Chindi (The Academy, #3)

On a routine survey mission studying a neutron star, an Academy starship receives a transmission in an unknown language. Before leaving the area, the starship launches a series of satellites to find the signal and perhaps discover its origins.
Five years later, a satellite finally encounters the signal which is believed to be of extraterrestrial origin by the Contact Society, a wealthy group of enthusiasts who fund research into the existence of alien life. Providing a starship to the Academy to be piloted by Captain Priscilla Hutch Hutchins, the Contact Society embarks on a mission to find the source of the transmission.
Across a myriad of stars, from world to world, Hutch and her crew follow the signal, but find only puzzles and lethal surprises.

Then, in a planetary system far beyond the bounds of previous exploration, they discover an object. It is immense, ominous, and mysterious. And it may hold the answer not only to the questions of the Contact Society, but to those of every person who has ever looked to the sky and wondered if we were alone..."