The first fly-by of Mercury by a probe from Earth in 33 years took place in January this year [plenty of images and videos there], before departing the planet on January 14, and on Monday morning NASA’s Messenger probe, is due to return to Mercury for its second fly-by of the closest planet to the Sun. The planet is already clearly visible from the probe and the animation below details the measurements that will be taken this time. The Messenger flyby 2 page will update as more information becomes available. Messenger has already visited Venus twice and there’s one more flyby of Mercury scheduled for September 2009 ahead of a year-long orbital mission, which begins in March 2011. (All images credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington).