Shooting the Red Planet

Mars as seen through the Hubble Space Telescope.

If the old expression “shooting the moon” means taking on a risky challenge, just imagine what “shooting Mars” might imply.

Perhaps even more than that heavenly body illuminating our nightly strolls and tugging on ocean tides, Mars looms large in our collective imagination. Pictures of the red planet liven up the walls of almost every grade school science classroom in the country. There’s no dearth of movies, cartoons, and novels in which bulbous-headed Martians descend to Earth in coin-shaped ships to help us humans achieve our own demise.

And when we wander outside of night-sky-dulling city lights, we often see Mars with our own eyes — although most of us mistake its rubicund glow for a brighter-than-average star.
Even when he was a little boy, ASA scientist Roger Wiens wouldn’t have made that mistake. For him, Mars isn’t as much a distant, alien object as it is an old acquaintance. He knows where it lies on a map of the skies at any point in the calendar year, and could probably draw a pretty accurate map of the surface of Mars, itself.

Roger grew up in an exciting time for stargazers and aspiring NASA scientists, especially those with an affinity for the red planet. Roger’s interest was ignited along with the Mariner 9 mission, the first spacecraft to ever orbit Mars, and grew when the planet passed closer to earth than it had in many years.

But unlike the majority of kids who lit out for the nearest field at night with a telescope in tow, Roger’s red planet passion followed him past adolescence — pushed him, even, to where he is now: leading the team of researchers at Los Alamos National Laboratory that just put the finishing touches on a machine that’s being taken to Mars.??The rock-vaporizing, element-identifying laser gun that Roger and his team developed will be an important part of the Mars Science Laborator rover, Curiosity, scheduled to launch this fall. Their instrument, called the ChemCam (, will be “interrogating” its Martian home by boring through the dust and outer layers of rocks on the planet’s rusty surface and analyzing their composition.

The Curiosity rover, on the red planet with ChemCam, starting in 2012 (NASA/JPL/Caltech).

“Knowing just what a rock is made of and what other types of rocks are around it can tell you a lot about the conditions in which it formed,” says Roger. “It’s pretty clear that Mars was full of water at one time, but the planet has been relatively dormant for billions of years. We’re trying to understand what the environment of Mars was like in the distant past, including whether life ever developed there, by doing just what we do on earth when we’re searching for ancient life forms — looking under the surface.”

Roger added, “ChemCam will be able to analyze the presence of elements like carbon, nitrogen, oxygen, and hydrogen — the ‘building blocks’ of life, as well as take higher resolution, close-up images of Martian rocks than any camera NASA has yet deployed. The surfaces of these rocks, the grooves and knobs and bumps on their faces, give us clues as to whether they formed in the presence of water.”

Artist depiction of the ChemCam instrument interrogating a rock outcrop on Mars.

ChemCam is the first instrument being taken to Mars that can actually determine the elemental composition of rocks without having to deploy an arm or use scooping and grinding mechanisms, which are energy-depleting and wear down over time. Instead, the laser Roger and collaborators in France and the U.S. developed can point to an area of interest up to twenty feet away without any physical touch besides its pulsing beam of photons.

As these pinpoint-focused light beams zap the surface of a rock, they excite atoms within it and emit light of different colors depending on what elements are present. This light is seen by a telescope that’s built into ChemCam, which then transfers the colored light, or spectra, through an optical fiber into the body of the rover. Inside the rover, a spectrometer sees the colors as if they were flags representing the elements themselves.

“Every element has its own associated wavelengths of light,” Roger explains. “If you think about the distinctly yellow color of sodium vapor streetlamps, you’ll get the idea. Those streetlamps look yellow because that’s the wavelength at which sodium fluoresces. So if there were sodium in our sample, it would appear as a thin yellow line among many other colored lines in the spectrum, each one telling us something about the elements that make up the rock.”

The ChemCam project first entered Roger’s mind over ten years ago when a colleague at Los Alamos Lab gave a demonstration of a laser technique similar to the one he and his team later built for Curiosity. In the past, Roger had done research on the chemical make-up of Martian meteorites as well as of particles in solar wind, so when he saw a laser the size of a cigar powered by a 9-volt battery cause a spark on a sample across the room, he knew the technique could be developed for use on another planet.

The Curiosity rover touches down on Mars almost nine months after lifting off. For the makers of the many machines that comprise Curiosity, that pregnant wait will be well worth it when the lab opens its shutters to the Martian landscape for the first time.

Dr. Wiens and instrument manager Bruce Barraclough don protective goggles as they prepare to test ChemCam’s laser (LANL photo).

“It’s been so exciting to see the ChemCam finally perform exercises and collect data,” says Roger. “I can hardly imagine what the feeling in our lab will be a year from now, once Curiosity starts sending information back from Mars.” Roger has already given special lectures on Mars and on the ChemCam instrument in a number of countries and across the US.

While much of that data will be used to determine what Mars looked like in its youth, NASA scientists are also keen on learning what might still be lurking just below reach of past Mars rovers and of Curiosity, itself.

Giving an interview with BBC Radio during the landing of NASA’s GENESIS capsule.

“We’re taking baby steps,” says Roger. “We won’t be able to explore more than a few inches deep for quite some time, maybe not until we actually put a human on Mars. But data taken by ChemCam will also be instrumental in planning for a human mission, since we need to know what astronauts can expect when they get there, like whether the soil is toxic and where to look for water.”
In terms of challenges, imagining a future in which we humans stride across Mars might be quite a stretch for some. But it was the same for folks at the turn of the last century who, shifting their gaze to the moon, simply assumed it was unreachable.

Roger embraces Christianity, which he sees as a statement of scientific humility. Just over a century ago the Physics community had a strong sense that there was relatively little left to discover. A statement widely attributed to Lord Kelvin at that time implies that the only remaining job of science was to make increasingly precise measurements. Roger points out that little more than a hundred years later we already see how wrong that idea was! The existence of galaxies, the big bang, nucleosynthesis, relativity, quantum mechanics and band-gap theory of semiconductors, the structure of DNA and the human genome were all unknown at the time of these statements.

Projecting a century from now, who knows what new dimensions, either literally or figuratively, will be discovered? So while science needs to remain skeptical of things not yet proven, it also needs to remain humble and open to what the future will illuminate.
Roger points out that the new discoveries of the 20th century, such as the ancient age of the Earth and human origins, also influence our understanding of scripture, just like the discoveries of the previous centuries caused people to abandon archaic ideas like the geocentrism or “the firmament” and heaven as physical locations in our three-dimensional sky. “But the core message of scripture is timeless. It still gives the best description of the human condition and of how we ought to live,” Roger adds.

Roger feels that his involvement in science hasn’t just been the result of lucky coincidences — rather, he senses the hand of God’s providence in his work. For those Christians who grow nervous seeing once-deep mysteries laid open by scientific study, Roger feels sympathy as well as a desire to help them appreciate the glory of God more fully throughout creation — which, of course, extends beyond our own horizon.

Roger and his wife, Gwen, pose in front of an instrument display in the cleanroom (LANL photo).

As such, Roger is the author of a well-read paper on radiometric dating and the ancient age of the Earth from a Christian perspective (one of the first such writings to be published online) that is available on ASA’s website at He’s also working on a book about his experiences in space called Getting to Mars.

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