Journey (Not the Destination)

Journey (Not The Destination)

There are only a handful of features that rise above the vast plain of the Gusev landing site. The hills are not that big, nor are they that distinctive. Even the highest resolution images from the Mars Orbital Camera (MOC) don’t show every little bump and dip on the Martian surface. So it’s hard to tell whether the hills to the east of the Spirit lander are this tiny dark spot on a MOC image, or that one. To help find the exact coordinates in Gusev, new overhead views released Tuesday have mapped the Mars Exploration Rover Spirit’s approximate location in relation to nearby craters and hills.

Gusev crater, from Mars Orbital Camera on Mars Global Surveyor. Credit: NASA/JPL/MSSS

By combining images from both the camera on Mars Global Surveyor and the descent image motion estimation system camera (or DIMES) located on the bottom of the rover’s lander, scientists and engineers can tell how far away the hills are from the rover. In the large overhead shot, the hills and hill ranges are marked by yellow lines, and the rover is located where the yellow lines intersect. Black arrows locate the east hill complex, a potential rover destination.

In the panoramic distance stand the east hills, which are closest to the Mars Exploration Rover Spirit in comparison to other hill ranges seen on the martian horizon. The top of the east hills are approximately 2 to 3 kilometers (1 to 2 miles) away from the rover’s approximate location. Early guesses formulated before this exacting work was completed put the hills at about 50 to 100 meters (about 165 to 330 feet) high and between 1 and 2 kilometers (about half a mile to a mile) away.

Click for larger panoramic view.
Credit: NASA/JPL/ Cornell

The difference in distances may be significant since at full speed, the rover can clock a maximum of about 50 meters per sol. So even if the hills turn out to be only one more kilometer away to the east, it will take Spirit about 20 days to get to them if they indeed are closer to 2 to 3 kilometers away.

As seen from overhead, hills to the north and southwest, along with a southern mesa are probably beyond the range reachable in the first ninety days of rover driving. The arrows in the 360-degree panoramic view of the martian surface identify hills and craters on the martian horizon that scientists can easily find with orbiters Mars Global Surveyor and Mars Odyssey.

What makes the eastern hills an interesting target is that they may be much older than the rocks and soil in the vicinity of the landing site – perhaps billions of years older. If they are, they would tell a story about a completely different time in the history of Gusev Crater than the nearby rocks and soil.

Click for larger image.
Credit: NASA/JPL/ MSSS

The overview maps show the estimated location of the Mars Exploration Rover Spirit to an accuracy probably around the length of a few school buses. The usual resolution of the Mars Orbital Camera is about 10-30 meters on the surface, and this overhead satellite asset has logged over 100,000 surface images.

The location measurements combine several different sources–three taken during the rover’s descent by the Deep Space Network along with others taken on the ground by both the Deep Space Network and the orbiter Mars Odyssey. When initially choosing a landing site for the rover, engineers avoided hazardous terrain such as steep hills or deep craters. At the scale of several kilometers, Gusev may look flat, but surface texture presents risks all the way down to the size of a few sharp rocks which can snag the airbag.


Related Web Pages

Water Signs
Microscopic Imager
Gusev Crater
Pancam - Surveying the Martian Scene
Mössbauer spectrometer
Alpha Proton X-ray Spectrometer
Mars Rover: The Owner’s Manual
Interview with Nathalie Cabrol – Pasadena, Spirit Mission Sol 4