Evaluation of Existing Electric Propulsion Systems for the OSIRIS-REx Mission

A study was conducted to evaluate the ability of eight existing ion and Hall thrusters to meet some of the key requirements of the OSIRIS-REx mission. The calculations in this study were done with a two-body, coplanar orbit assumption. This study was conducted with a fixed landing date and did not specifically estimate the shortest trip possible. It was also assumed that the thrusters always operated at full power and did not consider throttling or turning off the thruster to reduce fuel requirement. The study revealed that all those thrusters, at their demonstrated performance levels, are able to carry a dry mass of 750 kg to the asteroid 1999RQ36, land on it in 2019, stay for 219 days, and return it with a 10 kg sample to Earth. The fuel fraction required at low Earth orbit varied from 27 30% for HiPEP to 65 70% for others. It was shown that all the evaluated thrusters could complete the mission in significantly less time of the OSIRIS-REx mission, and still remain within the mass requirements of conventional launchers considered for the mission.