The author analyses the genre structure of the science fiction version of the Robinsonade, on the material of the novel by the American writer R. Heinlein, Tunnel in the Sky (1955), taking into account M.M. Bakhtin's model of the genre as a "three-dimensional constructive whole". A science fiction version emerges as a transformation of the classic Robinsonade when borrowing it in the adventurous and philosophical fiction of the twentieth century. A science fiction version retains many elements of the classic. Transformation, in the first place, touches the nature of the test (the necessary element of the adventure plot). In the science fiction Robinsonade, not only the hero is tested, but also the ideas of the social structure of mankind. The conditions undergoing the test are ambiguous: on the one hand, they are similar to the terrestrial ones (this helps the heroes to survive physically), on the other hand, the conditions are fundamentally unfamiliar. Heroes are compelled to build a house and society taking into account the physical conditions that are known in practice, also taking into account those moral principles that are in demand in the new society. Thus, an "anthropological experiment" (S. Lem) is put, ie, "what makes a person a person" (N.D. Tamarchenko) is manifested. In the subject-speech structure of the science fiction Robinsonade, an important place is occupied by "geographical descriptions" having a binomial structure (any phenomenon is compared with a similar earthly one). The semantic boundary between the world of the hero and the world of the author and the reader is also ambivalent: from the internal point of view of the hero everything that is depicted really and unconditionally, from the external point of view of the reader, is impossible. The article concludes that the science fiction Robinsonade raises the global social and philosophical questions of the survival of all mankind.