Olympus. Talosian Chronicles, #1

Over four-thousand years ago, a starship crashed on the dark side of the moon. Acting on its final orders, the AI began repairs, and then searched for a new crew. Finding Ian Williams, a virtual clone for its original commander, the AI contacts him and convinces him to undertake the challenge of getting the big ship back in space and protecting the Earth from the enemy that originally caused it to crash.
Can Ian do what needs to be done without any of the governments of the planet finding out about it? Will one star ship be enough to protect the planet? Will the damn thing even be able to fly again?