Last year on the former "God and Nature" blog, we published a feature about the life and work of Roger Weins, an ASA member and scientist at Los Alamos National Laboratory. He’s also P.I. of the NASA Curiosity rover’s “ChemCam,” a laser gun that’s vaporizing rocks for identification on Mars. We caught up with Roger for an update on how the project is going and what it’s like behind the scenes of the Curiosity mission.
Life’s been quite a blur for Roger Weins since we last spoke.
His voice sounds faintly weary over the phone as he tells me the pace of work for his team has increased by a factor of two or more since the $2.5 billion Mars Science Laboratory Mission touched down safely in early August.
“It’s been 54 days since the landing,” Roger said.
“54 days,” I repeated, marveling.
“No—wait a minute.” Roger jumped to life, “It’s been 55 earth days. Sorry. We’re operating on slightly longer timescales here at JPL [NASA’s Jet Propulsion Laboratory in Pasadena, CA], since Mars rotates about 40 minutes slower than Earth.”
Roger and his team work through the night on Mars, because that’s the best time to analyze what the rover did during its eight hours of operation the previous day. “We don’t operate Curiosity at night,” Roger says, “we could, but nights on Mars get down to negative 200 degrees, and it’s better to be moving when the sun can warm the rover’s joints and wheels. So we use the night hours to look at data and write new commands.”
ChemCam, Roger's primary project for the past few years, is the first instrument ever 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 small, efficient laser Roger and collaborators in France and the U.S. developed can analyze an area up to twenty feet away without any physical touch besides its pulsing beam of photons.
As these pinpoint-focused beams zap the surface of a rock, they excite atoms within it, which 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.
“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 told me a year ago. “ChemCam is able to analyze the presence of elements like carbon, nitrogen, oxygen, and hydrogen, the ‘building blocks’ of life, as well as take higher resolution 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.”
The mission has already amassed several gigabytes of data, and found some interestingthings, but it’s a lot to process. “You can’t just joystick a vehicle on Mars,” Roger reminds. On a regular shift for his team in Pasadena, two members begin work by checking the health of the instruments and taking inventory of what they asked the machine to do, then downloading and processing the data into more useable form for further analysis. They then give a report to the team on whether the activities were successful, and a group of scientists decide what to do next based on what they see and how much time is available on the rover the next day. After they recommend these activities, another team builds the software commands needed to turn the mast a certain direction, fire the laser, or take pictures.
The information being radioed to and from Curiosity is most often relayed by two satellites that fly over Gale Crater at heights of 160 to 250 miles, eliminating the need for the rover to spend extra energy sending a signal all the way to earth. This system also allows scientists to communicate more frequently with their machines, rather than having to wait for a direct line.
“On our team, there are 40 people; 20 U.S., 20 French, half of them engineers, half scientists. A few of us have overall responsibilities,” Roger says. “My job is to oversee the project and make sure everyone is getting along well. Relations have been fabulous so far, although sometimes I have to send people home so they don’t get sick or desert their families…”
Roger chuckles, but it has been taxing. “I spend about two thirds of my time at JPL. It’s pretty much go, go, go, right now. Because of the extra 40 minutes Mars takes to rotate, shifts have been occurring later and later in the day. I eat, sleep, call home, work—well, I hate to call it work—I explore…”
After they’ve been together for three months at JPL, the bi-national ChemCam team will go back to operating from two different stations, one in France, one in New Mexico.
Overall, Roger says he is pleasantly surprised that the Curiosity mission has worked out so well—from a tremulous yet well executed landing to some fascinating early days. “I was working on another mission to Mars that crashed, the Genesis mission, and the difference is night and day,” says Roger.
In closing, I asked Roger whether he had any thoughts or reflections that might especially resonate with the members of the ASA and CiS.
Roger paused for a moment, then said, “You know, working on this planet, you really start to place yourself into the ‘eyes and ears,’ so to speak, of the rover, itself. On Mars, a planet that’s empty of life—no plants, no animals, no humans—a place that’s completely uninhabited… Well, that’s a strange feeling. The sun rises and sets on a roughly 24-hour schedule, and there’s wind blowing—and yet, there’s nobody there. It’s really a strange feeling to realize in this way how special our earth really is.”
