Image of the Day: Curiosity’s Science-Lab Laser Zaps 1st Mars’ Target




NASA's Mars rover Curiosity successfully tested its laser on Sunday, blasting a fist-size Martian rock and analyzing its makeup. The rover's Chemistry and Camera instrument, dubbed the ChemCam, zapped the rock with 30 pulses during a 10-second span, according to the space agency. With each pulse carrying more than a million watts of power in a five one-billionth-of-a-second burst, the laser turned the rock, which scientists named Coronation, into an ionized, glowing plasma.

At that point, the ChemCam, which sits on the rover's mast, caught the light from the plasma with a telescope and analyzed the specimen with three spectrometers to discover what the rocks are made of, NASA said. The ChemCam recorded spectrum after each of the 30 laser pulses.

"We got a great spectrum of Coronation — lots of signal," said ChemCam principal investigator Roger Wiens of the Los Alamos National Laboratory, in a statement. "Our team is both thrilled and working hard, looking at the results. After eight years building the instrument, it's payoff time."

This was the Curiosity's roving Science Lab first big task in its historic sdearch for life near the base of Mount Sharp. Within the week, the rover will begin by heading for one of four scars that its own landing gear scoured into the soil when the Sky Crane that lowered Curiosity into Gale Crater on 5 August hovered above the rover using four retro rockets. The rockets propelled Curiosity to a crash landing about half a kilometre away. Before the jetpack flew off, the rockets blew the rusty Martian dust off the planet's surface, exposing bedrock beneath.



The Mars Science Laboratory Curiosity rover ChemCam team received the first photos from the instrument’s remote micro imager. The successful capture of ChemCam’s first 10 photos sets the stage for the first test bursts of the instrument’s rock-zapping laser.

When ChemCam fires its extremely powerful laser pulse, it briefly focuses the energy of a million light bulbs onto an area the size of a pinhead. The laser blast vaporizes a small amount of its target up to seven meters (23 feet) away. The ChemCam system is one of 10 instruments mounted on the Curiosity rover—a six-wheeled mobile laboratory that will roam more than 12 miles of the planet’s surface during the course of one Martian year (98 Earth weeks).

The resultant flash of glowing plasma is viewed by the system’s 4.3-inch aperture telescope, which sends the light down an optical fiber to a spectrometer located in the body of the rover. There the colors of the light from the flash are recorded, enabling scientists to determine the elemental composition of the vaporized material. ChemCam also has a high-resolution camera that provides close-up images of an analyzed location. It can image a human hair from seven feet away. The ChemCam system is designed to capture as many as 14,000 observations throughout the mission.

“The successful delivery of these photos means we can begin efforts in earnest for the first images of Mars rocks by the ChemCam instrument and the first use of the instrument’s laser,” said Los Alamos National Laboratory planetary scientist Roger Wiens, Principal Investigator of the ChemCam Team. 

Scientists and engineers from NASA’s Curiosity rover mission selected ChemCam’s first target, a three-inch rock designated N-165 located near the rover.

“Rock N-165 looks like your typical Mars rock, about three inches (seven centimeters) wide and it's about 10 feet away,” Wiens said. “We are going to hit it with 14 milliJoules of energy 30 times in 10 seconds. It is not only going to be an excellent test of our system, but it should be pretty cool too.”

"That will be our first science target," said John Grotzinger,  project manager of NASA's Mars Science Laboratory mission. The rover will head towards a scar the team is calling Goulburn –named for ancient billlion-year-old rock formations in Northern Canada.

The Science Lab's ChemCam zaps rocks with a pinpoint of laser light to produce a small, hot puff of plasma and uses a telescopic camera and on-board spectrometers to get a quick read on its composition. Once it warms up, the laser tool will probably be one of the most-used instruments on the rover, set to make up to 14,000 individual analyses.

But the Curiosity team first needed to make sure the instrument knows what it's looking for. The rover carries a palette of nine circles of material akin to what scientists expect to find on Mars – for instance, glass samples represent igneous rock formed in volcanoes, while ceramics represent sedimentary rock. The camera has taken images of each of the specific calibration target. 

The ChemCam laser will shoots its target 30 times in 10 seconds. Wiens hopes that the barrage of laser shots will get underneath the Martian dust, to help figure out how deep it goes and what materials lie beneath. ChemCam will zap the bedrock exposed in Goulburn, which looks like it might be a conglomeration of different rocks cemented together. The rocks at Goulburn appear to be loosely bound, Grotzinger said, so the team decided the scar wouldn't be a good place to try out another sampling instrument, the arm-mounted drill, for the first time.

The real bonanza is a place where three types of rock appear to come together, named "Glenelg," to the east of Curiosity's landing site. "Glenelg simply looks distinctive and interesting," Grotzinger said. "Mostly it just looks cool." But it could take three to four weeks of straight driving to make it to Glenelg. And if the team encounters some nice loose soil, they'll probably stop and dig it up to give the chemistry suite its first taste of Martian ground.

"We always keep in mind that our real goal for having chosen this landing site is Mount Sharp itself," Grotzinger said. Twice as tall as the sequence of colorful bands exposed in Arizona's Grand Canyon, the stack of layers in Mount Sharp results from changing environments in which layers are deposited, younger on top of older, eon after eon, and then partially eroded away.

"Mount Sharp is the only place we can currently access on Mars where we can investigate this transition in one stratigraphic sequence," said Grotzinger. "The hope of this mission is to find evidence of a habitable environment; the promise is to get the story of an important environmental breakpoint in the deep history of the planet. This transition likely occurred billions of years ago — maybe even predating the oldest well-preserved rocks on Earth."

Possible explanations for how erosion shaped the mountain after layers were deposited include swirling winds carving away the edges, and perhaps later wet episodes leaving channels down the sides and fresher sediments on the crater floor. Clues about those episodes present Curiosity with other potentially habitable environments to investigate.



The Daily Galaxy via NASA/JPL-Caltech/Univ. of Arizona


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