Continuity mistake: Atmospheric pressure is inconsistent throughout the book. Grace says Erid has 29x Earth's pressure (because of the 1 ball:29 balls Rocky provides). But all Rocky can measure is the Hail Mary's pressure, and earlier Grace said it was only 40% of Earth's (Ch. 7: "the entire Hail Mary is at that 40 percent pressure"). So Erid would really be 29 x 40% = 11.6 times Earth normal. Also, the Hail Mary pressure is sometimes described as "0.33 atmospheres" (Ch. 27), or "one-fifth atmosphere" (Ch. 16).
Character mistake: Ch. 21: When Rocky tells Grace he blew the scabs off his wounds, he calls it a "black substance." But Grace never said it was black, and we know from when they get the first astrophage sample (Ch. 17) that Rocky doesn't understand "black" and "white." Even if Grace did explain what black is, offscreen so to speak, neither of them would know that Rocky's scabs later would be black. They never talked about it before (and if they had, Grace would have known not to mess with it).
Continuity mistake: After the "adventure in acceleration" at Adrian, the Hail Mary is effectively upside down (Ch. 20). Then Grace gets "sick of living in the Poseidon Adventure" and rights it-meaning the storage area is at the bottom again. He goes in there to fix a leak, then "climb[s] back down and wince[s] the whole time." He should be climbing up or out, not down. Also, in Ch. 22, when Grace is in there again (finding Taumoeba poo), "Rocky calls out from below"-but Rocky should be above him, not below.
