2001 Mars Odyssey Orbit Determination During Interplanetary Cruise

Abstract

On 24 October 2001 coordinated universal time, following a seven-month journey to Mars, Odyssey executed a nominal orbit insertion burn to be captured successfully into orbit around Mars. The excellent navigation performance during the interplanetary cruise resulted in arrival conditions over the north pole of Mars well within 1‐σ of the designed values. The achieved altitude above the north pole was less than 1 km away from the 300-km target altitude. Several sources of error made the orbit determination process for Odyssey challenging. The largest of these errors was caused by the periodic autonomous angular momentum desaturation events. Several navigational aids were brought forth to mitigate the error sources and improve the accuracy of Odyssey’s interplanetary cruise navigation. The most significant of these included the incorporation of very long baseline interferometry, delta-differential one-way range tracking data into the orbit determination filtering process and the placement of the spacecraft into a low-torque attitude during the final two months of interplanetary cruise. Orbit determination solution consistency was routinely evaluated through a battery of filter strategies and data combinations. The orbit determination processes and results of Mars Odyssey from launch to orbit insertion at Mars are discussed.