Mars Global Surveyor. Artist's impression of the Mars Global Surveyor (MGS) spacecraft in orbit around the 'red planet'. After launch in November 1996, MGS will cruise on a direct trajectory to Mars, then enter a highly elliptical orbit. It will then use 'aerobraking' (dipping into the upper atmosphere on each pass) to slow down and to circularise the orbit. By March 1998 it will start a two-year mapping and observation mission. One of its cameras will resolve details just 3 metres across. MGS will perform five of the seven tasks assigned to the defunct Mars Observer mission, and will act as a radio relay for Russian and US landers.