[meteorite-list] Curiosity Maneuver Prepares for Drilling

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Mon, 28 Jan 2013 17:00:35 -0800 (PST)
Message-ID: <201301290100.r0T10Zke025212_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.php?release=2013-036

Curiosity Maneuver Prepares for Drilling
Jet Propulsion Laboratory
January 28, 2013

Mars Science Laboratory Mission Status Report

PASADENA, Calif. - NASA's Mars rover Curiosity has placed its drill onto
a series of four locations on a Martian rock and pressed down on it with
the rover's arm, in preparation for using the drill in coming days.

The rover carried out this "pre-load" testing on Mars yesterday (Jan.
27). The tests enable engineers to check whether the amount of force
applied to the hardware matches predictions for what would result from
the commanded motions.

The next step is an overnight pre-load test, to gain assurance that the
large temperature change from day to night at the rover's location does
not add excessively to stress on the arm while it is pressing on the
drill. At Curiosity's work site in Gale Crater, air temperature plunges
from about 32 degrees Fahrenheit (zero degrees Celsius) in the afternoon
to minus 85 degrees Fahrenheit (minus 65 degrees Celsius) overnight.
Over this temperature swing, this large rover's arm, chassis and
mobility system grow and shrink by about a tenth of an inch (about 2.4
millimeters), a little more than the thickness of a U.S. quarter-dollar
coin.

The rover team at NASA's Jet Propulsion Laboratory, Pasadena, Calif.,
sent the rover commands yesterday to begin the overnight pre-load test
today (Monday).

"We don't plan on leaving the drill in a rock overnight once we start
drilling, but in case that happens, it is important to know what to
expect in terms of stress on the hardware," said JPL's Daniel Limonadi,
the lead systems engineer for Curiosity's surface sampling and science
system. "This test is done at lower pre-load values than we plan to use
during drilling, to let us learn about the temperature effects without
putting the hardware at risk."

Remaining preparatory steps will take at least the rest of this week.
Some of these steps are hardware checks. Others will evaluate
characteristics of the rock material at the selected drilling site on a
patch of flat, veined rock called "John Klein."

Limonadi said, "We are proceeding with caution in the approach to
Curiosity's first drilling. This is challenging. It will be the first
time any robot has drilled into a rock to collect a sample on Mars."

An activity called the "drill-on-rock checkout" will use the hammering
action of Curiosity's drill briefly, without rotation of the drill bit,
for assurance that the back-and-forth percussion mechanism and
associated control system are properly tuned for hitting a rock.

A subsequent activity called "mini-drill" is designed to produce a small
ring of tailings -- powder resulting from drilling -- on the surface of
the rock while penetrating less than eight-tenths of an inch (2
centimeters). This activity will not go deep enough to push rock powder
into the drill's sample-gathering chamber. Limonadi said, "The purpose
is to see whether the tailings are behaving the way we expect. Do they
look like dry powder? That's what we want to confirm."

The rover team's activities this week are affected by the difference
between Mars time and Earth time. To compensate for this, the team
develops commands based on rover activities from two sols earlier. So,
for example, the mini-drill activity cannot occur sooner than two sols
after the drill-on-rock checkout.

Each Martian sol lasts about 40 minutes longer than a 24-hour Earth day.
By mid-February, the afternoon at Gale Crater, when Curiosity transmits
information about results from the sol, will again be falling early
enough in the California day for the rover team to plan each sol based
on the previous sol's results.

NASA's Mars Science Laboratory Project is using Curiosity to assess
whether areas inside Gale Crater ever offered a habitable environment
for microbes. JPL, a division of the California Institute of Technology
in Pasadena, manages the project for NASA's Science Mission Directorate
in Washington.

More information about Curiosity is online at
http://www.jpl.nasa.gov/msl , http://www.nasa.gov/msl and
http://mars.jpl.nasa.gov/msl/ . You can follow the mission on Facebook
at: http://www.facebook.com/marscuriosity and on Twitter at:
http://www.twitter.com/marscuriosity .

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

2013-036
Received on Mon 28 Jan 2013 08:00:35 PM PST