Approach

The approach phase began two months prior to Mars orbit insertion.

Three primary activities occurred during this phase:

• navigation measurements to determine the position and trajectory of the orbiter

• preparations for final trajectory correction maneuvers (TCM-4 and TCM-5) that ultimately were not needed because of the remarkable accuracy of the spacecraft's path

• an engineering test called the Optical Navigation Experiment..

To learn what form the spacecraft took during this mission phase, see the spacecraft's approach configuration.