[meteorite-list] Camera Duo on Mars Rover Mast Will Shoot Color Views (MSL)

[Ron Baalke]

http://www.jpl.nasa.gov/news/news.cfm?release=2011-166  

Camera Duo on Mars Rover Mast Will Shoot Color Views
Jet Propulsion Laboratory
May 31, 2011

Two digital color cameras riding high on the mast of NASA's next Mars
rover will complement each other in showing the surface of Mars in
exquisite detail.

They are the left and right eyes of the Mast Camera, or Mastcam,
instrument on the Curiosity rover of NASA's Mars Science Laboratory
mission, launching in late 2011.

The right-eye Mastcam looks through a telephoto lens, revealing details
near or far with about three-fold better resolution than any previous
landscape-viewing camera on the surface of Mars. The left-eye Mastcam
provides broader context through a medium-angle lens. Each can acquire
thousands of full-color images and store them in an eight-gigabyte flash
memory. Both cameras are also capable of recording high-definition video
at about eight frames per second. Combining information from the two
eyes can yield 3-D views of the telephoto part of the scene.

Motivation to put telephoto capability in Curiosity's main science
imaging instrument grew from experience with NASA's Mars Exploration
Rover Opportunity and its studies of an arena-size crater in 2004. The
science camera on that rover's mast, which can see details comparably to
what a human eye can see at the same distance, showed intriguing
patterns in the layers of Burns Cliff inside Endurance Crater.

"We tried to get over and study it, but the rover could not negotiate
the steep slope," recalled Mastcam Principal Investigator Michael Malin,
of Malin Space Science Systems, San Diego. "We all desperately coveted a
telephoto lens." NASA selected his Mastcam proposal later that year for
the Mars Science Laboratory rover.

The telephoto Mastcam, called "Mastcam 100" for its 100-millimeter
focal-length lens, provides enough resolution to distinguish a
basketball from a football at a distance of seven football fields, or to
read "ONE CENT" on a penny on the ground beside the rover. Its images
cover an area about six degrees wide by five degrees tall.

Its left-eye partner, called "Mastcam 34" for its 34-millimeter lens,
catches a scene three times wider -- about 18 degrees wide and 15
degrees tall -- with each exposure.

Researchers will use the Mastcams and nine other science instruments on
Curiosity to study past and present environments in a carefully chosen
area of Mars. They will assess whether conditions have been favorable
for life and favorable for preserving evidence about whether life has
existed there. Mastcam imaging of the shapes and colors of landscapes,
rocks and soils will provide clues about the history of environmental
processes that have formed them and modified them over time. Images and
videos of the sky will document contemporary processes, such as movement
of clouds and dust.

Previous color cameras on Mars have taken a sequence of exposures
through different color filters to be combined on Earth into color
views. The Mastcams record color the same way consumer digital cameras
do: They have a grid of tiny red, green and blue squares (a "Bayer
pattern" filter) fitted over the electronic light detector (the
charge-coupled device, or CCD). This allows the Mastcams to get the
three color components over the entire scene in a single exposure.

Mastcam's color-calibration target on the rover deck includes magnets to
keep the highly magnetic Martian dust from accumulating on portions of
color chips and white-gray-balance reference chips. Natural lighting on
Mars tends to be redder than on Earth due to dust in Mars' atmosphere.
"True color" images can be produced that incorporate that lighting
effect -- comparable to the greenish look of color-film images taken
under fluorescent lights on Earth without a white-balancing adjustment.
A white-balance calculation can yield a more natural look by adjusting
for the tint of the lighting, as the human eye tends to do and digital
cameras can do. The Mastcams are capable of producing both true-color
and white-balanced images.

Besides the affixed red-green-blue filter grid, the Mastcams have wheels
of other filters that can be rotated into place between the lens and the
CCD. These include science spectral filters for examining the ground or
sky in narrow bands of visible-light or near-infrared wavelengths. One
filter on each camera allows it to look directly at the sun to measure
the amount of dust in the atmosphere, a key part of Mars' weather.

