Besides the amazing science and engineering that has gone into the missions to Mars, a touch down on the planet's surface is also a geographic problem.
Geography will always play a key role in deciding where.

On May 25, 2008, NASA's Mars Phoenix Lander parachuted to a safe landing in the north polar region of Mars.

In January 2004 the NASA rovers, Spirit and Opportunity, began exploration and data gathering on nearly opposite sides of Mars. The importance of planetary geography and the geographic characteristics of the study locations have been clear in the NOVA specials, MARS: Dead or Alive (2004) and Welcome to Mars (2005) which aired on PBS.

Factors of mission success (safety and scientific merit) for the rovers translated into the geography of Gusev Crater (Spirit landing site) and Terra Meridiani (Opportunity landing site). Selection criteria of these sites included

• Adequate solar radiation to power the rovers (equatorial location)
• Maximum parachute performance and crash avoidance in the thin atmosphere (low elevations)
• Safe landing locations (minimal slope and minimal known geological hazards)
• Finding indicators of life (probable former water areas including Gusev Crater
• Favorable surface geology (presence of hematite in Terra Meridiani)

There is much of Mars to explore and understand.