in 3-D!

Thanks to the data from the Express High Resolution Stereo Camera (HRSC), the Red Planet is about to come into 3D focus as never before.

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.

“Understanding the topography of is essential to understanding its geology,” says Prof. Gerhard Neukum, Freie Universität (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. 

Constructing a 3-D Digital Terrain Model requires a spacecraft to look at the same surface feature twice, each time from a different angle. Most attempts to do this in the past have required the spacecraft to target the same feature from two different orbital passes. The High Resolution Stereo Camera (HRSC) on Express is the only experiment that can do it in one pass. To achieve its complementary views, HRSC has nine individual scan lines that point fore, aft and straight down. It therefore sees a feature coming, sees it directly underneath and watches it recede into the distance, providing all the different angles needed.

NASA’s Global Surveyor carried a laser altimeter instrument (MOLA) that provided spot heights across the surface of Mars, but these were often separated by many kilometres. HRSC provides altitude data for every data point the camera sees. It is the first time that high-resolution images have been accompanied by high-resolution topography.

The Express-HRSC DTMs are available to the science community at large through the archives at the Planetary Science Archive (http://www.rssd.esa.int/PSA) at ESA and the Planetary Data System (http://pds-geosciences.wustl.edu/missions/mars_express/hrsc.htm) at NASA.

Posted by Casey Kazan.

Source links:

http://www.esa.int/SPECIALS/Mars_Express/SEM8Q2PR4CF_0.html