The Lunar Reconnaissance Orbiter (LRO) is a robotic spacecraft launched by NASA on the 18th of June, 2009. It orbits the Moon in a low polar orbit, a mere 50 km above the lunar surface, and is considered to be a precursor to future manned missions to our nearest neighbour in space. From the LRO’s detailed photographic record NASA hopes, amongst others, to locate safe landing sites, identify potential resources and characterize the radiation environment at likely landing sites. The cost of the LRO mission is around $500 million.
A recent image of a crater triplet, that has been named “Tres Amicis” (Latin “three friends”) is particularly interesting. In the first place the three craters are all about the same size – from left to right 180, 150, and 125 meters across. Secondly they are very close together because the group only spans a total distance of about 450 meters, leading one to assume that the impacts are related. Go here see all the images and read the article on Bad Astronomy.