March 29, 2011
Image Mission Elapsed Time (MET):
Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
This image is 390 kilometers (240 miles) across
This image of a number of unnamed craters was taken with MESSENGER's Narrow Angle Camera (NAC), one of the two cameras that make up the Mercury Dual Imaging System (MDIS). The NAC is an off-axis reflector telescope with a focal length of 550 mm, a field of view of 1.5°, and a collecting area of 462 mm2
. The detector located on the focal plane is a 1024 × 1024 pixel (1 megapixel) CCD. The NAC takes monochromatic images using a single medium-band filter, unlike the Wide Angle Camera
, or WAC, which can view the planet through one of 11 different spectral filters or a broadband filter.
This image was taken using MDIS's pivot. MDIS is mounted on a pivoting platform and is the only instrument in MESSENGER's payload capable of movement independent of the spacecraft. The other instruments are fixed in place, and most point down the spacecraft's boresight at all times, relying solely on the guidance and control system for pointing. The 90° range of motion of the pivot gives MDIS a much-needed extra degree of freedom, allowing MDIS to image the planet's surface at times when spacecraft geometry would normally prevent it from doing so. The pivot also gives MDIS additional imaging opportunities by allowing it to view more of the surface than just that at which the boresight-aligned instruments are pointed at any given time.
On March 17, 2011 (March 18, 2011, UTC), MESSENGER became the first spacecraft ever to orbit the planet Mercury
. The mission is currently in the commissioning phase, during which spacecraft and instrument performance are verified through a series of specially designed checkout activities. In the course of the one-year primary mission, the spacecraft's seven scientific instruments and radio science investigation
will unravel the history and evolution of the Solar System's innermost planet. Visit the Why Mercury?
section of this website to learn more about the science questions that the MESSENGER mission has set out to answer.
Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
For information regarding the use of MESSENGER images, see the image use policy.