Messenger’s first look at Mercury’s previously unseen side
Jan 16th, 2008 by RedPepper
When Mariner 10 flew past Mercury three times in 1974 and 1975, the same hemisphere was in sunlight during each encounter. As a consequence, Mariner 10 was able to image less than half the planet. Planetary scientists have wondered for more than 30 years about what spacecraft images might reveal about the hemisphere of Mercury that Mariner 10 never viewed.
On January 14, 2008, the Messenger spacecraft observed about half of the hemisphere missed by Mariner 10.
This image was snapped by the Wide Angle Camera, part of the Mercury Dual Imaging System (MDIS) instrument, about 80 minutes after Messenger’s closest approach to Mercury (2:04 p.m. EST), when the spacecraft was at a distance of about 27,000 kilometers (about 17,000 miles).
The image shows features as small as 10 kilometers (6 miles) in size. This image was taken through a filter sensitive to light near the red end of the visible spectrum (750 nm), one of a sequence of images taken through each of MDIS’s 11 filters.
Source: Messenger
(Image: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington)