Introduction - Dune Worlds: How Windblown Sand Shapes Planetary Landscapes - page 9

Fig. 1.13 Erwin Rommel (with binoculars) in his Sd.Kfz 250/3 half-
track 'Greif' during the African campaigns. Half-tracks are a useful

compromise vehicle for difficult terrain, balancing traction and

manoeuvrability. Bundesarchiv—Wikimedia Commons

Fig. 1.14 Mike Seibert and Sharon Laubach, engineers on the Mars
Exploration Rover team at NASA's Jet Propulsion Laboratory,
Pasadena, check the exact position of a test rover in preparation for
the next test of a possible maneuver for Spirit to use on Mars. The test
setup at JPL simulates the situation where Spirit is embedded in a

patch of soft soil dubbed 'Troy', in Mars' Gusev Crater. The
preparation shown here on July 7, 2009, preceded an assessment of
straight-backward driving the next day, one of several possible
maneuvers assessed in the test sandbox. Image Credit NASA/JPL-
Caltech