Mars Reconnaissance Orbiter Approaches Mars

NASA's Mars Reconnaisasance Orbiter is beginning its final approach to the planet today. In order to arrive in its low orbit around the planet, the spacecraft will fire its main thrusters for 27 minutes this afternoon, resulting in a decrease in speed by about 20%. In the next six months, the spacecraft will go through a process of aerobreaking, in which the spacecraft will go through 500 successive dips toward a low orbit around Mars by utilizing the friction in its atmosphere to decrease its orbit size. The primary science phase of the mission thus won't begin until November. Here is a nice animation of the aerobreaking process, and more animations available here. Image credit HubbleSite.org.