Evaluation of Fuel-efficient Sun Search Slew Rates for the Cassini Spacecraft in the Cassini Solstice Mission

摘要

As NASA's Cassini spacecraft continues to explore the Saturnian system in the second extended mission named the Solstice mission, the spacecraft operators have increased efforts to minimize hydrazine consumption to ensure the mission's success through the end of the Solstice mission scheduled in mid-September 2017. In this paper, fuel-efficient slew rates are evaluated for the Cassini Sun search. Ground simulations show that hydrazine consumption could be significant during Sun search in the extreme cases, possibly bringing the Solstice mission to a premature end. A mathematical model for hydrazine consumption during Sun search is derived and the effects of varying slew rates on hydrazine consumption are explored. Slew rate constraints are presented, and an optimal set of slewing rates is chosen that minimizes hydrazine consumption. Simulation results show that fuel-efficient slew rates offer a saving of over 45% in hydrazine consumption compared to the default slew rates.