Felt a bit awkward making Arut refer to Tama as it, but there's nothing gendered in Japanese I can defer to, and when she's not even sure whether Tama is a mammal it'd be strange if she knew she was a girl. Sometimes there are no good solutions.
Truly one of the greatest cliches for far flung future settings: Technology outliving Mankind. Very odd for an artificial intelligence to be unable to recall or recognize the appearance of it's masters, though.