Words have meaning: Hold (Hold Hold)

The last few minutes of a launch are very critical. It is at this time that systems on the launch vehichle, and (for some missions) the payload, are switched from using an external power source to using their internal batteries. For Delta launches, this switch usually occurs four minutes before launch, and gives the final insight into the complete health of the system. At this point, if any data indicates a possible problem it is necessary to quickly stop the launch.

In mission operations, words that indicate a specific, time-critical action must be very precise. In this situation, the words used by an engineer to the launch director to stop the launch are:

Preparing to launch a multi-million to multi-billion dollar observatory requires practice. So the last six months prior to launch are filled with practices. “Mission rehearsals” that exercise the post-launch and activation process are very complicated, and are run repeatedly by the mission operations team. “Launch rehearsals” that practice the pre-launch process are performed jointly with the launch vehicle operations team several times before launch. During launch rehearsals, one of the hardest things for me to learn was never to say the word “hold.”

Saying “hold hold hold” only has consequences if you say it on the particular communications channel (voice loop) that is connected to the launch operations team, and I never had any reason to be on that loop. Even so, I spend the last few months finding alternative words to use. “Please carry this for me,” rather than “Please hold this.” “Can you wait a minute,” rather than “Can you hold on.” And the list goes on…

It seems like such an innocuous word, hold, until you realize that with that one word you have the power to stop a launch. And right before launch, even a one day delay is a LOT of manpower, and money. But that’s not nearly as painful as the investigation that would follow a failed launch.

You hope you never have to say “hold hold hold.” But if something’s not right, it’s absolutely the right thing to do…

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