NASA's 12-year-old Opportunity rover recently faced a downhill battle on Mars.
As it climbed up the steepest slope ever tackled by a rover, Opportunity got stuck — failing to get within reach of a certain target. The rover's tilt hit 32 degrees.
Opportunity's mountaineering skills were supposed to help it get close enough to study a rock near the crest of Knudsen Ridge, a Martian landform that is part of a larger feature known as Marathon Valley.
However, a new image released by NASA revealed that Opportunity did not quite reach its target on March 10, despite the healthy number of wheel rotations that could compensate for any possible slippage.
The rover only managed to progress on the slope about 3.5 inches because the slippage was so great, NASA said on Thursday. The wheels would have been enough to carry Opportunity about 66 feet had there been no slippage.
The March 10 drive was the rover's third attempt to reach the rock. It was also the steepest slope ever targeted by any Martian rover; it surpassed the Opportunity's own previous record for approaching Burns Cliff nine months after its January 2004 landing.
In the end, the rover team decided to skip the target and move on.
Opportunity has since then backed down the hill. In a series of drives that occurred over the past three weeks, Opportunity moved about 200 feet southward to a different target on Marathon Valley.
NASA said data from the Mars Reconnaissance Orbiter suggest that the rock targets harbor clay minerals, which form in the presence of liquid water.
Opportunity landed on Mars weeks after its twin, the Spirit rover, did.
Their mission was to search for evidence that liquid water once flowed on Mars. Both rovers found plenty of signs, and although their task was designed for three months, they kept moving along.
Spirit was declared dead in 2011. Opportunity, on the other hand, is still chugging along on the Red Planet, according to the Jet Propulsion Laboratory (JPL).
The rover is also instructed not to use flash memory but to transmit data quickly upon collecting it.
John Callas of JPL said each the rover transmits data that is collected for that day.
"Flash memory is a convenience but not a necessity for the rover," said Callas.
Incidentally, the Marathon Valley is aptly named because this is where Opportunity's odometer passed 42.2 kilometers, or 26.2 miles, the same distance of a marathon on Earth.
