Across the Sea of Suns(1984)

Gregory Benford

In 2021, radio astronomy on the Moon reveals the presence of life by a nearby red dwarf, on a tide-locked planet.[1] To investigate, Earth's governments convert a space colony into Lancer, a Bussard ramjet powered interstellar ship based on the design of a crashed alien ship discovered in the Mare Marginis. In 2061, it arrives and discovers a primitive race of nomads, broadcasting using organs adapted to emit and receive electromagnetic radiation. A curious satellite is discovered in orbit, at least a million years old, roughly when a meteor shower destroyed the EMs' civilization.