Rover Platform, Instruments,
In typical field work, rover operations follow a daily
cycle in which a remote science team reviews the pri-
or data, decides the next day’s navigation waypoints
and measurements, and then sends these commands
to the rover over a satellite link. This is similar to the
sporadic communications of a planetary mission.
The rover then executes its commands over the
course of the subsequent day. In the Atacama cam-
paign, typical command cycles for Zoë cover 5–10
kilometers per day. Figure 2 shows the entire traverse
path: red dots show locations for imaging and spec-
tral data collection, while white paddles indicate sites
of particular interest where more in-depth study is
Scientists determine the waypoints for the next
day using geologic and compositional maps produced from orbital remote sensing data. Here the
ASTER instrument proves particularly useful: its
images have a spatial resolution of 15 meters (visible)
and 30 meters (SWIR), making them capable of
resolving details such as isolated rock outcrops.
While the three visible and six SWIR bands are not
sufficient to conclusively identify mineralogical
composition, they do help discriminate the principal units of surface material and suggested representative sites to visit.
Figure 3 shows examples of the different data
products: a Landsat image with three visible bands
reveals terrain morphology and desirable outcrops,
and a multiband ASTER image provides a rough classification of mineralogical units.
The rover itself is capable of driving more than 10
kilometers per day on challenging desert terrain
(Wettergreen et al. 2008). On-board obstacle avoidance uses three-dimensional geometry from stereo
imagery to identify hazards above the ground plane
and plan local drive arcs that go around them (figure
4). Figure 5 shows the robot and the components
used by its science autonomy system. A pair of for-ward-facing navigation cameras provide hazard
avoidance capability through a local path planner.
The vertical drill structure delivers subsurface soil to
a microscopic imager and a Raman spectrometer
inside the rover. Analyzing the drill samples takes an
hour or more, so these are deployed judiciously at
specific locations. However, we found that autono-
Figure 4. Hazard Avoidance.