Mars-Bound NASA Rover Carries Coin for Camera Checkup

The camera at the end of the robotic arm on NASA's Mars rover Curiosity has its own calibration target, a smartphone-size plaque that looks like an eye chart supplemented with color chips and an attached penny.
When Curiosity lands on Mars in August, researchers will use this calibration target to test performance of the rover's Mars Hand Lens Imager, or MAHLI. MAHLI's close-up inspections of Martian rocks and soil will show details so tiny, the calibration target includes reference lines finer than a human hair. This camera is not limited to close-ups, though. It can focus on any target from about a finger's-width away to the horizon.
Curiosity, the rover of NASA's Mars Science Laboratory mission, also carries four other science cameras and a dozen black-and-white engineering cameras, plus other research instruments. The spacecraft, launched Nov. 26, 2011, will deliver Curiosity to a landing site inside Mars' Gale Crater in August to begin a two-year investigation of whether that area has ever offered an environment favorable for microbial life.
The "hand lens" in MAHLI's name refers to field geologists' practice of carrying a hand lens for close inspection of rocks they find. When shooting photos in the field, geologists use various calibration methods.
"When a geologist takes pictures of rock outcrops she is studying, she wants an object of known scale in the photographs," said MAHLI Principal Investigator Ken Edgett, of Malin Space Science Systems, San Diego. "If it is a whole cliff face, she'll ask a person to stand in the shot. If it is a view from a meter or so away, she might use a rock hammer. If it is a close-up, as the MAHLI can take, she might pull something small out of her pocket. Like a penny."
Edgett bought the special penny that's aboard Curiosity with funds from his own pocket. It is a 1909 "VDB" cent, from the first year Lincoln pennies were minted, the centennial of Abraham Lincoln's birth, with the VDB initials of the coin's designer -- Victor David Brenner -- on the reverse.
"The penny is on the MAHLI calibration target as a tip of the hat to geologists' informal practice of placing a coin or other object of known scale in their photographs. A more formal practice is to use an object with scale marked in millimeters, centimeters or meters," Edgett said. "Of course, this penny can't be moved around and placed in MAHLI images; it stays affixed to the rover."
The middle of the target offers a marked scale of black bars in a range of labeled sizes. While the scale will not appear in photos MAHLI takes of Martian rocks, knowing the distance from the camera to a rock target will allow scientists to correlate calibration images to each investigation image.
Another part of MAHLI's calibration target displays six patches of pigmented silicone as aids for interpreting color and brightness in images. Five of them -- red, green, blue, 40-percent gray and 60-percent gray -- are spares from targets on NASA Mars rovers Spirit and Opportunity. The sixth, with a fluorescent pigment that glows red when exposed to ultraviolet light, allows checking of an ultraviolet light source on MAHLI. The fluorescent material was donated to the MAHLI team by Spectra Systems, Inc., Providence, R.I.
A stair-stepped area at the bottom of the target, plus the penny, help with three-dimensional calibration using known surface shapes.
Curiosity also carries calibration materials for other science instruments on the rover. "The importance of calibration is to allow data acquired on Mars to be compared reliably to data acquired on Earth," said Mars Science Laboratory Project Scientist John Grotzinger, of the California Institute of Technology, Pasadena.
The MAHLI calibration target, with its penny and a miniscule cartoon of a character named "Joe the Martian," serves an additional function: public engagement.
"Everyone in the United States can recognize the penny and immediately know how big it is, and can compare that with the rover hardware and Mars materials in the same image," Edgett said. "The public can watch for changes in the penny over the long term on Mars. Will it change color? Will it corrode? Will it get pitted by windblown sand?"
The Joe the Martian character appeared regularly in a children's science periodical, "Red Planet Connection," when Edgett directed the Mars outreach program at Arizona State University, Tempe, in the 1990s. Joe was created earlier, as part of Edgett's schoolwork when he was 9 years old and NASA's Mars Viking missions, launched in 1975, were inspiring him to dream of becoming a Mars researcher.
Edgett said, "The Joe the Martian on Curiosity really is a 'thank you' from the MAHLI team to the folks who have provided us with the opportunity to study Mars, the U.S. taxpayers. He is also there to encourage children around the world to set goals that will help them achieve their dreams in whatever interests they pursue."
The Mars Science Laboratory is managed by NASA's Jet Propulsion Laboratory, a division of the Caltech. For more information, visit http://www.nasa.gov/msl .

Spirit Lander – 1st Color Image from Mars Orbit

1st Color image of Spirit lander and Bonneville Crater from Mars orbit
Near the lower left corner of this view is the three-petal lander platform that NASA's Mars Exploration Rover Spirit drove off in January 2004. Credit: NASA/JPL-Caltech/Univ. of Arizona
See more images of Spirit’s lander from orbit and her Traverse Map below
What did Spirit see from the lander ? - look below

The Lander platform for NASA’s Spirit rover has been photographed in stunning high resolution color for the first time from Mars orbit – just over 8 years after the now legendary robot survived the scorching atmospheric heat of the 6 minute plunge through the Martian atmosphere and bounced to a stop inside Gusev Crater on January 3, 2004.
Spirit’s three petaled landing pad was finally imaged in color by NASA’s powerful Mars Reconnaissance Orbiter (MRO) spacecraft just days ago on January 29, 2012 at 3:04 p.m. local Mars time.
The MRO spacecraft was soaring overhead and captured the image of Spirit’s lander with the high resolution HiRISE camera from a distance of some 262 kilometers, (162 miles).
“HiRISE has never before imaged the actual lander for the Spirit rover in color, [located] on the west side of Bonneville Crater,” writes Alfred McEwen, HiRISE Principal Investigator at the University of Arizona.

