Poul Anderson's The Enemy Stars: This was serialized as "We Have Fed Our Sea" in Astounding, and was nominated for a Hugo award in 1959. In a generations-long project, the Southern Cross was launched to the farthest reaches of space, carrying one end of a matter-transmitter, in a mission to expand humanity's reach to the ends of the Galaxy. 10 generations out, the transmitter fails, leaving the crew in danger for their lives unless it can be fixed somehow.