The Mars Orbiter spacecraft, built by Lockheed Martin Astronautics in Denver, is managed by the NASA Jet Propulsion Laboratory in Pasadena, Calif. The spacecraft will arrive on Mars in October 1999. Upon arrival, it will observe seasonal changes on the planet by mapping its surface for an entire Martian year (687 Earth days). The probe will examine the Martian climate and the presence of usable resources, and look for evidence of past life. The mission also will provide an on-orbit data relay for the Mars Polar Lander mission, which will be launched aboard a Delta rocket in January 1999. Additionally, the mission aims to establish the capability for future U.S. and international surface stations.

The probe is the 76th scientific mission to fly on a Delta rocket since 1961. Overall, the Delta program boasts a better than 98 percent success rate for scientific missions.