January 30, 2014
NASA Curiosity Team Looks For Safer Route To Mount Sharp
[ Watch the Video: Curiosity Looking For A Safer Route ]
Lawrence LeBlond for redOrbit.com - Your Universe Online
The thinking is that Curiosity may be able to avoid some rough terrain that could poke holes in the rover’s aluminum wheels. While the main objective for the team is to make progress reaching its next drilling site along Mount Sharp, mission controllers are also looking for ways to reduce wear and tear on the wheels.
Curiosity has driven a total of 3.04 miles since landing on the Red Planet in August 2012. So far this year, the rover has driven 865 feet. Punctures and rips in the wheels have been more noticeable after a turbulent fourth quarter journey in 2013. The team is now looking to take added precautions during drives, thoroughly checking the condition of the wheels often and evaluating safer routes that could avoid further wheel damage.
In the hunt for a safer route, the team has possibly found solace in a sand dune measuring about three feet high that spans a gap between two scarps. The team sees this as a potential gateway to a southwestward route over smoother terrain. As Curiosity approaches the area, called “Dingo Gap,” the team is assessing images to determine if the route is in fact passable.
"The decision hasn't been made yet, but it is prudent to go check," said Curiosity project manager Jim Erickson of NASA's Jet Propulsion Laboratory, Pasadena, Calif. "We'll take a peek over the dune into the valley immediately to the west to see whether the terrain looks as good as the analysis of orbital images implies."
The sand dune route is only one option for Curiosity. The team is also assessing other paths that can take the rover to its next candidate drilling site, called “KMS-9.” That destination is about 2600 feet away by straight line, but considerably farther when factoring in any of the potentially safer routes currently being assessed.
The High Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter has provided the team with orbital images of potential routes and the terrain of KMS-9. The characteristics seen in the images so far appeal to the mission operators.
"At KMS-9, we see three terrain types exposed and a relatively dust-free surface," said science team collaborator Katie Stack of the California Institute of Technology, Pasadena.
"This area is appealing because we can see terrain units unlike any that Curiosity has visited so far. One unit has striations all oriented in a similar direction. Another is smooth, without striations. We don't know yet what they are. The big draw is exploration and seeing new things," said Stack.
Part of the precautions being taken for the NASA Curiosity team is using a test rover on Earth at JPL. The team is currently testing to see how able the rover is at tolerating slight slippage on slopes while using the drill. So far, tests on slips of about two inches while the drill is in rock have not caused any damage to the rover.
"These tests are building confidence for operations we are likely to use when Curiosity is on the slopes of Mount Sharp," said JPL's Daniel Limonadi, systems engineering leader for surface sampling with the rover's arm.
The team is also testing possible driving techniques with the Earth-based test rover that could help reduce the rate of wheel punctures, such as driving backwards or using four-wheel drive instead of six-wheel drive. The team believes that some of the wheel damage may result from the force of the rear wheels pushing the middle and front wheels against sharp rocks. Previous thinking was that the weight of the rover may have been causing most of the wheel damage while traveling over rough terrain.
"An analogy is when you are rolling your wheeled luggage over a curb, you can feel the difference between trying to push it over the curb or pull it over the curb," said JPL's Richard Rainen, mechanical engineering team leader for Curiosity.
The team will continue to evaluate potential routes and driving techniques and will bring in weekend and evening help to plan a safer route for Curiosity. It could be a month or longer before a final decision on a safe driving route is made.