on December 14, 1972. That’s 39 years ago – before many of us were even born. While these men looked out the tiny triangular windows of the lunar module to see the lunar surface getting farther away, viewers around the world watched that same spacecraft leave the Moon, live and in color on their television sets. Departing the Moon for the last time was (not surprisingly, perhaps) far less interesting to most people than Apollo 11’s first landing over three years prior. Some evidence even suggests that NASA had to pay television networks to cover Apollo 17’s mission at all. Despite all their hard work and technological developments, the final liftoff of humans from the Moon came and went with just a brief notice on the nightly news.
That story, however, overlooks the difficulties engineers had in developing the ability to show the lunar module rocketing back into space. Television cameras of the late 1960s and early 1970s were notoriously bulky, usually requiring huge rolling bases or portable stands. For space use, any piece of equipment needed to be light-weight and easily portable. NASA awarded contracts to build television cameras for Apollo alternately to RCA and Westinghouse, and both companies managed to build units for different missions that met NASA standards for weight, materials, and functionality. For the final three Apollo missions, RCA provided small, portable, color television cameras that could show the astronauts stepping off the lunar module and onto the Moon, and then be moved to a stand or the lunar rover for mobile exploration.
The cameras were very successful, capturing images of numerous EVAs that included sample collection, a driver’s eye-view from the mobile rover, and the pitfalls of trying to just stay standing in a space suit in 1/6 gravity. For the lunar liftoff though, engineers had numerous calculations to make prior to the mission to allow for filming. Attached to a pan and tilt unit, the television camera could be controlled directly from Earth via a large high-gain antenna on the rover. Since signals to and from Earth are delayed by a few seconds due to the 240,000 mile distance, mission engineers suggested pre-programming the lunar module liftoffs for Apollo missions 15, 16, and 17. Based on mathematical calculations, the rover would be driven and left some distance from lunar module, and the camera would automatically tilt up to show the ascent when commanded by the operator on Earth. That was the plan at least.
On Apollo 15, the tilt mechanism malfunctioned and the camera never moved upwards, allowing the lunar module to slip out of sight. And while the attempt on Apollo 16 gave a longer view of the lunar module rising up, the astronauts actually parked the rover too close to it, which threw off the calculations and timing of the tilt upwards so it left view just a few moments into the flight.
Thankfully, for NASA, those watching at home, and anyone reviewing film footage today, the third attempt was the charm. Cernan and Schmitt parked the rover at just the right distance, all of the mechanisms worked flawlessly, and viewers can still see today how that awkwardly-shaped ascent stage keeps going up until it becomes just a bright speck the sky on its way back to the command module.
How we saw and continue to see the Apollo program is due not only to the engineers at RCA for creating this unique ability, but also the NASA camera operator in Houston, Ed Fendell, for getting the timing just right, and NASA itself for recording and preserving these moments for our collective memory of our last departure from the Moon. How big of a part do you think NASA's television coverage of Apollo 17 plays in how we think about that time period? Do you think the same is true of the end of the Space Shuttle program in 2011?
A view of the Apollo 17 landing site as seen from the lunar module ascent stage as it left the surface. On the left, you can see the descent stage, the small gold-colored circle, and numerous tracks leading away from it, marking the paths astronauts took on their extra-vehicular activities.