posted by keitanako .
A possible trajectory for sending a spacecraft to Mars is an elliptical orbit with Earth at its perihelion and Mars at its aphelion. The craft would be launched out of low-Earth orbit by a quick burst of rockets into solar orbit, and would then "coast'' until rockets fire again to match its speed to that of Mars and lower it into an orbit about the planet. Neglecting the acceleration and deceleration phases, how long would it take to get from low-Earth orbit to Mars along this "minimal-energy'' trajectory?
Express your answer in years.