Mars Rover Laser Hits Landmark

Since landing on Mars on 6 August, 2012, NASA’s Curiosity Mars rover has been exploring the planet’s surface and conducting experiments on soil and rocks. One of the mission’s key milestones was reached this week when the rover’s specialised on-board laser was fired for the 100,000th time as it continues to explore the planet’s history.

The laser, called ChemCam, is shot each time at a rock, creating a little ball of plasma or debris, Roger Wiens, the principal investigator of the ChemCam team, told eWEEK. “It abrades some material off of the rock’s surface, like a little ball of flame,” said Wiens, who is a planetary scientist at the Los Alamos National Laboratory, where the laser was developed.

Spectral signatures

After each shot, special instruments on the rover capture the spectral signatures of the laser firing, which are used to identify the elements that make up the soil on Mars, he said. Photographs are also taken to document the laser firing and to build a history of the experiments.

The ChemCam laser marks the first time that scientists on Earth have been able to do this kind of research on Mars, said Wiens. A previous Phoenix lander sent to Mars had a laser, but it was aimed into the planet’s atmosphere and couldn’t collect information about the rocks on Mars.

Other Mars lander missions used a robotic arm to scoop up soil for analysis, but that limited data collection to materials that could be grabbed by the arm, said Wiens. “So it took more effort than just point and shoot,” like researchers are able to do with the laser. “This mission provides much more data collection.”

Another important advantage to using the laser is that it is helping scientists get below the dusty surface of Mars to see what’s really there in the rocks, he said. “Remember, that Mars is a dusty place and these rocks tend to be covered by dust. So the passive tests [using previous arm-mounted scoops] show what’s on the surface, while the laser shots get below the surface” and reveal more information about the composition of the materials.

“It gives us a window that we wouldn’t have otherwise by using this laser,” said Wiens. “I think it’s fair to say that we are piecing the data together like pieces in a puzzle.”

One-year anniversary

So far, the Curiosity, which celebrated its one-year anniversary on Mars in August, has delivered some incredible finds to scientists back on Earth, including the discovery of solid evidence that ancient Mars could have supported life, according to NASA.

A key discovery has been uncovered at the rover’s landing site, called Gale Crater, where a long- since-dried-up lake once stood, said Wiens. “It’s the first time that we have seen lake sediments on Mars. It’s still really mysterious. The water was here a very long time ago, but there are some pieces that are telling us a lot.”

For example, scientists have found real clay minerals in the materials in the area that were probably sediments in the bottom of a lake, like those found on Earth, he said. “The surprising thing is this appears to be a freshwater lake. Previous discoveries of water on Mars appeared to be very briny. So here’s what we think was a fairly big lake that had fresh water.”

The ChemCam laser is operated half of the time by scientists at Los Alamos and half the time by scientists at the French national space agency, Centre National d’Etudes Spatiales (CNES) and at the French research agency, Centre National de la Recherche Scientifique (CNRS).

What’s been most surprising so far, said Wiens, is that on the laser’s very first firing on 19 August, 2012, it found evidence of hydration, or water, in the dust on Mars. “It’s still a mystery to us how this is present.” The water is in small quantities, however, making up only 1.5 to 3 percent of the content of the soil samples collected.

Future implications

That discovery, though, creates some interesting implications for future space travelers to Mars, he said. “If you would have astronauts there, they could potentially collect large amounts of soil, heat it up and get water,” said Wiens.

Asked if the scheduled 30-month mission is so far going like he expected, Wiens said it’s even more special than he dreamed. “It’s one thing to be planning for it, and then it’s another thing to have all the data and to have all the secrets that Mars has been revealing from all these spectral images that we have been collecting.”

NASA’s Jet Propulsion Laboratory, which designed and built the project’s Curiosity rover, manages the Mars Science Laboratory Project for NASA’s Science Mission Directorate in Washington, D.C. Since landing, Curiosity has so far sent more than 190 gigabits of data back to Earth, and has sent back more than 36,700 full images and 35,000 thumbnail images, according to NASA.

In July, the Curiosity rover began a long-awaited, 5-mile journey across the terrain of the red planet to begin exploring a rocky area known as Mount Sharp 11 months after the rover arrived on the planet’s surface following a 354-million-mile, eight-month voyage from Earth.

The Mount Sharp destination, which is in the middle of Gale Crater, is important to scientists working on the mission because it exposes many layers where scientists anticipate finding evidence about how the ancient Martian environment changed and evolved, according to the JPL. The rover is expected to take up to a year to reach Mount Sharp, due to the care that must be used in crossing the unknown terrain.

Shaler outrcop

At the end of June, it conducted a close-up investigation of a target sedimentary outcrop of rock called Shaler, according to NASA, then began heading away from Shaler on 4 July. The vehicle travels very slowly, initially traveling 59 feet away from Shaler that day, then adding another 131-foot excursion away from the site on 7 July.

In June, NASA released a spectacular 1.3 billion-pixel image of the surface of Mars, which was stitched together from almost 900 images taken by special cameras mounted on the Curiosity rover. The image can be explored using panning and scanning tools on NASA’s website. The images used to create the massive photograph include some 850 frames taken using the telephoto camera of Curiosity’s Mast Camera instrument, supplemented with 21 frames from the Mastcam’s wider-angle camera and 25 black-and-white frames from the on-board Navigation Camera, according to NASA.

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Originally published on eWeek.