High-Res Camera Image Released Online
Mars is about to come into focus as
never before, thanks to the data from the Mars Express High
Resolution Stereo Camera (HRSC). A new high-resolution Digital
Terrain Model data set, released this week onto the Internet, will
allow researchers to obtain new information about the Red Planet...
in 3-D, no less.
Digital Terrain Models (DTMs) allow scientists to 'stand' on
planetary surfaces. Although ordinary images can give spectacular
bird's-eye views, they can only convey part of the picture. They
miss out on the topography, or the vertical elevation of the
surroundings.
That's where the Mars Express comes in. The HRSC was especially
designed to provide this information and, after years of
specialised data processing, the first comprehensive release of 3D
data of a large part of the martian surface is now ready.
"Understanding the topography of Mars is essential to
understanding its geology," says Prof. Gerhard Neukum, Freie
Universitat (FU) Berlin, Germany, Principal Investigator for the
HRSC.
The DTM can instantly tell researchers the slope of hillsides or
the height of cliffs, the altitude and slope of lava flows or
desert plains. "This data is essential for understanding how water
or lava flowed across Mars," says Neukum.
It also helps planetary scientists to better interpret other
data sets, for example the results of the Mars Advanced Radar for
Subsurface and Ionosphere Sounding (MARSIS). "Once we know where
the surface is, we can correctly interpret the radar echoes we get
from below it," says former ESA scientist Angelo Rossi, a member of
the HRSC team.
The Mars Express DTM is the most detailed topographic data set
ever released for Mars. Its release has been made possible by
processing individual image swaths taken by the HRSC as Mars
Express sweeps through its orbit. The individual swaths are then
put together into mosaics that cover large regions. The
high-resolution images used have a resolution of 10 m/pixel. The
DTM elevation data derived from these images is provided in pixels
of up to 50 m, with a height accuracy of 10 m.
The orbit of Mars Express determines the resolution of its
pictures. When it is closest to the surface, it can take the most
detailed pictures. "As the mission continues, we are gradually
filling in the gaps and collecting high-resolution data whenever
possible," says Neukum.
The team plans to add more data to the DTMs to extend the
surface coverage as Mars Express continues its mission until at
least 2009 and HRSC continues its unique scrutiny of the
planet.