Infrared space observatories: How to mitigate zodiacal dust interference

Out-of-the-ecliptic trajectories that are beneficial to space observatories such as the Terrestrial Planet Finder and other potential mid-IR missions are introduced. These novel trajectories result in a significantly reduced background noise from the zodiacal dust radiation, compared to a 1 AU in-plane orbit. Three types of trajectories are characterized using genetic algorithms. Based on the characterization process, two optimal highly inclined non-Keplerian trajectories that are energetically feasible are derived. The energy requirements to reach these trajectories are respectively half as much and equivalent to a direct trip to 5 AU with no planetary gravitational assists. We use the zodiacal dust model from the COBE data to determine how well the optimal trajectories mitigate the interference from the zodiacal dust. The first optimal trajectory can use existing launch technology and yields a maximum decrease of 67% in the zodiacal cloud brightness. The zodiacal brightness for this trajectory is reduced by at least 50% for 60% of the mission lifetime. The second optimal trajectory requires planned improvement in launch technology, but it renders a dramatic 97% maximum noise decrease. The zodiacal cloud brightness is reduced by at least 70% for 82% of the mission lifetime for this trajectory.