[meteorite-list] NASA's Curiosity Rover Adjusts Route Up Martian Mountain

[Ron Baalke]

http://www.jpl.nasa.gov/news/news.php?feature=4596

NASA's Curiosity Rover Adjusts Route Up Martian Mountain
Jet Propulsion Laboratory
May 22, 2015

Fast Facts:

* Alternative science site reached by climbing.

* Excessive slip prompted change in plans.

NASA's Curiosity Mars rover climbed a hill Thursday to approach an alternative 
site for investigating a geological boundary, after a comparable site 
proved hard to reach.

The drive of about 72 feet (22 meters) up slopes as steep as 21 degrees 
brought Curiosity close to a target area where two distinctive types of 
bedrock meet. The rover science team wants to examine an outcrop that 
contains the contact between the pale rock unit the mission analyzed lower 
on Mount Sharp and a darker, bedded rock unit that the mission has not 
yet examined up close.

Two weeks ago, Curiosity was headed for a comparable geological contact 
farther south. Foiled by slippery slopes on the way there, the team rerouted 
the vehicle and chose a westward path.The mission's strategic planning 
keeps multiple route options open to deal with such situations.

"Mars can be very deceptive," said Chris Roumeliotis, Curiosity's lead 
rover driver at NASA's Jet Propulsion Laboratory, Pasadena, California. 
"We knew that polygonal sand ripples have caused Curiosity a lot of drive 
slip in the past, but there appeared to be terrain with rockier, more 
consolidated characteristics directly adjacent to these ripples. So we 
drove around the sand ripples onto what we expected to be firmer terrain 
that would give Curiosity better traction. Unfortunately, this terrain 
turned out to be unconsolidated material too, which definitely surprised 
us and Curiosity."

In three out of four drives between May 7 and May 13, Curiosity experienced 
wheel slippage in excess of the limit set for the drive, and it stopped 
mid-drive for safety. The rover's onboard software determines the amount 
of slippage occurring by comparing the wheel-rotation tally to actual 
drive distance calculated from analysis of images taken during the drive.

The rover was heading generally southward from near the base of a feature 
called "Jocko Butte" toward a geological contact in the eastern part of 
the "Logan Pass" area.

Routes to this contact site would have required driving across steeper 
slopes than Curiosity has yet experienced on Mars, and the rover had already 
experienced some sideways slipping on one slope in this area.

"We decided to go back to Jocko Butte, and, in parallel, work with the 
scientists to identify alternate routes," Roumeliotis said.

The team spent a few days analyzing images from the rover and from NASA's 
Mars Reconnaissance Orbiter to choose the best route for short-term and 
long-term objectives.

"One factor the science team considers is how much time to spend reaching 
a particular target, when there are many others ahead," said Curiosity 
Project Scientist Ashwin Vasavada of JPL. "We used observations from NASA's 
Mars Reconnaissance Orbiter to identify an alternative site for investigating 
the geological contact in the Logan Pass area. It's a little mind-blowing 
to drive up a hill to a site we saw only in satellite images and then 
find it in front of us."

Curiosity has been exploring on Mars since 2012. It reached the base of 
Mount Sharp last year after fruitfully investigating outcrops closer to 
its landing site and then trekking to the mountain. The main mission objective 
now is to examine successively higher layers of Mount Sharp.

JPL, a division of the California Institute of Technology in Pasadena, 
built the rover and manages the project for NASA's Science Mission Directorate 
in Washington. For more information about Curiosity, visit:

http://www.nasa.gov/msl

http://mars.jpl.nasa.gov/msl

You can follow the mission on Facebook and Twitter at:

http://www.facebook.com/marscuriosity

http://www.twitter.com/marscuriosity


Media Contact

Guy Webster
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-6278
guy.webster at jpl.nasa.gov 

Dwayne Brown
NASA Headquarters, Washington
202-358-1726
dwayne.c.brown at nasa.gov 

2015-176