Lunar Orbiter Image Recovery Project - Hardware and Funding

Hardware and Funding

In a completed and working magnetic tape drive system, the tape-drive heads apply a very specific magnetic field to the tape; the tape then induces a change in electrical current, which is captured. The data from the Lunar Orbiter tapes is then run through a demodulator, and through an analog-to-digital converter so that it can be fed into a computer for digital processing. Each image is divided up into strips on the tape, so the computer is used to bring the strips together to create a whole image. Before even beginning the project, the team evaluated the risks and determined that there were two: one was that the tapes had deteriorated to the point where they could not be read; the second was that the tape drives would not be able to read the tapes. The milestones of the project were developed to test these risks as soon as possible with the least amount of money spent.

Once the project started in earnest in July 2008, results came quickly. In only a couple of weeks, the first tape drive had been powered up, although it was clear that many parts still needed to be replaced. Another week of cleaning and testing revealed that among the four drives and batches of spare parts there were enough good power supplies to run one of the tape drives, and there was at least one working head for the drive. The head is the mechanism that touches the tape and reads and writes data, so it is absolutely critical; in the case of the Ampex FR-900 tape drives, the heads were not manufactured after 1974, cannot be replaced, and can only be refurbished at great expense by a single small company.

After another month of repairing and replacing parts, testing and tuning mechanisms, the project got the first solid result that the tapes were good. Each tape starts with a short standard-format audio clip of the operator, and the tape drives were able to read the audio signal. (Hear a sample of the audio.) This does not use the video heads that are needed to read the Lunar Orbiter data off the tape, but this demonstrated that the tapes had not deteriorated and that many of the sub-systems of the tape drive were in good working order.

The documentation for the tape drives was substantially incomplete, which kept the team from understanding the right way to repair, maintain, and use the tape drives. The search for documentation has been extensive and usually disappointing, as it often turns out that retired or elderly engineers have just recently cleaned out their garages. Posting to a blog, Dennis Wingo said, "I cannot tell you how many times we have heard similar stories of recently tossed manuals over the last six months". At just the right moment the team heard from a friend of a friend that a mother lode of maintenance documentation stored on aperture cards (microfilm embedded in computer punch cards) had been saved by the retired head of Ampex field engineering. This documentation would make it possible for the team to understand the correct procedures for repairing the tape drives and aligning the mechanics.

At this point in the restoration, the demodulation of the tapes had become the biggest issue. The team was not sure if the demodulation board that came with the system was the correct one, if they needed a different one, or if they needed this one and another one. At the same time, they discovered a tape, which, from the audio clip at the start, sounded as if it contained a demodulated recording of one of the images. This was a lucky break, as it meant that a demodulator would not be needed to generate images from this tape. If the team could rescue this image, the project would prove "that the drive can be refurbished to the point of reliably playing a tape back". Work continued, and the team coined the term "technoarchaeology" to describe the process of researching which tape contained what image. Posts to the blog continued, but with little substance until suddenly NASA announced a press conference.

On November 13, 2008 NASA held a press conference and announced that they were releasing the first image that had been restored: a striking image, taken on August 23, 1966, of the Earth as viewed, for the very first time, from the Moon. This was a major milestone that showed that the tapes and the tape drives were both good. Preliminary analysis showed that the image had "four times the dynamic range of the ... film image and up to twice the ultimate resolution". The NASA Exploration Systems Mission Directorate (ESMD) had sponsored the team so far with a small grant of $100,000. With these results, more funds were released—another $150,000 to complete a major restoration of the drives and to create the demodulation hardware needed for the other tapes. Gregory Schmidt, deputy director of the NASA Lunar Science Institute at Ames said, "Now that we've demonstrated the capability to retrieve images, our goal is to complete the tape drives' restoration and move toward retrieving all of the images on the remaining tapes".

Within a month, the next round of funding came through and restoration began in earnest. The heads, capstan and rotor motors were being restored by two different companies. New documentation about the demodulation was discovered, and the team began building a board by hand. Custom belts were being manufactured to replace the old ones. Software was being written to process the digital images. The biggest expense was the heads, which cost around $8,000 each to be refurbished.

On March 21, 2009, the team announced that they had rescued an un-demodulated image from one of the tapes, using the newly perfected demodulation system. The image, of the crater Copernicus, is from the Lunar Orbiter 2 spacecraft taken on November 24, 1966. NASA Scientist Martin Swetnick was quoted in a Time magazine article from 1966, calling this image "one of the great pictures of the century".

By April, the team had digitized 30 images. A couple of months later an article in ComputerWorld revealed that the project had a new grant of $600,000, and had hopes to completely digitize all the images by February 2010. Most of the new funding came from NASA, but about 10% came from other donors. This new funding allowed the team to restore a second tape drive to full operation by November 2009, which made the process of restoring the images that much faster.