LADEE impact crater found

LADEE impact site on the eastern rim of Sundman V crater, the spacecraft was heading west when it impacted the surface. The image was created by ratioing two images, one taken before the impact and another after the impact. The bright area shows the impact point and the ejecta (things that have changed between the time of the two images). The ejecta form a V shaped pattern extending to the northwest from the impact point. Ratio constructed with LROC images M1163066820RE and M1101816767RE [NASA/GSFC/Arizona State University].

Mark Robinson
Principal Investigator
Lunar Reconnaissance Orbiter Camera (LROC)
Arizona State University

The Lunar Atmosphere and Dust Environment Explorer (LADEE) was launched from Wallops Island on 6 September 2013 at 11:27 EDT and was visible over much of the eastern coast of the United States. The spacecraft was 2.37 m (7.8 ft) high and 1.85 m (6.1 ft) wide with a mass of 383 kg (844 lb) including the fuel.

After expending most of its fuel during its successful exploration of the Moon the spacecraft had a mass of about only 248 kg (547 lb) when it impacted the surface.

Artist's rendition of the LADEE spacecraft in orbit around the Moon [NASA/JAXA/LP].

Originally LADEE was placed into a retrograde, near-equatorial orbit to study the Moon's surface bound exosphere and dust environment. Since the Apollo era of exploration several conflicting ideas and observations concerning the existence (or not) of near-surface and high altitude dust were debated, and thus one of LADEE’s key science goals was to search for dust particles high above the surface (no dust was found).

LADEE's engines were fired on 11 April 2014 to adjust the orbit in such a way as to guarantee a farside impact if the spacecraft did not survive the 15 April 2014 eclipse. There was a small worry that if the spacecraft failed during the eclipse and was uncontrollable, it might impact near one of the Apollo sites. Over the subsequent 7 days, the low point in LADEE's orbit decreased resulting in an impact on 18 April 2014.

Before and after images of the LADEE impact site [NASA/GSFC/Arizona State University].

As it passed over the western limb as seen from the Earth, the spacecraft impacted the eastern rim of Sundman V crater (11.85°N, 266.75°E). The impact site (11.8494°N, 266.7507°E) is about 780 m from the crater rim with an altitude of about 2590 m, and was only about 295 meters north of its originally predicted location (based on tracking data).

Like the LADEE spacecraft, the impact crater is small, greater than 3 meters in diameter, barely resolvable by the LROC NAC. Based on impact models, a crater of only about 1.8 m (6 ft) diameter is expected. The crater is very small because, as impacts go, LADEE had a low mass and a low density (0.43 g / cm3 vs. larger than 3.0 g / cm3 for an ordinary chondrite meteorite), and was traveling at only a tenth the speed (1699 m/sec - 3800 mph) of an average asteroid.

LADEE impact crater (centered of image) has a distinctive hour-glass albedo pattern indicative of low angle impacts. Bright material extends to the northwest, while only a minor amount was ejected to the southeast; NAC M1163066820RE [NASA/GSFC/Arizona State University].

Because it is so small, the crater is hard to identify among the myriad of small fresh craters that dot the lunar surface. However, as images had been acquired of the impact region before the impact occurred, they could be compared with images acquired after the impact to identify the crater.

Since NAC images are so large (250 megapixels) and the new crater is so small the LROC team coregistered the before and after images (called a temporal pair) and then divided the after image by the before image. In this manner any changes to the surface stick out like a beacon! For the LADEE crater the ejecta forms a triangular pattern primarily downrange (to the west) extending more than 200 meters from the impact site. There is also a small triangular area of ejecta uprange but it extends only about 20-30 meters. The ejecta pattern is oriented WNW consistent with the direction the spacecraft was traveling when it impacted.

Zoomed-in view of the impact site, image is 200 m across, NAC M1163066820RE [NASA/GSFC/Arizona State University].

Explore the catalog of LROC close-ups of lunar spacecraft landing and impact sites, HERE.

Related LADEE Posts:
First Science from LADEE (45th LPSC, March 18 2014)
LADEE's (star tracker) images of the Moon (February 14, 2014)
LADEE economy adds 28 days to mission (February 5, 2014)
LROC captures LADEE from 9,000 meters (January 30, 2014)
Red Moon, Blue Moon Dwayne Day, The Space Review (December 3, 2013)
LADEE begins collecting data (November 22, 2013)
LADEE transitioning out of commissioning phase (November 6, 2013)
Apollo 12 ALSEP first to measure dust accumulation (November 21, 2013)
Chang'e-3 & LADEE: The Role of Serendipity (October 31, 2013)
LADEE LLCD sets new data record (October 25, 2013)
Measuring almost nothing, looking for the almost invisible (October 16, 2013)
LADEE legacies (September 7, 2013)
LADEE Prelaunch Mission Briefing (September 6, 2013)
ESA prepares for LADEE (July 31, 2013)
LADEE arrives at Wallops Island (June 5, 2013)
LADEE ready to baseline dusty lunar exosphere (June 5, 2013)
First laser comm system ready for launch on LADEE (March 16, 2013)
LADEE project manager update (February 6, 2013)
The Mona Lisa test for LADEE communications (January 21, 2013)
Toxicity of lunar dust (July 2, 2012)
Expectations for the LADEE LDEX (March 23, 2012)
The Dust Management Project (August 9, 2010)
LADEE architecture and mission design (July 6, 2010)
DesertRatS testing electrodynamic dust shield (July 5, 2010)
Dust transport and its importance in the origin of lunar swirls (February 21, 2010)
Dust accumulation on Apollo laser reflectors may indicate a surprisingly fast and
more dynamic lunar exosphere (February 16, 2010)
NASA applies low cost lessons to LADEE (January 18, 2010)
Nanotech advances in lunar dust mitigation (August 19, 2009)
Moon dust hazard influenced by Sun's elevation (April 17, 2009)
LADEE launch by Orbital from Wallops Island (April 14, 2009)
Understanding the activation and solution properties of lunar dust
for future lunar habitation (March 2, 2009)
Respiratory toxicity of lunar highland dust (January 19, 2009)
Toxicological effects of moon dust (June 25, 2008)
Moon dust and duct tape (April 22, 2008)