Figure 55.5 shows a very complex example of an orbit design, in which the ISEE-3 (International Sun-Earth Explorer 3) spacecraft was re-named ICE (International Cometary Explorer) and sent to intercept two comets.
Figure 58.6.1: In 1982, the International Sun/Earth Explorer 3 (ISEE-3) spacecraft was re-purposed to become the International Cometary Exporer (ICE), so that it could explore comets Giocobini-Zinner and Halley. ISEE-3 orbited the L1 Sun-Earth Lagrange point. Getting the spacecraft to intercept the two comets involved one of the most complex trajectories ever designed (shown here). (Credit: NASA.)