The Starchild Compact - Robert G. Williscroft

The Starchild Compact is an epic tale of beginnings, of roots, of what might have been, and what might be. The Starchild Compact is an adventure of heroic pro- portions, commencing on a planet 500 light years distant, arriving here just a few years from now, and ending up in the far distant expanses of the Universe. 

Jon Stock takes his exploration team to Saturn's moon, Iapetus, that Earth scientists have determined may be an artifact. Following launch, they discover Saeed Ismail, a Jihadist stowaway, who hopes to sabotage the mission.  

They arrive at Iapetus, determine it is a derelict starship, and eventually meet with the Founders, descendants of the starship builders. Their revelations impact the entire Solar System with momentous implications going backward and forward in time, paving the way for a joint push to the distant reaches of the Galaxy.