Click on image for larger annotated version
About 69 minutes after MESSENGER’s closest approach to Mercury during the
mission’s second flyby, the NAC acquired this image of a portion of
Mercury’s surface also seen during the Mariner 10 mission. Toward the
lower portion of the image, Arecibo Vallis is visible. Vallis is the Latin
word for valley, and valles (the plural of vallis) on Mercury are named
for radio telescope observatories. Arecibo Observatory is located in
Puerto Rico and has been used to conduct Earth-based studies of Mercury
with important results, including the detection of radar-bright
materials at Mercury’s poles that may be water ice trapped in permanently
shadowed craters. Arecibo also observed some bright, rayed craters that
have now been better resolved by MESSENGER’s latest images (PIA11356). Lately,
Arecibo’s unique radar capabilities have been threatened with
closure due to changed funding priorities. The craters Ibsen (named for
the Norwegian playwright) and Petrarch (named for the Italian poet) are
also visible in this image. Bright rays from Kuiper crater extend down
from the top of the image (PIA11355).
Date Acquired: October 6, 2008
Image Mission Elapsed Time (MET): 131773984
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Resolution: 530 meters/pixel (0.33 miles/pixel)
Scale: Ibsen crater is 159 kilometers in diameter (99 miles)
Spacecraft Altitude: 21,000 kilometers (13,000 miles)
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.
