Farthest Star

When an artifact is observed heading towards the Milky Way galaxy, the confederation of humans and alien races sends a Project Orion style nuclear powered probe to investigate it, populated by sending copies of scans of individuals by tachyon to be constructed on the probe; they labor to construct an even faster probe before they die from the stray radiation. Meanwhile on the object, a humanoid boy from one of the many resident species encounters some of the explorers transported to the surface, and together they must face attacks from another, unfamiliar species.

Fixup of the novella "Doomship" (1973) and the serial "The Org's Egg" (1974)