What limits the Galileo orbiters useful lifetime?
Propellant, power (provided by the Radioisotope Thermoelectric Generators), dollars and Jupiter’s radiation environment are the most significant factors to define the mission’s lifetime. Energetic electrons and ions (both protons and heavy ions) trapped in Jupiter’s radiation belts can cause interference and damage in electronic parts in the Galileo Orbiter. In fact, if the spacecraft kept repeating its initial 200-day orbit, the spacecraft would “die” after several passes through the system from radiation effects (or might actually drop at its low point into the atmosphere due to gravitational perturbations of the Sun). The spacecraft contains enough radiation shielding to keep any part from failing during the baseline 2 year mission. After that, the risk of spacecraft components failing increases (somewhat like an auto manufacturer’s warranty). Galileo’s budget covers two years of orbital operations. Without the support of the flight team – almost three hundred individuals that initi
