Propulsion Jon Lewis Mike Rhee 8/19/99 MAXIM Propulsion Jon Lewis Mike Rhee 8/19/99

Stationkeeping and Pointing Control Hydrazine thrusters used as much as possible Initial S/C separation DV ~ 0.09 m/s (grams) Slew to new target (10º) requires a few kg each time (150 times) 10º change approximated by making detector S/C lag orbit S/C by prescribed distance and in a reasonable amount of time Finer control will require different propulsion device Short term acceleration requires constant mN thrust, minimal propulsion mass, may be accomplished with pulsing of hydrazine, possible use ion engine or PPT Longer term effects and fine control will utilize mN thrusters with good precision, will involve creative schemes with flight dynamics and attitude control, as well as compromise with science

Future Considerations Separation/Slew fairly well defined and understood Fine control will require several design considerations Knowledge of position, drift rates Accuracy and precision of mN thruster Contamination and EMI Integration with science duty cycles, power availability and overall mission requirements