LRO Observations

Eclipse Science and Observations by the Lunar Reconnaissance Orbiter

NASA’s Lunar Reconnaissance Orbiter (LRO) has been revolutionizing our understanding of the Moon since 2009. LRO has cameras that could see you if you were walking around on the lunar surface, a radiation detector that is investigating how the space environment would affect your body if you visited the Moon, an altimeter that has determined the shape of the Moon better than any other object in the Solar System – including the Earth, instruments that can “see” in the dark and below the surface and help us find water, an instrument that senses the temperatures of the lunar surface – and has measured the coldest surface in the Solar System. Every day, this spacecraft is helping us better understand our nearest celestial neighbor, and processes that act throughout the Solar System.LRO Spacecraft

LRO collects global datasets, with particular emphasis on the Moon’s polar regions, where it may be possible to access continuous solar illumination and water ice. LRO was designed to support extending human presence in the solar system. Its seven instruments help scientists identify sites close to potential resources with high scientific value, favorable terrain, and the environment necessary for safe future robotic and human lunar missions. LRO’s datasets are helping the world develop a deeper understanding of the lunar environment, paving the way for a safe human return to the Moon and for future human exploration of our solar system.


Eclipse Science


To LRO, lunar eclipses (when the Sun, Earth, and Moon align and the shadow of the Earth falls on the Moon) are the most exciting. Lunar eclipses present challenges and science opportunities. LRO is solar powered. During a lunar eclipse, LRO loses access to its source of power, so LRO’s operations team shuts down most of its instruments for the duration of the lunar eclipse to conserve energy. The exception to this is Diviner, LRO’s lunar radiometer.

Diviner measures both the reflective energy off the surface of the Moon and infrared emissions that indicate the temperature at the surface. As the Moon, and by extension LRO, passes into Earth’s shadow during a lunar eclipse, the temperature drops rapidly – nearly 280 degrees Fahrenheit (138 degrees Celsius), in minutes as the sunlight disappears. The rapid cooling during an eclipse is different than a normal lunar night, revealing information about the top few centimeters of the surface. Since LRO can only collect a narrow band of data in each orbit, each eclipse allows scientists to learn more about the Moon.

Solar Eclipse Observations

May 2012 solar eclipse
Credit: NASA/LRO

An image of the May 2012 solar eclipse captured by NASA’s Lunar Reconnaissance Orbiter Camera. The Moon’s shadow is seen passing over the Aleutian Islands. Annotated NAC Image E192199689L. Credit: NASA/GSFC/Arizona State University.

LRO’s Lunar Orbiter Laser Altimeter (LOLA) has helped us determine the shape of the Moon better than any other object in the Solar System – including the Earth. Knowing the topography of the Moon in such precise detail is important to solar eclipses in two ways: it helps us determine the roughness of the edges of the eclipse path across the surface of the Earth, as well as the locations and durations of Baily’s beads (places where beads of sunlight can shine over low points of the rugged lunar limb during a solar eclipse).

Because solar eclipses do not affect the health or power supply of the spacecraft, LRO can operate normally during the 2017 total solar eclipse. The LRO Camera captured the above image of the shadow of the Moon on the Earth during the May 2012 solar eclipse. The team plans to take an image of the Moon’s shadow moving across the United States during the August 2017 total solar eclipse. A new image processing capability, used on LRO’s recent image of the Earth, below, may allow the team to release the planned 2017 eclipse image in color.

Eclipse from the moon
Credit: NASA/GSFC/Arizona State University

Additional Resources:

A gallery animations, visualizations, and eclipse-related content compiled for the 2015 Supermoon Lunar Eclipse from NASA’s Scientific Visualization Studio

NASA’s Lunar Reconnaissance Orbiter’s Dance with Eclipses