1st Color image of Spirit Lander and Bonneville Crater from Mars orbit
Spirit landing pad at lower left; Bonneville Crater rim at top right.
Credit: NASA/JPL/UA/HiRISE

While protectively cocooned inside the airbag cushioned lander, Spirit bounced about two dozen times before rolling to rest on the Martian plains about ¼ mile away from Bonneville Crater. Then her landing petals unfurled, the airbags were partially retracted and Spirit eventually drove off the landing pad.
“The lander is still bright, but with a reddish color, probably due to a [Martian] dust cover.”

Spirit rover images her Lander Platform after Egress
- Now imaged for the 1st time from Mars orbit by NASA’s MRO spacecraft. Lander had 3-petals and airbags. Credit: NASA/JPL-Caltech/Cornell

Spirit initially drove to Bonneville Crater and circumnavigated part way around the rim before speeding off towards the Columbia Hills, about 2 miles to the East. She eventually scaled the summit of Husband Hill and drove down the opposite side to the Home Plate” volcanic feature where she rests today – see travse map below.
“A bright spot from a remnant of the heat shield is still visible on the north rim of Bonneville Crater. The backshell and parachute are still bright, but were not captured in the narrow color swath.”
“The rover itself can still be seen near “Home Plate” in the Columbia Hills, but there is no obvious sign of rover tracks–erased by the wind,” McEwen notes.
Here is a photo taken by Spirit looking back to the lander – now imaged in color from orbit for the first time – for a comparative view, before she drove off forever.
Spirit endured for more than six years of bonus time exploration beyond her planned 90 day mission. And Opportunity is still roving Mars today !

Spirit Rover traverse map from Gusev Crater landing site near Bonneville Crater to Columbia Hills to Home Plate: 2004 to 2011. Credit: NASA/JPL/UA/HiRISE

Curiosity – NASA’s newest, biggest ever and maybe last Mars rover – is speeding through interplanetary space for an August 2012 landing inside Gale Crater.

Surface of Mars an Unlikely Place for Life After 600-Million-Year Drought, Say Scientists

Mars may have been arid for more than 600 million years, making it too hostile for any life to survive on the planet's surface, according to researchers who have been carrying out the painstaking task of analysing individual particles of Martian soil. Dr Tom Pike, from Imperial College London, will discuss the team's analysis at a European Space Agency (ESA) meeting on 7 February 2012.
The researchers have spent three years analysing data on Martian soil that was collected during the 2008 NASA Phoenix mission to Mars. Phoenix touched down in the northern arctic region of the planet to search for signs that it was habitable and to analyse ice and soil on the surface.
The results of the soil analysis at the Phoenix site suggest the surface of Mars has been arid for hundreds of millions of years, despite the presence of ice and the fact that previous research has shown that Mars may have had a warmer and wetter period in its earlier history more than three billion years ago. The team also estimated that the soil on Mars had been exposed to liquid water for at most 5,000 years since its formation billions of years ago. They also found that Martian and Moon soil is being formed under the same extremely dry conditions.
Satellite images and previous studies have proven that the soil on Mars is uniform across the planet, which suggests that the results from the team's analysis could be applied to all of Mars. This implies that liquid water has been on the surface of Mars for far too short a time for life to maintain a foothold on the surface.
Dr Pike, from the Department of Electrical and Electronic Engineering at Imperial, who is lead author on the study published in the journal Geophysical Research Letters, explains:
"We found that even though there is an abundance of ice, Mars has been experiencing a super-drought that may well have lasted hundreds of millions of years. We think the Mars we know today contrasts sharply with its earlier history, which had warmer and wetter periods and which may have been more suited to life. Future NASA and ESA missions that are planned for Mars will have to dig deeper to search for evidence of life, which may still be taking refuge underground."
During the Phoenix mission, Dr Pike and his research group formed one of 24 teams based at mission control in the University of Arizona in the USA, operating part of the spacecraft's onboard laboratories. They analysed soil samples dug up by a robot arm, using an optical microscope to produce images of larger sand-sized particles, and an atomic-force microscope to produce 3D images of the surface of particles as small as 100 microns across. Since the end of the mission, the team has been cataloguing individual particle sizes to understand more about the history of the Martian soil.
In the study, the researchers looked for the microscopic clay particles that are formed when rock is broken down by water. Such particles are an important marker of contact between liquid water and the soil, forming a distinct population in the soil. The team found no such marker. They calculated that even if the few particles they saw in this size range were in fact clay, they made up less than 0.1 percent of the total proportion of the soil in the samples. On Earth, clays can make up to 50 percent or more of the soil content, so such a small proportion in the Martian samples suggests that the soil has had a very arid history.
They estimated that the soil they were analysing had only been exposed to liquid water for a maximum of 5,000 years by comparing their data with the slowest rate that clays could form on Earth.
The team found further evidence to support the idea that Martian soil has been largely dry throughout its history by comparing soil data from Mars, Earth and the Moon. The researchers deduced that the soil was being formed in a similar way on Mars and the Moon because they were able to match the distribution of soil particle sizes. On Mars, the team inferred that physical weathering by the wind as well as meteorites breaks down the soil into smaller particles. On the Moon, meteorite impacts break down rocks into soil, as there is no liquid water or atmosphere to wear down the particles.
This research has received support from the UK Science and Technology Facilities Council; the Danish Research Agency; the Wolfermann-Nägeli Foundation, Switzerland; the Space Center at EPFL, Switzerland; the Swiss National Science Foundation; and the National Aeronautics and Space Administration.
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