Improved Tour-Map graphical method for gravity-assist

The analysis of gravity-assist effects is of great importance on the design stage to specify both the swingby sequence and the initial parameters. An improved Tour-Map graphical method for this purpose was introduced, which permits a quick identification of key parameters in ballistic gravity-assist. By the patched conic assumption, the graphical method was developed according to the geometric relationship of excess velocity and the position and velocity of the gravity-assist planet, followed by analytical developments of key heliocentric orbit elements after swingby, such as period, inclination and eccentricity. Then the complicated requirements of gravity-assist was described as contours on two dimensional Tour-Map conveniently. A design example of high-inclination solar orbit with Jupiter assist was included to illustrate the usage.