NASA - National Aeronautics and Space Administration

Image Above: Apollo 11 Lunar Module Pilot Buzz Aldrin. Credit: NASA

You're in a spacecraft, descending to land on the moon for the first time in history, and the microphone to Earth is off. What do you say?

"I would appreciate if you could ... see if you could ... find the map ..."

"Trade you that for a piece of gum. There it is."

And so it went as Neil Armstrong and Buzz Aldrin descended to the surface of the moon aboard the Lunar Module Eagle on July 20, 1969. The world heard communications between the crew and Mission Control live as they happened. But Earth did not hear the conversation between Armstrong and Aldrin, although it was recorded onboard the Eagle.

All of the Apollo spacecraft included onboard voice recorders, activated during much of each mission to record the crew's conversations. The transcripts of those recordings were publicly released in the mid-1970s and they have been posted on the Internet for years. But only recently were the actual onboard recordings from Apollo 11 digitized so that the recordings could be made available on the Internet.

The Apollo 11 Onboard Audio Tape Database cross references the tape numbers to the Mission Elapsed Time (MET) that was on each tape. The database includes a description of the mission status at that time. It is best to listen to the tapes while simultaneously viewing the same mission elapsed time on the transcript, since often the recordings are faint.

The digitized recordings are available here in the same form as they were recorded during the mission. As a result, they are noisy with technical interference that occurred during their recording and transmission. They are sometimes garbled and sometimes have long periods of no voice. They are not listed in chronological order but rather in the order that data was dumped onto storage tapes during the mission. A single tape may include recordings from several different periods of the mission.

The equipment onboard the Apollo Command Module that was used to make the recordings was called the Data Storage Equipment (DSE). Its contents were transmitted to the ground periodically during the mission. Also, the Command Module DSE had the capability to record data live during certain periods from the Lunar Module as it flew separately in lunar orbit. The equipment used aboard the Lunar Module to make the recordings was called the Data Storage Electronics Assembly (DSEA). It made recordings onboard the Lunar Module, but the DSEA flown on the Eagle during Apollo 11 malfunctioned. As a result, many of its recordings are barely, if at all, audible, with a constant high-pitched background tone. In the attached database, the recordings that are virtually inaudible are highlighted, but they are available on the web to ensure a complete release of the recordings made during the mission.