The Apollo 11 mission in July 1969 culminated in the first time a person stepped onto an extraterrestrial body. As Neil Armstrong descended the ladder of the Lunar Module, Eagle, billions of people around the world watched the grainy, black-and-white images in real-time. The iconic broadcast footage of the first step was not captured by a cameraman or a typical video camera. The images were transmitted by a specialized, externally mounted television camera designed for the rigorous demands of the lunar environment.
The Source of the Iconic Feed
The equipment that filmed Neil Armstrong’s historic descent was the Westinghouse Apollo Lunar Television Camera, a small, black-and-white video unit engineered for the mission. This camera was mounted externally on the Lunar Module’s descent stage, stowed within the Modularized Equipment Stowage Assembly (MESA) on the side of the Eagle.
To begin the broadcast, Armstrong pulled a lanyard while still on the ladder, triggering the deployment of the camera. The MESA door swung down, positioning the mounted camera to capture the ladder and the surrounding lunar surface. The camera’s placement, which was slightly tilted, provided the world with the ground-level perspective of the first step. This Westinghouse unit was powered by the Lunar Module and was left behind on the Moon’s surface to save weight for the return journey.
The Technical Challenge of Transmission
The live broadcast seen by the world was low-quality, a result of the challenging transmission process, not the camera itself. The Westinghouse unit transmitted its signal using Slow Scan Television (SSTV), a format necessary due to the Lunar Module’s limited bandwidth. This specialized system transmitted images at a slow rate of only 10 frames per second with 320 lines of resolution.
The commercial television standard (NTSC) used in the United States required 30 frames per second and 525 lines. To make the SSTV signal viewable on standard home televisions, it first had to be received by ground stations equipped with large dish antennas, such as those at Goldstone, California, and Honeysuckle Creek and Parkes in Australia. The raw SSTV signal was fed into an RCA optical scan-converter, which displayed the image on a dedicated monitor. A standard broadcast camera then filmed this monitor screen, converting the slow-scan image to the NTSC standard for global distribution. This two-step conversion process introduced the visible degradation, resulting in the blurry image that became the famous live feed.
Secondary Cameras and Imagery Sources
While the live broadcast captured the first step, other photographic equipment provided high-resolution images and motion footage from the lunar surface. The astronauts used specially modified Hasselblad 70mm cameras for still photographs. These cameras, mounted to the astronauts’ chest plates, produced the detailed images of Buzz Aldrin and the American flag.
For additional video footage, the Apollo 11 crew carried two 16mm Maurer Data Acquisition Cameras (DAC). One DAC captured the actual landing through the Lunar Module window, and the other filmed the astronauts’ activities on the surface. This motion picture film, shot at various frame rates, provided clearer, higher-resolution video than the live SSTV broadcast. This footage was not seen by the public until the film magazines were returned to Earth and developed.