"Something we're likely to do frequently is to look at rocks and
features with the Mastcam 34 red-green-blue filter, and if we see
something of interest, follow that up with the Mastcam 34 and Mastcam
100 science spectral filters," Malin said. "We can use the
red-green-blue data for quick reconnaissance and the science filters for
target selection."

When Curiosity drives to a new location, Mastcam 34 can record a
full-color, full-circle panorama about 60 degrees tall by taking 150
images in about 25 minutes. Using Mastcam 100, the team will be able to
broaden the swath of terrain evaluated on either side of the path
Curiosity drives, compared to what has been possible with earlier Mars
rovers. That will help with selection of the most interesting targets to
approach for analysis by Curiosity's other instruments and will provide
additional geological context for interpreting data about the chosen
targets.

The Mastcams will provide still images and video to study motions of the
rover -- both for science, such as seeing how soils interact with
wheels, and for engineering, such as aiding in use of the robotic arm.
In other videos, the team may use cinematic techniques such as panning
across a scene and using the rover's movement for "dolly" shots.

Each of the two-megapixel Mastcams can take and store thousands of
images, though the amount received on Earth each day will depend on how
the science team chooses priorities for the day's available
data-transmission volume. Malin anticipates frequent use of Mastcam
"thumbnail" frames -- compressed roughly 150-by-150-pixel versions of
each image -- as an index of the full-scale images held in the onboard
memory.

Malin Space Science Systems built the Mastcam instrument and will
operate it. The company's founder, Michael Malin, participated in NASA's
Viking missions to Mars in the 1970s, provided the Mars Orbiter Camera
for NASA's Mars Global Surveyor mission, and is the principal
investigator for both the Context Camera and the Mars Color Imager on
NASA's Mars Reconnaissance Orbiter.

The science team for Mastcam and two other instruments the same company
provided for Curiosity includes the lead scientist for the mast-mounted
science cameras on Mars rovers Spirit and Opportunity (James Bell of
Arizona State University); the lead scientist for the mast camera on
NASA's Phoenix Mars Lander (Mark Lemmon of Texas A&M University); James
Cameron, director of such popular movies as "Titanic" and "Avatar"; and
17 others with expertise in geology, soils, frost, atmosphere, imaging
and other topics.

Mastcam 100 and Mastcam 34 were installed onto Curiosity in 2010. Until
March 2011, a possibility remained open that they might be replaced with
a different design: two identical zoom cameras. A zoom camera has
adjustable focal length, to change from wider-angle to telephoto or
vice-versa. That design had been Malin's original proposal. NASA changed
the plan to two different fixed-focal-length cameras in 2007 as a
cost-cutting measure that preserves the capability for meeting the
science goals of the mission and the instrument. The agency funded a
renewed possibility for using the zoom-camera design in 2010, but the
zoom development presented challenges that could not be fully overcome
with enough time for required testing on the rover.

Mastcam 34 took images for a mosaic showing Curiosity's upper deck
during tests in March 2011 inside a chamber simulating Mars surface
temperature and air pressure. Testing of the rover at NASA's Jet
Propulsion Laboratory, Pasadena, Calif., will wrap up in time for
shipping the rover to NASA Kennedy Space Center in June. Testing and
other launch preparations will continue there. The launch period for the
Mars Science Laboratory is Nov. 25 to Dec. 18, 2011, with landing on
Mars in August 2012.

The Mars Science Laboratory is managed by JPL, a division of the
California Institute of Techology in Pasadena. For more information,
visit http://www.nasa.gov/msl . You can follow the mission on Facebook
at http://www.facebook.com/MarsCuriosity and on Twitter @marscuriosity .
A full listing of JPL social media accounts is at:
http://www.jpl.nasa.gov/social .

Guy Webster 818-687-7708
Jet Propulsion Laboratory, Pasadena, Calif.
Guy.webster at jpl.nasa.gov

2010-166