Upon arrival, Mars Global Surveyor will be inserted into a very elliptical capture orbit. Over the next four months, a combination of aerobraking maneuvers and rocket firings will slow the spacecraft and adjust its orbit. The goal is an orbit that closely matches the one originally planned for Mars Observer-- a polar orbit crossing the equator around 2 p.m. on the day side and 2 a.m. on the night side.
Aerobraking is a technique which uses atmospheric drag to slow the spacecraft. The method requires the spacecraft to dip low enough to encounter the atmosphere, but the approach must be controlled carefully so that the spacecraft does not burn up. Aerobraking will save the amount of fuel needed for the mission. This method was not to be done on Mars Observer, and has only been attempted at another planet once: Magellan did it (with success) at Venus in 1993.
The Mars Global Surveyor mission operations at the Jet Propulsion Laboratory (JPL) will be supported by NASA's Deep Space Network (DSN) and the JPL Advanced Multimission Operations System. The DSN antennas and facilities are located in Pasadena and Goldstone, California; Canberra, Australia; and Madrid, Spain. Three such facilities scattered around the Earth ensure continuous coverage of the sky. The instrument scientists remain at their home institutions, from which they can access Mars Global Surveyor data using workstations and electronic communications links. In the same way, data products returned to the JPL database from the home institution for each of the instruments will be sent electronically to other investigators at their home institutions. This will allow scientists to have ready access to science data without moving to JPL for the duration of the mission (as was common in the past). During the mapping phase, the instrument investigations will return processed science data products to the database at JPL for access by the interdisciplinary scientists and other investigation teams.