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Analytic and numeric techniques are used to assess trajectory options for the Pluto Express sciencecraft for a launch early in the next decade. The constraints placed on the Pluto Express trajectory for this study are severe-total ight time to Pluto of 12 years or less using a Delta-class launch vehicle. In addition, no ybys of Earth are permitted. Suitable trajectories are found with launch windows before, near, and after the date of the baseline launch. All of these trajectories take advantage of a gravity assist with Jupiter, and all use two or three gravity assists with Venus before arriving at Jupiter. In two cases, a Mars gravity assist is used in conjunction with three Venus gravity assists. Several asteroid yby opportunities are presented for the baseline mission and for a backup trajectory, which launch in March 2001 and July 2002, respectively. For example, a yby of the asteroid Seraphina (which has a radius of 32 km) can be accommodated in the baseline mission for an additional deterministic delta-velocity of 0.12 km/s, well within the capability of the system. Nomenclature C 3 = V 2 1 , km 2 /s 2 g = standard gravitationalaccelerationon the Earth, km/s 2 I sp = speci c impulse, s m f = total injected dry mass ( nal mass), kg m i = total injected wet mass (initial mass), kg m p = propellant mass, kg m s=c = spacecraft mass (excluding propellant tanks), kg R J = radius of Jupiter r po = radius of circular parking orbit, km V V = velocity of Venus with respect to the sun, km/s V 1 = hyperbolic excess velocity vector, km/s 1V = magnitude of a change in velocity, km/s or m/s 1V NAV = navigation 1V , km/s or m/s 1V PL = deterministic postlaunch 1V , km/s 1V TPL = total postlaunch 1V , km/s ¹ E = gravitational parameter of the Earth, km 3 /s 2

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