> 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.