Analysis of trajectories to Neptune using gravity assists

At the present time the search for the knowledge of our Solar System continues to be effective. So, on July 1st, 2004, the international Cassini-Huygens Mission spacecraft entered into orbit around the planet Saturn, and at the present time (January, 2005), it is sending data from the Huygens probe which is studying Saturn's largest moon, Titan. NASA's Solar System Exploration theme listed a Neptune mission as one of its top priorities for the mid-term (2008-2013). The gravity assist is a proven technique in interplanetary exploration, as exemplified by the missions Voyager, Galileo, Cassini, etc. Here a mission to Neptune for the mid-term (2008-2020) is proposed. Based on the continuation of our previous work, the following schemes are analyzed: Earth-Jupiter-Neptune, Earth-Venus-Earth-Jupiter-Neptune, Earth-VenusEarth-Jupiter-Saturn-Neptune. All the transfers are optimized in terms of the total AV, in order to find a good compromise between the AV and time of flight to Neptune. This paper considers launch from Low Earth Orbit (LEO).