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Welcome to the MOLA Science investigation web page. MOLA is the Mars Orbiter Laser Altimeter, an instrument currently in orbit around Mars on the Mars Global Surveyor (MGS) spacecraft. The instrument transmits infrared laser pulses towards Mars at a rate of 10 Hz and measures the time of flight to determine the range of the MGS spacecraft to the Martian surface. Range measurements have been used to construct a precise topographic map of Mars that has many applications to studies in geophysics, geology and atmospheric circulation. MOLA also functions as a passive radiometer, and is currently measuring the radiance of the surface of Mars at 1064 nm.

Pole-to-pole topography of Mars

Above is a pole-to-pole view of Martian topography from the first MOLA global topographic model [Smith et al., Science, 1999]. The slice runs from the north pole (left) to the south pole (right) along the 0° longitude line. The figure highlights the pole-to-pole slope of 0.036°, such that the south pole has a higher elevation than the north pole by ~6 km. This global-scale slope was likely present for most of Mars' history and controlled the surface and subsurface transport of water indicated by images of outflow channels and valley networks. The regional high (in orange) in mid-southern hemisphere latitudes corresponds to the western edge of the topographic annulus that encircles the massive Hellas impact basin. In the figure warm colors correspond to high elevations and cold colors correspond to low elevations. Note the exceedingly flat northern hemisphere in blue. (Image credit: MOLA Science Team).
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