Why didn't the orbital probes in "The Arsenal of Freedom" shut down with the ground probes?

Question

Captain Picard manages to end the weapons' demonstration near the end of Season 1, episode 21 (The Arsenal of Freedom) by telling the hologram he'd buy the weapon system.

The ground based probe switches off immediately, which saves Tasha Yar and Will Riker from an attack. In contrary to what I'd expect, the orbital probe is still in pursuit of the Enterprise and doesn't shut down, as well.

I guess for the story arc of the ship crew it is a nice closure but is there an in-universe explanation for why the orbital probes did not shut down at the same time?

Answer 1

In-universe, it makes sense that the anti-spacecraft weapons would be autonomous, since they have to be able to function at a distance; you wouldn't want the enemy to be able to jam or fake the signals from the central computers. They could have been programmed with a separate demo mode in which the central computers can override them, but apparently they weren't; this isn't too surprising, since the Minoans don't strike me as a particularly careful race.

Certainly they weren't careful enough to keep the "demo mode" for the system as a whole from getting out of control - perhaps the demonstration was activated accidentally and was never intended for use on an inhabited planet or in the vicinity of manned spacecraft, or perhaps it was intended to behave in a more restricted fashion, only operating in a designated area of the planet and not launching attacks on spacecraft. Whatever they did, it didn't work. :-)

I don't think the "offer to buy" thing is a plot loophole either, or at least not a serious one. So far as we know, the crew of the Drake were the only visitors since the disaster (there might have been a few more, but probably not too many or the problem would have been noticed earlier) and it doesn't seem unreasonable to suppose that they were all killed before they had learned enough about what was going on to make the offer.

(Note that the AI salesman would of course be programmed not to try to sell to the residents of the planet; they're the people he represents, or perhaps potential competitors, not potential buyers.)

Out-of-universe, see Valorum's answer.

Answer 2

In-universe there appears to be no good reason other than that the system is apparently deeply malfunctional.

It stands to reason that if all it takes to shut it down is to agree to buy it, it beggars belief that at least one person didn't already try that ruse. The fact that bits of it are still deadly even though it's ostensibly shut down ties in very nicely with the idea that it killed everyone on the planet while in "demo mode".

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The out of universe reason is that this episode was a total trainwreck. The studio demanded an almost complete rewrite of the screenplay just days before the show was due to go into principal production, resulting in the film crew having to shut down while they waited for a finalised script. When it finally arrived, they were forced to shoot (and, crucially edit) for fewer days than normal.

"...the episode..., was in creative turmoil and going through a massive, last-minute rewrite. In five years, that was the only time the company had to shut down because there was no shooting script to be shot. I was familiar with the sets, cast and crew, so although the script was late in appearing, I had all the knowledge and background to go ahead and do my job. To this day, 'Arsenal' still stands out as one of the better shows, certainly one of the shows with the most production value of any we've ever done. Fortunately, all the elements fell together on that first day. I had the total support of the cast, crew and company to go ahead and do the best job possible. The cast was, and has always been, totally supportive of working with and for me, and I can't say enough about their cooperation."

_{^{Les Landua - Episode Director; (The Official Star Trek: The Next Generation Magazine Vol. 21, p. 41}}

Any failings in the episode can be ascribed to a lack of time to tighten up the script and deal with the more obvious plot-holes.