4 ideas
In this Soviet science-fiction story, a starship's fixed mass budget means not everyone and everything can make the voyage, so someone's survival or place aboard depends on the payload numbers. An artist on board supplies the human answer to a question the engineering can only pose. The case tests whether a hard physical limit can settle a question about the value of a human life.
When every kilogram of payload has a measurable cost in fuel and range, carrying a person becomes a line item competing with instruments and supplies. The constraint turns an ethical question into an accounting problem, which makes the choice feel objective while hiding that someone still has to decide what counts as worth its weight.
An engineering limit can fix how much can be carried and so define the set of possible outcomes. It cannot say which outcome is right, because that depends on values the calculation leaves out.
Instead of asking what the mission needs functionally, ask what those who arrive will need that no instrument supplies. Seen this way, the artist is not surplus mass but carries meaning, memory and purpose, which is what makes the journey worth making.