The Mars Reconnaissance Orbiter (MRO) spacecraft reached Mars on 10 March 2006 and was inserted into a highly elliptical Mars capture orbit with an orbital period of 35 hours and a periapsis altitude of 426 km. Aerobraking through the Mars atmosphere was used, along with propulsive maneuvers, to transfer the spacecraft into the final low, near circular, sun-synchronous Primary Science Orbit. This paper describes the orbit determination performed during the MRO aerobraking phase for generating reconstructed and predicted trajectories. The predicted trajectories had several constraints on their accuracies, including spacecraft safety, sequence design and collision avoidance with other spacecraft. In order to meet the constraints, the atmospheric density was estimated for each aerobraking orbit. The estimated densities were analyzed and used to generate improved short-term predict models. The aerobraking similarities and differences between MRO and Mars Global Surveyor and Odyssey will be discussed.
