TAU: a design for a thousand astronomical unit voyage

The Jet Propulsion Lab. (JPL) has proposed a deep-space probe to travel to a distance of one thousand astronomical units -25 times further from the Sun than Pluto. In order to achieve this goal within the lifetime of the investigators, the mission time is set at a maximum of 50 yr. The JPL proposal postulates a design in which the probe is under powered thrust for the first 10 yr of the mission and coasts for the next 40 yr. A continuous high specific impulse, Isp (the ratio of thrust to propellant mass flow rate), low thrust propulsion system (either magnetoplasmadynamic (MPD) or ion thrusters) is required in order to achieve this goal. This in turn necessitates electrical power in the megawatt range. The only power source that is practical for this situation is a nuclear reactor. It was a this point that the Nuclear Engineering Dept. at Texas A and M Univ. began its ongoing work, looking into several areas of the proposal in which a more detailed description was needed. These areas of interest were power, propulsion, heavy lift launch capabilities, and trajectory analysis. In addition to all of the boundaries previously outlined, the technology level is assumedmore » to be that of 1995, 8 yr from now.« less