Endurance, Over the Precipice

Categories: Feature Stories Mars

This 180-degree view [false-color] from the navigation camera on the Mars Exploration Rover Opportunity is the first look inside "Endurance Crater." The view is a cylindrical projection constructed from four images. The crater is about 130 meters (about 430 feet) in diameter.

The rover failed to escape Eagle crater on its first try as it reached a 17 degree incline and very fine dust at the rim. After making no progress but downward trenching, the rover backed up and headed for a shallower escape.
Credit: NASA/JPL

Plans are for the rover first to circumnavigate the 1,350-foot perimeter of the crater, then mission planners will be faced with the tough decision about whether to go into Endurance. One potential hazard that choice might entail stems from the steep walls and fine soil.

Even when exiting the much smaller Eagle Crater (about 1/7th the size of Endurance), the rover eventually ground to a halt. The rover’s wheels are generally rated to between 15 and 20 degrees for climbing slopes, but particularly near a crater rim, the soil is thought to resemble talcum or powdered cement, rather than sand.

Scientists expect to release a spectacular color, high-resolution panorama of Endurance for their next news conference scheduled Thursday.

Mars Global Surveyor image of landing site, showing Endurance Crater. Click image for larger view.
Credit: Malin Space Systems/NASA/JPL

One characteristic that struck onlookers even from a distance was the layering along the rim and similarity of light colored outcrops thought to represent ancient Martian bedrock. Such stratigraphy reveals a layered history, where the newest sediments deposit on top and the older material is exposed below. By reading this layering like tree rings, scientists hope to read more chapters of their ongoing mystery: what happened to surface water on Mars?

Compared to the most detailed layer at Eagle crater (about 16 inches high), the much older and deeper layers at Endurance appear to be up to 8 feet tall in places. The more layers, the farther back in martian times the bedrock may reveal.

A key scientific objective for this part of Opportunity’s extended mission will be to seek geologic context for the outcrop in the "Eagle" crater by reaching other outcrops in the "Endurance" crater and perhaps elsewhere. Other science objectives are to continue atmospheric studies at both sites to encompass more of Mars’ seasonal cycle and to calibrate and validate data from Mars orbiters for additional types of rocks and soils examined on the ground.

Meanwhile on the opposite side of the planet, the Spirit rover logged another record-breaking day of driving. The last odometer reading turned nearly 100 yards, a goal-to-goal trek traversing the length of a football field.

"We’re going to continue exploring and try to understand the water story at Gusev," said JPL’s Dr. Mark Adler, deputy mission manager for Spirit. Spirit is in pursuit of geological evidence for an ancient lake thought to have once filled Gusev Crater. Reaching "Columbia Hills," which could hold geological clues to that water story, is one of several objectives for the extended mission.

New engineering objectives are to traverse more than a kilometer (0.62 mile) to demonstrate mobility technologies; to characterize solar-array performance over long durations of dust deposition at both landing sites; and to demonstrate long-term operation of two mobile science robots on a distant planet. During the past month or so, rover teams at JPL have switched from Mars-clock schedules to Earth-clock schedules designed to be less stressful and more sustainable over a longer period towards what is hoped will be another September mission extension.

MER flight planning chronicled in the diary of the principal investigator for the science packages, Dr. Steven Squyres: Parts 1 * 2 * 3 * 4 * 5 * 6 * 7 * 8 * 9 * 10 * 11 *12.

Related Web Pages

JPL Rovers
Spirit’s Sol images and slideshow
Opportunity image gallery and slideshow
Mars Berries Once Rich in Iron-Water
NASA’s RATs Go Roving on Mars

Water Signs
Microscopic Imager
Gusev Crater
Pancam– Surveying the Martian Scene
Mössbauer spectrometer
Alpha Proton X-ray Spectrometer