I've recently come across this strange sentence, which I believe is a command spoken by NASA astronauts, "Apollo, you are Go" and it sounds grammatically incorrect since "go" is a verb and not an adjective, it's unlikely to be an abbreviation or even a grammatical mistake as the people working there must be well-educated. So, please enlighten me on this. Thanks in advance.enter image description here

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    This is second nature for those of us who grew up having breakfast while watching NASA launches on TV. "You are GO for launch" means all the items on the checklist have been checked off so you are cleared to launch -- your status has been marked "GO".
    – Hot Licks
    Sep 3, 2020 at 21:16
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    In military, aviation, space, etc contexts it is more important for spoken communications over radio to be clear and unambiguous than it is for them to be grammatical. For safety reasons for one thing. Sep 3, 2020 at 21:29

1 Answer 1


I read it as a predicate adjective meaning roughly that "you" (the astronaut team in Apollo 8) is ready for launch. This usage is also seen in the idiom "all systems are go." Here's how the Oxford English Dictionary describes the usage:

  1. colloquial (originally U.S.). Chiefly in predicative use. Functioning properly; ready and prepared; fulfilling all conditions necessary to proceed. Originally with reference to devices and systems in a spacecraft.

The usage goes a little further back than NASA. Here is an excerpt from a 1958 book Rocket to the Moon, which is a researched account of what a space program capable of going to the moon would look like:

"Azusa-go! DOVAP-go! Telemetry one, two, three (etc.)-go!"

Trouble anywhere and the report is "No go!" and down goes the hold switch. All come in "Go!"

[...] "T minus 30 seconds. All systems-Go!"


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