In its first month on Mars, NASA's rover Curiosity has traveled a grand total of 357 feet, briefly flexed its robotic arm, with its mother lode of instruments where a hand would be, and now it's time to stop for what researcher Aileen Yingst calls a bit of Martian tai chi.
Over the next week, engineers will put the robotic arm – shoulder, elbow, wrist, and instrument turret – through a more rigorous set of movements that will allow engineers to tailor the arm's motions to less gravity than it experienced during tests on Earth.
And then, it's on to Glenelg – a spot another 1,100 feet away that researchers are eager to reach. It lies at the confluence of three geological formations, some of which may hint at the presence of liquid water in the crater early in the planet's history.
Thus, rocks there may bring Curiosity one step closer to answering the question the mission aims to address: Did Gale Crater and its central mountain, Mt. Sharp, once host an environment that microbial life might have found to its liking?
Before Curiosity makes its halting beeline for Glenelg, however, the coming week's tai chi sessions need to get the sag out of Curiosity's arm, explains Matt Robinson, the lead engineer for arm testing and operations.
On Earth the arm weighs more than 150 pounds and sports a 73-pound turret on the business end. The turret hosts two instruments – a camera that serves as a geologist's magnifying glass and a spectrometer that uses x-rays and alpha particles to analyze the chemical make-up of rocks. In addition the turret also sports a drill, a dust-removal tool, and hardware to scoop soil and drill samples and send them to chemistry labs inside Curiosity's body.
The arm operates based on angles controllers want the various joints to form in order to put instruments gently on their rocky targets. But Mars has only about 38 percent of earth's gravity, meaning that the computer controlling the arm has to learn how to live without the sag the arm experienced on Earth.
As the arm goes through its paces, researchers will position the spectrometer and the Mars Hand Lens Imager so that they can make fine adjustments to the instruments as they are aimed at calibration targets on Curiosity's chassis.
The process is not for the impatient.
Researchers using the Mars Hand Lens Imager just got back their first pictures of the instrument, which was exposed to the dust-up from the rover's unique "sky crane" landing system. The lens, protected by a dust cover, is designed to spot dust grains as small as talcum power.
"So far, so good," pronounced Ms. Yingst, the deputy lead scientist for the imager.
But "there is a downside to being involved in landed operations" instead of the entry, descent, and landing (EDL) portion of the mission, she said during a briefing at NASA's Jet Propulsion Laboratory in Pasadena on Thursday. "For EDL you get seven minutes of terror. For landed operations for those of us on some of these instruments, it's more like 30 sols of terror." (A sol is one day on Mars.)
Once Curiosity's week of tai chi ends, mission planners aim to send the rover to Glenelg on what is likely to be a trip of two to three weeks.
Along the way, the team will be on the lookout for fine-grained rocks on which they can test the alpha-particle x-ray spectrometer on the turret as well as ChemCam, a laser-based spectrometer and camera located atop Curiosity's mast. Both take complementary measurements in which the whole picture they present is more detailed than each can provide alone. And researchers will be looking for something loose and scoop-worthy that they can load into Curiosity's internal chemistry labs.
Once Curiosity finishes at Glenelg, it's off on the 5-mile trek to the base of Mt. Sharp for the main exploratory show. If Curiosity traveled at a brisk pace of about 330 feet a day, with no detours, slowdowns for iffy terrain, or stops along the way, it could reach the mountain in just under three months.
But if the path has intriguing way points, as researchers anticipate, the journey could take upwards of a year, says Joy Crisp, deputy project scientist for the mission.