by Bill Anderton
As discussed on the Apollo 11 Video System page, the video we all saw on our TV sets was sub-optimal as a result of both using SSTV and then the scan-conversion process that was used. The quality was further degraded by its long and noisy analog distribution links.
The raw unconverted slow-scan television signals from the Unified S-Band Signal Data Demodulator (SDDS) were recorded onto 14-channel 1-inch analog instrumentation magnetic tape. At the time, the primary reason for making these recording was a backup in case the RCA Slow Scan Converter failed.
However, the RCA Slow Scan Converter never failed so the tapes never got much thought after the moon landings. As strange as it sounds in retrospect, nobody was thinking about the historical implications of the tapes and the almost certain likelihood that the technology would improve in the future and could ring more quality from the raw tapes.
The thought of going back to raw slow-scan recordings was sparked when several still photographs appeared in the late 1990s that showed the superior raw SSTV transmission on ground station monitors from the Sydney Australia video control center. This triggered the first hunt for the tapes.
The multinational multiyear search came to the conclusion that the 1-inch tapes with the recorded SSTV signal were shipped from Australia to the Goddard Space Flight Center and then, a few years later, were routinely erased and reused. Australian backup tapes also sent to Goddard were also erased and reused after Goddard received these reels using procedures established by NASA at the time.
NASA was facing a profound shortage of magnetic tape after launching new satellites producing significant amounts of data (like Landsat) that required recording. To cope with the shortage, NASA turned to recycling.
With incredible short sidedness and without thinking about the historical value of future processing and enhancement of these tapes, Goddard was instructed to reuse many of the archived tapes in NASA warehouses for recording data from its new satellites. NASA recycled tens of thousands of archive video tapes of all types. Unfortunately, the Apollo 11 tapes are now assumed to have been caught up in the recycling.
As a result, none of the Apollo 11 raw slow scan television recordings are known to exist today; a major and embarrassing "whoopsie" for NASA.
Frankly, considering all of the technical "givens" at the time, the video broadcast at the time this was just about as good as it could have been. However, one can only imagine the resulting video we could see today if the original raw slow-scan tape had been preserved and subjected to today's modern digital video processing technology.
A hint of the potential improvement comes from two Polaroid pictures taken during the moon walk. Above, the photo on the left was taken directly off a Fairchild 320 line, 10 frames per second monitor located at Sydney video control room. The photo on the right was taken off an NTSC monitor after scan conversion in the same room. Comparing the two photos shows the loss of resolution and shadow detail that occurred during the conversion process. While these examples are only still photos taken from video monitors (also a form of optical transfer), the comparison does provide a direct example of the degradation in the scan conversion process that was used. They also provide a glimpse of what might have been possible with advanced digital video processing.
In the technology advancements since 1969, digital frame-buffering and scan-conversion technologies have improved by orders of magnitude. In a perfect world, the archived tapes of the raw slow scan television signals recorded from the 64-meter downlink antenna signal path could have been digitized and processing using all of the modern software techniques available today.
From the NPR story:
They returned again and again to that vast government warehouse. But then they discovered something disturbing.
Over the years, NASA had removed massive numbers of magnetic tapes from the shelves. In the early 1980s alone, tens of thousands of boxes were withdrawn.
It turns out that new satellites had gone up and were producing a lot of data that needed to be recorded. "These satellites were suddenly using tapes seven days a week, 24 hours a day," says Lebar.
And the agency was experiencing a critical shortage of magnetic tapes. So NASA started erasing old ones and reusing them.
That's probably what happened to the original footage from the moon that the astronauts captured with their lunar camera, says Lebar. It was stored on telemetry tapes, and old tapes with telemetry data were being recycled.
"So I don't believe that the tapes exist today at all," says Lebar. "It was a hard thing to accept. But there was just an overwhelming amount of evidence that led us to believe that they just don't exist anymore. And you have to accept reality."
Still, Nafzger says, they didn't want to give up completely on their mission. "Our goal was to provide to the world the best possible video of a historic event we could for the future," he says.
Without the original tapes of the raw slow-scan television from the Moon, NASA did begin an important restoration project of the 2-inch video recordings and kinescope films in NASA's archives to provide the best possible recordings of the Apollo 11 moon walk.