PIA16545: Chain Reaction

Chain Reaction


This image, taken with the Wide Angle Camera (WAC), shows several secondary crater chains . These features are formed when ejecta from a primary impact is thrown outward. As the pieces fall back to the surface, they can form chains of small secondary craters. In this particular case, the primary impact was most likely the one that formed Abedin crater. With the Sun just 3° above the horizon (incidence angle = 87°), the craters are filled with shadow.

This image was acquired as part of MDIS's high-incidence-angle base map. The high-incidence-angle base map is a major mapping activity in MESSENGER's extended mission and complements the surface morphology base map of MESSENGER's primary mission that was acquired under generally more moderate incidence angles. High incidence angles, achieved when the Sun is near the horizon, result in long shadows that accentuate the small-scale topography of geologic features. The high-incidence-angle base map is being acquired with an average resolution of 200 meters/pixel.

Date acquired: October 07, 2012
Image Mission Elapsed Time (MET): 258083386
Image ID: 2719301
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filter: 7 (748 nanometers)
Center Latitude: 66.31°
Center Longitude: 356.2° E
Resolution: 162 meters/pixel
Scale: This image is about 83 km (51.5 miles) across.
Incidence Angle: 87.3°
Emission Angle: 3.7°
Phase Angle: 91.0°

Background Info:

The MESSENGER spacecraft is the first ever to orbit the planet Mercury, and the spacecraft's seven scientific instruments and radio science investigation are unraveling the history and evolution of the Solar System's innermost planet. Visit the Why Mercury? section of this website to learn more about the key science questions that the MESSENGER mission is addressing. During the one-year primary mission, MDIS acquired 88,746 images and extensive other data sets. MESSENGER is now in a year-long extended mission, during which plans call for the acquisition of more than 80,000 additional images to support MESSENGER's science goals.

These images are from MESSENGER, a NASA Discovery mission to conduct the first orbital study of the innermost planet, Mercury. For information regarding the use of images, see the MESSENGER image use policy .

Cataloging Keywords:

Name Value Additional Values
Target Mercury
Target Type Planet
Instrument Host MESSENGER
Host Type Orbiter
Instrument Mercury Dual Imaging System (MDIS)
Detector Wide Angle Camera (WAC)
Extra Keywords Crater, Grayscale, Impact, Map, Radio, Shadow
Acquisition Date
Release Date 2012-11-21
Date in Caption 2012-10-07
Image Credit NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Source photojournal.jpl.nasa.gov/catalog/PIA16545
Identifier PIA16545