For Lunar Reconnaissance Orbiter (LRO), the lunar eclipse on June 15, 2011 is likely to be the longest and darkest of its life. This matters because LRO relies on sunlight to power its systems and instruments. Although it spends half of every orbit on the night side of the Moon, each night side pass lasts only an hour. For the June 15 eclipse, LRO will be in the dark for more than twice as long.
During a previous total eclipse, LRO hibernated, turning off all of its instruments to conserve its battery power until the Moon emerged from the Earth's shadow. For the June 15 event, LRO will leave on the Diviner Lunar Radiometry Experiment. Diviner will measure the cooling of the Moon's surface during the eclipse. This unique temperature record is expected to reveal information about the roughness and composition of the swath of lunar surface visible to Diviner's sensors during the eclipse.
The visualization archived on this page shows the view of the eclipse along the axis of the Earth's shadow, with the figures of the umbra, penumbra, and lunar and solar paths in the background. This is the view typically used in eclipse diagrams like those produced by Fred Espenak for the NASA Eclipse site.
Other visualizations in this series depict the view of the eclipse