[throw310822]

No, the main character isn't confused at all in his last message, he's very confident in saying that the station "is coeval with the cosmos, and constitutes the cosmos." That's why the "estimated diameter: 15k ly" feel like a writer's oversight. Unless it's intentional, but then I'd like to understand why.

[mcphage]

> No, the main character isn't confused at all in his last message, he's very confident in saying that the station "is coeval with the cosmos, and constitutes the cosmos."

The main character is in the midst of a religious fervor. The station does not constitute the cosmos.

> "estimated diameter: 15k ly" feel like a writer's oversight.

Every time the instruments were checked, the instruments jumped in estimated diameter. Are you confused because the speaker got to the conclusion that the station is the universe before the instruments did? No doubt if there were more reports, it would be reported as being larger. Probably it wouldn't stop at the size of the universe, either.

In any event: neither the speaker, nor their instruments, were correct. Both are deeply confused about what the station is.

[throw310822]

The size estimates provided are not instrumental readings- there's no information in the text that supports this interpretation. They are- as it makes sense and as clearly stated- estimates based on the best knowledge and understanding of the reporter at that particular moment. They change with the physical exploration of the base. So when the reporter says that the base is the size of the cosmos, his size estimate should match the size of the cosmos. It's pretty clear that here Ballard just chose a number that seemed both immense and a big enough jump from the previous estimate, but at a second look makes his character incoherent because he's contradicting what he just wrote.

[mcphage]

> instrumental readings- there's no information in the text that supports this interpretation.

From the story: “A curious feature of the station is its powerful gravitational field, far stronger than would be suggested by its small mass. However, this probably represents a faulty reading by our instruments.”

And then the next paragraph is the estimated size.

> but at a second look makes his character incoherent because he's contradicting what he just wrote.

His character was incoherent from the first look, too.

[throw310822]

Yes, they have instruments and they ignore their readings when they appear to diverge wildly from their assumptions. (Here the mention of gravity is confusing because that's one thing you don't need an instrument to measure and that directly translates to mass- but I interpret the sentence you quoted as meaning: "our instruments read a powerful gravitational field that doesn't match with the mass reasonable for a 500 metres station, so it's probably a faulty reading").

In any case, the following report clarifies:

"To our surprise we find that the station is far larger than we guessed. [...] This fine vapour obscured the substantial bulk of the station and led us to assume that it was no more than a few hundred metres in diameter."

So the reporter refers to his previous estimate as a guess, not a measurement, and specifies that the assumption was based on what they could see. The following estimates are similarly guesses based on their current understanding and explorations, not the output of some specific instrument.

[Jtsummers]

The report writer also failed to realize they'd looped back to their starting location until much after they had done so. They're clearly unreliable, an inconsistency like that doesn't need to be explained by anything other than that the author is losing their grip on reality. The other explanation is that their instruments are indicating a diameter of 15,000 light years and that that is all they are recording (as they were recording in previous reports, the numbers came from instruments), and the report writer has failed to recognize the inconsistency between their belief and the facts available to them.