Author's Archive: David O'Brien

David O'Brien
David O'Brien
David O’Brien, a Participating Scientist on the Dawn mission, is a Senior Scientist at the Planetary Science Institute. His research interests include planet formation and the evolution of the early Solar System, collisional and dynamical evolution of asteroids and small bodies, thermal modeling of geophysical phenomena, and icy satellite geophysics.


23 May

Vesta 360

by David O'Brien

The Dawn mission is currently en route to dwarf planet Ceres, its second destination. It spent a productive fourteen months orbiting its first destination, giant asteroid Vesta, in 2011-12, gathering splendid sets of data. The spacecraft may have moved on, but the science team continues to explore that data, enriching our understanding of Vesta’s formation and history.

Getting the “Big Picture”

Vesta: Clementine color ratios

Clementine color ratios

Vesta is a large protoplanet with remarkably variable topography—mountains, troughs, boulders, craters, cliffs, and more. The wealth of high-resolution imaging data from the Dawn mission has given us an amazing view of its surface. However, looking through individual frames or image mosaics can make it difficult to see its surface features in a global context and get the “big picture” of Vesta. On the other hand, the images taken early on as the mission approached the protoplanet show the whole of Vesta, but with low surface resolution. To better visualize Vesta at high resolution, I used the open-source program POV-Ray[1], combining images and topography data to create striking 3-D graphics.

The program let me take a shape model of Vesta, created from Dawn’s framing camera data by Bob Gaskell at the Planetary Science Institute, and wrap an image around it. For the image, I used a global mosaic[2] developed by our framing camera team partners at the German Aerospace Center (DLR) from high altitude mapping orbit clear-filter images. This mosaic has a resolution of 60 meters (about 200 feet) per pixel. I then used POV-Ray to make ‘snapshots’ of this model of Vesta as it rotated, varying the latitude from +45 to -45 degrees. Those individual frames were combined into the movie shown below.

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  1. [1] Persistence of Vision Raytracer
  2. [2] The global mosaics used here can be downloaded from this page at the Dawn Public Data website, although they are very large files. For labeled maps of smaller regions of the surface, see the Vesta Atlas.