See Mars in 3-D

The towering 3-D features of Martian canyons and highlands are about to stand out like never before, thanks to data from a high-resolution camera on the Mars Express orbiter.

These data, collected by the camera on the European Space Agency's Mars Express, are allowing scientists to create so-called Digital Terrain Models (DTMs) to look around the Martian surface from different directions and angles, as opposed to the usual bird's-eye view from above provided by previous Mars orbiter cameras. The new data sets have now been released on the Internet, the European Space Agency announced this week.

?Understanding the topography of Mars is essential to understanding its geology,? said Gerhard Neukum, HRSC lead scientist at Freie Universit?t (FU) in Berlin, Germany.

Creating the data for such digital models requires spacecraft to study the same Martian feature at least twice, each time from a different angle. Most previous efforts to do this have involved spacecraft making two orbital passes over features.

The Mars Express High Resolution Stereo Camera (HRSC) only needs one overhead pass to capture images of a feature from three different angles ? on approach, directly underneath and receding into the distance. The camera also obtains altitude measurements for its high-resolution images.

All that data is processed by the German Space Agency (DLR) and FU Berlin for several years before digital models of the Martian surface can start to emerge. Now researchers are selecting the best data to "stitch them together" and develop digital models on a "global scale," Fred Jansen, Mars Express senior manager, told

The newly released DTMs allow researchers to instantly gauge the slope of hillsides or the height of cliffs, as well as the altitude and slope of lava flows or desert plains.

?This data is essential for understanding how water or lava flowed across Mars,? Neukum said.  

It also helps planetary scientists better interpret Martian data from other instruments and missions, such as the Mars Advanced Radar for Subsurface and Ionosphere Sounding.

?Once we know where the surface is, we can correctly interpret the radar echoes we get from below it,? said Angelo Rossi, HRSC scientist.

Lower orbits of Mars Express allow for more detailed pictures. The Mars Express mission will continue collecting such data until at least 2009.

Jeremy Hsu
Jeremy has written for publications such as Popular Science, Scientific American Mind and Reader's Digest Asia. He obtained his masters degree in science journalism from New York University, and completed his undergraduate education in the history and sociology of science at the University of Pennsylvania.