Chindi — Jack McDevitt

The universe has been explored--and humanity has all but given up on finding other intelligent life. Then an alien satellite orbiting a distant star sends out an unreadable signal. Is it the final programmed gasp of an ancient, long-dead race? Or the first greeting of an undiscovered life form? Academy starship captain Priscilla Hutchins and the once-maligned Contact Society are about to learn the answers...to more questions than they could possibly conceive of asking.