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How the Eagle Landed — the Grumman Construction Log

On July 20, 1969, Eagle landed on the moon. These are the handwritten notes from the Grumman engineers as they pushed to complete Lunar Module LM-5 in 1968. On the last page, they learn than this particular Lunar Module would be the one to bring the first humans to the moon. (That page and several others can be seen here.)


The Grumman Engineering Log served not only as an engineering notebook but also as an intercom between the day and night shift – separate teams that needed to push the ball forward from where the other left off. So we are offered a rare peek into the concerns, uncertainties and conversations that might have otherwise been quietly undocumented .


This log has informed the writing of Pellegrino’s book Chariots for Apollo, but only a few scholars have had access to these pages to date. Heritage reported that this original document is the only one in existence, with no copy on file anywhere. So I thought it would be good to make a color scan of the entire book, and make it available to all. So, here is the PDF file (8MB).


My hope is that we can collectively decode some of its mysteries, or better yet, find some of the engineers to see if it jogs their memories. There is a list of all of the engineers on p.2. We only have first initial and last names. So any insights to the full names or their whereabouts would be appreciated.


I am also hoping that space historians who come across interesting passages can share what they know in the comments below (with reference to date or page number). Are any of the part numbers significant, especially those swapped between the Apollo 9,11,12 and 13 Lunar Modules? I will also add a glossary of acronyms below as we decode them. Also, if anyone can OCR the hybrid handwriting, please do. Our attempts with free OCR tools have failed so far.


The Log documents a surprisingly high number of electrical problems. For example, in the sample pages I photographed above they are troubleshooting charred wires (10/17/68) and tripping circuit breakers (CB) just seven months before launch (12/11/68). Ross Fleisig summarizes: the Lunar Module was a completely battery-operated machine, built during a time in which battery technology and sensing equipment were "a black art." (the first Apollo fuel cell, with comments on power source development)


False alerts from the ship's Master Alarm are noted throughout the Log (e.g., 6/18/68). This is the very same Master Alarm that sounded throughout the first lunar landing, almost causing a mission abort.


There are also personal notes of exhaustion. When I analyzed the work schedule on a 1968 calendar, they generally maintained a pace of working Monday through Saturday. They did get a reprieve for the July 4 weekend, but then worked seven days a week from July 8 until July 27. While such pushes are not unusual, they did so while rotating through day and night shifts on a weekly basis!


No wonder Hecht makes several personal comments, arising from lack of days off and even lack of meals, as a docking light hook-up error is discovered (8/5-7/68): “Techs & QC had no breaks nor breakfast” after “docking light wires in plastic bag warm” from a hookup error to the AC instead of DC terminal posts.


Some other interesting entries:

6/6/68: floor plates in crew cabin are borrowed from LM-3 (Apollo 9) and other parts on 6/25/68.

7/16/68: exactly one year before the launch of Apollo 11, testing delayed by power outages from the Long Island utility.

7/20–26/68: modifications improving efficiency of battery use will prove critical to the safe voyage of a LM-7 (Apollo 13), simultaneously under construction.

10/17/68 “to unlatch the meter and restore the AC output, the meter relay reset button should be pressed. The GPS man had accomplished this same result by banging the panel, assuming it was a sticky needle” (the Fonz!)

10/18/68: Landing radar connector problems, current surges and popped circuit breakers

10/22/68: “power was lost . CRT’s, etc., went blank. Docking hatch switch is taped in the depressed position. The tape just fell off.”

“Observer said that the floodlights flickered in unison with the RCS jets firing. NASA was not too concerned about this”

10/23-24/68 landing radar tests

11/6/68 “dim DSKY lights are probably a DSKY problem and require action w MIT”, final radar and comm tests before shipping LM-5 to Cape. The DSKY is the keyboard and screen user interface to the Apollo Guidance Computer.

11/11/68: reversed labeling of LM-5's internal jumper cables

11/13/68 Hecht asks for max of 8 hrs on Fri and Sat

11/15/68 “any time the inverter frequency drifts ± 2 Hz we may get a master alarm and an inverter caution.”

11/30/68 COAS test (the optical sighting tool that allied the ascending lunar module to dock with the orbiting CSM)

11/20/68 Phase III Reliability Report: "Reportable failures have gone down from LM-3, to LM-4, to LM-5 (205 to 74 to 57)... Significantly improved vehicle”

Bob Gilruth (NASA Director of the Manned Spacecraft Center): “some tough technical problems left, but thinks they will be solved”


George Low (Manager of the Apollo Spacecraft Program Office): “this is very likely to be the LM to land on the moon - it should be."


The engineers added a huge exclamation point next to that note.


P.S. other Apollo 11 artifacts. Happy Anniversary!

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Taken on July 17, 2012