Mars Science Laboratory's parachute, used to slow the spacecraft down during entry, descent, and landing, is part of a long-term Mars parachute technology development effort. It inherits much from its martian predecessors, the Viking, Pathfinder, and Mars Exploration Rover missions.
Parachute designs are driven by "loads" (the forces the parachute experiences as it fully inflates). Loads are calculated by using atmospheric density, velocity, parachute drag area, and mass. For the exponentially heavier Mars Science Laboratory mission, the parachute's basic design remained the same, but is about 10 percent larger in area than the one used for the Mars Exploration Rover mission. By comparison, that mission was 40% larger than Pathfinder's parachute.
The ability to land large payloads safely on the surface of Mars enables increasingly sophisticated robotic missions, and might also help pave the way for emplacing the infrastructure that would be needed to support human missions to Mars someday.