[meteorite-list] Curiosity Rover Team Examining New Drill Hiatus

[Ron Baalke]

http://www.jpl.nasa.gov/news/news.php?feature=6692

Curiosity Rover Team Examining New Drill Hiatus
Jet Propulsion Laboratory
December 5, 2016

NASA's Curiosity Mars rover is studying its surroundings and monitoring 
the environment, rather than driving or using its arm for science, while 
the rover team diagnoses an issue with a motor that moves the rover's 
drill.

Curiosity is at a site on lower Mount Sharp selected for what would be 
the mission's seventh sample-collection drilling of 2016. The rover team 
learned Dec. 1 that Curiosity did not complete the commands for drilling. 
The rover detected a fault in an early step in which the "drill feed" 
mechanism did not extend the drill to touch the rock target with the bit.

"We are in the process of defining a set of diagnostic tests to carefully 
assess the drill feed mechanism. We are using our test rover here on Earth 
to try out these tests before we run them on Mars," Curiosity Deputy Project 
Manager Steven Lee, at NASA's Jet Propulsion Laboratory in Pasadena, California, 
said Monday. "To be cautious, until we run the tests on Curiosity, we 
want to restrict any dynamic changes that could affect the diagnosis. 
That means not moving the arm and not driving, which could shake it."

Two among the set of possible causes being assessed are that a brake on 
the drill feed mechanism did not disengage fully or that an electronic 
encoder for the mechanism's motor did not function as expected. Lee said 
that workarounds may exist for both of those scenarios, but the first 
step is to identify why the motor did not operate properly last week.

The drill feed mechanism pushes the front of the drill outward from the 
turret of tools at the end of Curiosity's robotic arm. The drill collects 
powdered rock that is analyzed by laboratory instruments inside the rover. 
While arm movements and driving are on hold, the rover is using cameras 
and a spectrometer on its mast, and a suite of environmental monitoring 
capabilities.

At the rover's current location, it has driven 9.33 miles (15.01 kilometers) 
since landing inside Mars' Gale Crater in August 2012. That includes more 
than half a mile (more than 840 meters) since departing a cluster of scenic 
mesas and buttes -- called "Murray Buttes" -- in September 2016. Curiosity 
has climbed 541 feet (165 meters) in elevation since landing, including 
144 feet (44 meters) since departing Murray Buttes.

The rover is climbing to sequentially higher and younger layers of lower 
Mount Sharp to investigate how the region's ancient climate changed, billions 
of years ago. Clues about environmental conditions are recorded in the 
rock layers. During its first year on Mars, the mission succeeded at its 
main goal by finding that the region once offered environmental conditions 
favorable for microbial life, if Mars has ever hosted life. The conditions 
in long-lived ancient freshwater Martian lake environments included all 
of the key chemical elements needed for life as we know it, plus a chemical 
source of energy that is used by many microbes on Earth.

Curiosity's drill, as used at all 15 of the rock targets drilled so far, 
combines hammering action and rotating-bit action to penetrate the targets 
and collect sample material. The drilling attempt last week was planned 
as the mission's first using a non-percussion drilling method that relies 
only on the drill's rotary action. Short-circuiting in the percussion 
mechanism has occurred intermittently and unpredictably several times 
since first seen in February 2015.

"We still have percussion available, but we would like to be cautious 
and use it for targets where we really need it, and otherwise use rotary-only 
where that can give us a sample," said Curiosity Project Scientist Ashwin 
Vasavada at JPL.

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

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

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

2016-309