It will take seven months for Spirit and Opportunity to reach Mars.
During that time, health checks will be performed on each spacecraft, as
well as trajectory correction maneuvers, and communication tests for the
entry, descent and landing phase of the mission. Spirit will land at
Gusev Crater on January 3, 2004 and Opportunity will touch down at
Meridiani Planum on January 25, 2004. You can follow the progress of
the spacecraft, and the movement of Earth and Mars in their orbits by
using the graphic below. Sol 90 (a sol is one martian day or 24.6 earth
hours) is when the primary mission is expected to end.