Newsgroups: sci.space.shuttle
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: Built in Holds in Countdown
Message-ID: <1988Sep19.111225.4591@utzoo.uucp>
Organization: U of Toronto Zoology
References: <10358@reed.UUCP>
Date: Mon, 19 Sep 88 11:12:25 GMT

In article <10358@reed.UUCP> reeder@reed.UUCP (P Douglas Reeder) writes:
>Why are there built-in holds in the countdown?

Because ticks on the countdown clock have come to denote progress toward
launch, as opposed to the passage of time per se.  Since minor glitches
are not uncommon, there needs to be some slack time allowed for fixing
them.  So there are periods when, if no glitches have appeared, no actual
progress is being made toward launch and the clock is stopped.

That's my understanding of it anyway.  It's always seemed kinda silly.
-- 
NASA is into artificial        |     Henry Spencer at U of Toronto Zoology
stupidity.  - Jerry Pournelle  | uunet!attcan!utzoo!henry henry@zoo.toronto.edu