Moon impact! NASA’s Lunar Reconnaissance Orbiter finds new craters

NASA/Goddard Space Flight Center Press Release

Planetary scientists believe that small impacts regularly bombard the Moon, but until recently, they’ve had no way to distinguish new craters from the already pockmarked lunar surface. In 2009, NASA’s Lunar Reconnaissance Orbiter (LRO) arrived at the Moon and began taking high-resolution photographs. By comparing pictures taken early in the mission with more recent images, the LRO camera team at Arizona State University has discovered more than two-dozen new impact craters — including an 18-meter-wide crater caused by a bright flash on March 17th, 2013. Image credit: NASA (simulation)
Planetary scientists believe that small impacts regularly bombard the Moon, but until recently, they’ve had no way to distinguish new craters from the already pockmarked lunar surface. In 2009, NASA’s Lunar Reconnaissance Orbiter (LRO) arrived at the Moon and began taking high-resolution photographs. By comparing pictures taken early in the mission with more recent images, the LRO camera team at Arizona State University has discovered more than two-dozen new impact craters — including an 18-meter-wide crater caused by a bright flash on March 17th, 2013. Image credit: NASA (simulation)
NASA’s Lunar Reconnaissance Orbiter (LRO) acquired images of the lunar surface before and after the largest recorded explosion occurred on the surface. On March 17th, 2013, an object the size of a small boulder hit the surface in Mare Imbrium and exploded in a flash of light nearly 10 times as bright as anything ever recorded before.

This bright flash was recorded by researchers at NASA’s Marshall Space Flight Center in Huntsville with coordinates 20.6°N, 336.1°E. The Lunar Reconnaissance Camera (LROC) scientists were able to obtain observations before and after the impact. Comparing the actual size of the crater to the brightness of the flash helps validate impact models.

LROC’s first set of post-impact flash images acquired on May 21th, 2013 by the Narrow Angle Camera (NAC) were targeted on the Marshall-reported coordinates and numerous small surface disturbances (“splotches”) were detected by comparing the pre- and post-flash images, but no new crater was found.

A second set of NAC images was acquired on July 1st, 2013, showing three faint ray-like features and several chains of splotches and asymmetric splotches that generally pointed to a common area west of the Marshall coordinates. A NAC pair was targeted on that convergence point for July 28, 2013; comparison of this third set of images with preexisting coverage revealed a new crater.

This animation shows a lunar impact crater created on March 17th, 2013. The two images are from the LROC instrument aboard NASA's Lunar Reconnaissance Orbiter. The before image is from February 12th, 2012, and the after image is from July 28th, 2013. The new crater is about 19 metres (62 feet) wide. Image credit: NASA/Goddard Space Flight Center/Arizona State University
This animation shows a lunar impact crater created on March 17th, 2013. The two images are from the LROC instrument aboard NASA’s Lunar Reconnaissance Orbiter. The before image is from February 12th, 2012, and the after image is from July 28th, 2013. The new crater is about 19 metres (62 feet) wide. Image credit: NASA/Goddard Space Flight Center/Arizona State University
The crater itself is small, measuring 18.8 metres (61.7 feet) in diameter, but its influence large; debris excavated by the sudden release of energy flew for hundreds of metres. More than 200 related surficial changes up to 30 kilometres (19 miles) away were noted.

The results were published in the January 31st edition of the journal Icarus.

The March 17th impact crater is one of thousands of craters being mapped by the instrument. The LROC team is going back to images taken in the first year or two and comparing them to recent images. Called temporal pairs, these before/after images enable the search for a range of surface changes, including new impact craters, formed between the time the first and second image were acquired.

As of January 1st, 2015, LROC has acquired about 10,000 before and after image pairs.

Launched on June 18th, 2009, LRO has collected a treasure trove of data with its seven powerful instruments, making an invaluable contribution to our knowledge about the moon. LRO is managed by NASA’s Goddard Space Flight Center in Greenbelt, Maryland, for the Science Mission Directorate at NASA Headquarters in Washington.