Q. NASA sends a satellite to another planet by placing the satellite in a Keplerian orbit (around the sun) such that the perihelion is at the radius of the Earth's orbit (1 AU) and the aphelion is at the radius of the planet's orbit. Most of the trip is just free fall in the sun's gravitational field. The small gravitational effects of Earth and the other planet, which only affect the satellite at the very beginning and end of the trip, could be neglected.
Suppose a new planet, call it Questerion, were to appear in Solar System, in a circular orbit of radius 7.20 AU. Analyse the time it would take a NASA satellite to travel from Earth to Questerion. Express the result in years.