Eye of the Needle
This graphic shows how navigators steering NASA's Mars Science Laboratory capsule — with the Curiosity rover tucked inside — are aiming for a pinpoint location above Mars. They liken it to threading the eye of a needle.
Navigators are aiming for a point inside of a target box that is 1.7 by 7.15 miles (2.8 by 11.5 kilometers) wide above the Red Planet. Mars' gravity well, which has been precisely calculated, will pull the spacecraft into the Martian atmosphere. The plane in which MSL has been traveling toward Mars — labeled trajectory plane — hits what is known as the B-plane at a 90 degree angle. The B plane is the plane perpendicular to the velocity of the spacecraft when it is far away from Mars. It is used for maneuver targeting. The northward direction of Mars' pole is also indicated.