In the first edition of Andrew Chaikin's 1994 book, "A Man on the Moon, there is a paragraph in chapter 1 which talks about troubles the Apollo 1 testing crew were going through.

Chaikin states that on January 27, 1967 around 1 pm just after testing had started, Grissom smelled something like sour milk. It took the crew about an hour to find the source of the smell, and the testing continued.

Here is the specific excerpt from the book:

Today's simulated countdown was nothing new; it wasn't considered dangerous-The Saturn booster was not fueled-or even difficult. But there was trouble almost from the time Grissom and his crew climbed into the command module cabin, around 1 pm. First there was an unidentified odor in the breathing oxygen that reminded Grissom of sour milk; that alone held up the test for an hour. Finally the problem was solved, and at 2:45 P.M. the pad crew installed the command module's heavy, two-piece hatch and sealed it shut.

As you can see, Chaikin never really mentioned what exactly was causing the smell or how they fixed it.

However, I am curious about this. Does anyone know what exactly was causing the smell that Grissom smelled, and how they fixed the problem?


2 Answers 2


The only further information I've ever seen on the odor is in the paper "Accidents, Engineering, and History at NASA" which states in a footnote that

Sour milk smell is characteristic of butyric acid, which was a constituent element of a number of plastic products in the 1960s.

I can not find any evidence that anything was done to resolve the problem, just that air samples were taken for future analysis. The Timeline states that the cabin was purged with oxygen, but does not make it clear whether this was because of the odor, or a planned event.

  • $\begingroup$ Interesting. I would have thought is had something to do with the oxygen itself inside of the cabin. Do you know if they had used plastic with butyric acid in other spacecraft before? It would seem somewhat strange that it would be such a mystery if they had used such plastic in other spacecraft. $\endgroup$
    – Chris
    Jun 19, 2017 at 20:08
  • 5
    $\begingroup$ Plastic producing a sour smell due to butyric acid are not rare. My dad had a drawer of screw drivers with rubberized handles which produced this smell. $\endgroup$ Jun 19, 2017 at 20:20

Calculated Risk: The Supersonic Life and Times of Gus Grissom says:

Donald Babbitt, the North American Aviation pad leader who arrived in the White Room for his normal shift about 3:30 pm, later told investigators the smell "reminded [him] of a potting compound" used in spacecraft assemblies for waterproofing and to withstand shock and vibrations.

The book also backs up the statement in Organic Marble's answer that an air sample was taken and there was no actual solution to the problem at the time.


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