Trying to wrap my head around the latest episode

Maybe I missed an explanation in the episode, but how long were they in space before being ambushed? Seems like it happened not that long after they left earth. does that imply conquest was already heading back to earth, and they just so happened to be able to ambush the ship? or is the mole on the ship and gave away their location so they could be ambushed? I have my theories, but what do you think?