On choosing the exact right terminology

From How Apollo Flew to the Moon (W. David Woods, 2011). It is July 20, 1969, and the Eagle has just landed:

Go/no-go decisions had punctuated the flight thus far and now the flight director wanted his controllers to make another, this time on whether the surface phase of the mission should continue — but he wasn’t going to call it “go/no-go.” It had been pointed out by Bill Tindall that in the heat of an emergency, “Go” could easily be construed as advice to get out of there as much as an instruction to continue with the planned mission and stay on the surface. Therefore this call was “stay/no-stay.”

Howard Wilson “Bill” Tindall (1925–1995), Chief of Apollo Data Priority Coordination, had responsibilities described by Wikipedia as “wide-ranging.” His attention to detail went as far as optimizing the ergonomics of terms like “go/no-go.” Here is Tindall’s original note, from NASA’s archived collection of the memos affectionately known as “Tindallgrams.”

DATE: March 7, 1969


FROM: PA/Chief, Apollo Data Priority Coordination

SUBJECT: G Lunar Surface stuff is still incomplete

On February 27 we held a Mission Techniques meeting which I thought was going to simply edit the “final” version of the Lunar Surface Document prior to its release. To my chagrin we discovered that there are at least two areas requiring much more thought and analysis. We will probably meet again to resolve these during the last week of March. The release of the Mission Techniques Document will have to be delayed accordingly.

Before delving into these major items, there are a couple of other things I would like to mention. The first may seem trivial. It deals with terminology — specifically, use of the expression “go/no go” regarding the decision whether to stay or abort immediately after landing on the lunar surface. Every time we talk about this acitivity we have to redefine which we mean by “go” and “no go.” That is — confusion inevitably arises since “go” means to “stay” and “no go” means to “abort” or “go.” Accordingly, we are suggesting that the terminology for this particular decision be changed from “go/no go” to “stay/no stay” or something like that. Just call me “Aunt Emma.”

The memo continues for another five paragraphs on the “major items”:

Last summer GAEC honored us with their presence at one of our meetings and to celebrate the occasion we give them an action item. We asked them how to make the tilt-over decision and to establish the attitude and rate limits for aborting. We haven’t heard from them since, on that or anything else except RCS plume impingement. Don’t worry, we still have four months to figure out how to do it.


(Incidentally, given the Internet Archive’s heroic efforts to archive content from Tumblr before it went down, I’m starting to wonder if they’re putting a similar contingency plan in place for the U.S. federal government.)

Posted 2019-01-15