Messenger is expected to hit the surface of Mercury on march 30 . Probe has been observing Mercury since 2011 , using infrared pictures . Latest imagery shows features such as volcanic rocks and fresh craters .
Messenger is expected to hit the surface of Mercury on April 30 . Probe has been orbiting Mercury since 2011 , taking 250,000 pictures . Latest image shows features such as volcanic vents and fresh craters .