[现代操作系统]-Modern-Operating-Systems,-Tanenbaum,-3Rd-Edition,-International-Version-(Pearson,-2009,-0138134596)-552s_部分5.pdf

North
West
Landing sites: + operational spacecraft * spacecraft lost on landing South
A global topographic map of the Mars, obtained from data acquired by the Mars Orbiter Laser
Altimeter (MOLA) carried by the Mars Global Surveyor spacecraft. Thanks to this instrument, the global
topography of Mars is now known to a greater precision than that of the Earth. The major surface features of
Mars, referred to in this book, are labelled here: the volcanoes (Mons, Patera), the plains and impact basins
(Planitia), the valleys and canyons (Valles). In the absence of oceans, `zero elevation' on Mars (the equivalent
of `mean sea level' on our ) corresponds to the 's average elevation, or the mean radius of the
. (Courtesy MOLA Science Team.)
East