Orphans -- Juvenile fiction. Robots -- Juvenile fiction. Rockets (Aeronautics) -- Juvenile fiction. Extraterrestrial beings -- Juvenile fiction. Human-alien encounters -- Juvenile fiction.

Space ships -- Juvenile fiction. Human-alien encounters -- Juvenile fiction. Unidentified flying objects -- Sightings and encounters -- Juvenile fiction. Space flight -- Juvenile fiction. Families -- Juvenile fiction.

Life on other planets -- Juvenile literature Human-alien encounters -- Juvenile literature