Having read through this, I have to disagree with a lot of the comments here. This story really feels copy and paste to me. The fact that the probe is based on Twilight's personality is purely coincidental to the story as a whole. There's nothing offered as to why it would need to specifically be Twilight's personality the probe's AI is modeled after and the parts where it's not musing on its existence and purpose are just technobabble. In fact, you could easily change the personality basis for Celestia or Sunset Shimmer and it'd have zero impact on the plot of this story.

There's literally one line here that tries to have the audience build a connection to the probe by feeling sorry for it and that line is it just telling us that it has Twilight's memories, hopes, and fears. That's not really me feeling bad for the probe though, that's more me imagining Twilight in isolation than relating to what this particular space probe is going through. Honestly, the story comes off as a feels grab and I think it feel flat for me for that reason.

I can't really see the connection to the prompt here, either. The Twilight Zone show has some science fiction elements, but it lacks the tone for that. If we're going for the more colloquial definition of where something ends and another begins, but we're really stretching for that one.

While an interesting idea in theory, the whole implanting memories and personality into an AI and learning how it would cope with that, I can't say this does a good job at conveying its premise in its short word count. I guess just some food for thought, ask why Twilight is the basis for this AI, and what that is uniquely offering to this story.