Keeping a watchful
eye - The Orbiters
2001 Mars Odyssey
2001 Mars Odyssey has survived longer than any other spacecraft in
orbit around a planet other than Earth and is the record holder for lon-
gevity among operational planetary missions, after the Voyagers and
Cassini. Named ‘in tribute to the vision and spirit of space exploration
as embodied in the works of renowned science fiction author Arthur C.
Clarke’, and launched on 7th April 2001, it arrived at Mars on 24th Oc-
tober 2001.
The mission’s main goals have been to study and map the global
distribution of different chemical elements and minerals that make up
the Martian surface. The orbiter has also provided valuable information
on the features and structure of the Martian surface and the processes
which may have been active in creating these.
MARS ODYSSEY VIEWS MINERALS AT CURIOSITY’S HOME
This mosaic image of the 154 km (96 mile) diameter Gale
Crater, home to MSL Curiosity on Mars, was made using
data from the Thermal Emission Imaging System (THEMIS)
on NASA’s Mars Odyssey orbiter. The false colours repre-
sent different mineral compositions. For example, windblown
dust appears pale pink and olivine-rich basalt looks purple.
The bright pink on Gale’s floor appears due to a mix of
basaltic sand and windblown dust. The blue at the summit
of Gale’s central mound, Mount Sharp, probably comes from
local materials exposed there. Typical Martian surface soil
appears grayish-green. Mission scientists use such false-
colour images to identify places of potential geological inter-
est, one key factor in the choice of Gale Crater/Mount Sharp
as a landing site for MSL in 2012 Credit: NASA/JPL-Caltech/
Arizona State University
Odyssey has also sought to find evidence of present or past water
and ice. One way of doing this is to determine the abundance of hy-
drogen in the shallow subsurface, and the probe’s studies led mission
scientists to discover vast water ice deposits buried just below the sur-
face in the Martian Polar regions.
Finally, the orbiter has conducted important measurements of Mars’
radiation environment. This is invaluable in helping to determine the
likely health risks for human explorers.
Odyssey’s primary science mission ended in August 2004, since then
the orbiter has fulfilled a series of extended missions. It broke the record
for longest serving spacecraft at Mars on 15th December 2010, and
continues to study Martian geology and climate, as well as serving as a
communications relay for the rovers on the planet’s surface. The space-
craft is in good shape and could continue operating until 2025.
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