Epigraphs are like little appetizers to the great main dish of a story. They illuminate important aspects of the story, and they get us headed in the right direction.
All the epigraphs in the book are made up. That is, they refer to documents that are part of the sci-fi world of the book, rather than to documents out here, in the world where you Shmoop. There is no journal called Xenological Studies (2.6), nor is there a book called Letter to the Framlings (1.3). Do not Google them; do not ask your librarian; and if you do find copies, step away slowly, looking over your shoulder for mischievous sentient computers and/or Hive Queens.