John H.L. Hansen stands next to the SoundScriber, the only device that could play the analog recordings of thousands of hours of communications during NASA’s lunar missions.
Credit: The University of Texas at Dallas


Listen up!

Previously unheard communication between Apollo astronauts, mission control and backroom support staff is now available given speech-processing technology utilized by a team of researchers at The University of Texas at Dallas. uses signal, speech and language processing algorithms to extract new information, merge information sources, and provide a new perspective on the NASA Apollo missions.

Analog tapes

Thousands of hours of communications remained stored on analog tapes at NASA for years.

From left: John H.L. Hansen, Chengzhu Yu, Abhijeet Sangwan and Lakshmish Kaushik. The four oversaw the project to develop speech processing techniques to reconstruct and transform thousands of hours of audio from NASA’s lunar missions.
Credit: The University of Texas at Dallas

Researchers at the University’s Center for Robust Speech Systems (CRSS) in the Erik Jonsson School of Engineering and Computer Science (ECS) received a National Science Foundation grant in 2012 to develop speech-processing techniques to reconstruct and transform the massive archive of audio into Explore Apollo.

The result: Explore Apollo is a website that provides public access to the materials. The project, in collaboration with the University of Maryland, included audio from all of Apollo 11 and most of the Apollo 13, Apollo 1 and Gemini 8 missions.

Explore Apollo website.
Credit: The University of Texas at Dallas


When they began their work, researchers needed to digitize the audio.

However, transferring the audio to a digital format proved to be an engineering feat itself. The only way to play the reels was on a 1960s piece of equipment at the NASA Johnson Space Center in Houston called a SoundScriber.

“NASA pointed us to the SoundScriber and said do what you need to do,” said CRSS founder and director John H.L. Hansen. The device could read only one track at a time. The user had to mechanically rotate a handle to move the tape read head from one track to another.

Credit: The University of Texas at Dallas

Solution: 30-track read head

By Hansen’s estimate, it would take at least 170 years to digitize just the Apollo 11 mission audio using the technology.

“We couldn’t use that system, so we had to design a new one,” Hansen adds. “We designed our own 30-track read head, and built a parallel solution to capture all 30 tracks at one time. This is the only solution that exists on the planet.”

The results of their work can be found here at:

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