Heaven's War (Heaven's Shadow)

The competing teams of astronauts sent to explore the asteroid Keanu discovered it was, in fact, a giant spacecraft with an alien crew carrying a plea for help. A brave new frontier beckons. But it will come at a price. Without warning, the aliens transport small groups of humans to the vast interior habitats of Keanu.
 
Their first challenge is to survive. Their second: discover why The Architects—the unseen aliens controlling the asteroid—brought them there. The third: find a way to take control of Keanu. Because the ship is moving again.    
             
The Architects are going home...