The S.S Heart of Gold leaves the Earth on a mission to the star Vega, 25 light-years from Earth. The Heart of Gold travels at an improbably high, constant speed of 0.80c. Four years later (as measured on the Heart of Gold), the ship arrives at a way station which is only part-way to Vega. A shuttle is then launched forward at a speed of 0.60c (relative to the still-moving Heart of Gold). The shuttle is launched directly toward Vega.How long (in years) after the Heart of Gold's departure does it arrive at the way-station according to Earth observers?