Curiosity goes for a test drive
The Curiosity rover has taken its first drive today on Mars. It wasn’t much of a road trip. The unmanned craft went about 15 feet (4.57 m), turned 120 degrees and then reversed about 8 feet (2.43 m). Curiosity is now about 20 feet (6.09 m) from its landing site, now named Bradbury Landing after the late author Ray Bradbury. That may not seem like much, but it was a successful test of Curiosity’s mobility and takes it a step (or a roll) closer to beginning its two-year mission to look for areas where life may have or does exist on the Red Planet.
Curiosity has been compared to a nuclear-powered 4x4. With its radiothermal generators, it certainly is nuclear powered and at seven feet (2.1 m) long and a weight of 1,982 pounds (899.02 kg) it’s big enough, but that’s where the resemblance ends. The rover’s mobility system, as NASA calls it, is a scaled up version of the system used on the Sojourner, Spirit and Opportunity Mars rovers. It has six 20-inch (0.5 m) titanium-spoked aluminum wheels, each with its own electric motor and traction cleats to deal with rough terrain. All four corner wheels can be steered and all the wheels are mounted on a rocker-bogie system to keep them in contact with the ground regardless of how uneven the terrain.
Curiosity is not, however, built for speed. With a top speed of 0.085 mph (0.137 kph), it won’t break any records at the Nürburgring track, but its wheels put out very high torque to keep it from getting stuck in the sandy surface of Mars.
The test drive is the latest in the three-week shakedown that NASA and Jet Propulsion Laboratory engineers have been putting Curiosity through since its landing on August 6th. On Monday, JPL engineers tested Curiosity’s wheels in preparation for today’s drive and the first weather reports from the rover were made public. Temperatures at Bradbury Landing have varied from 28ºF to -103ºF (-2ºC to -75ºC). Unfortunately, two of Curiosity’s three wind sensors are inoperative and JPL suspects that debris kicked up on landing may have damaged them. In addition, Curiosity took a peek at the Martian soil by shooting a beam of neutrons at the ground, and recorded the backscattered radiation that resulted.
Also on Monday, Curiosity flexed its robotic arm for the first time. Though not as dramatic an episode as going for a spin, the arm is one of Curiosity's key systems. The 6.2-foot (1.88-m) arm has five degrees of movement and sports a formidable “hand” that weighs 73 pounds (33.11 kg). This hand is more properly referred to as a “turret” and contains a remarkable tool kit. The tools include a drill for boring into rocks and collecting powdered samples; an Alpha Particle X-ray Spectrometer (APXS); a sample processing subsystem called the Collection and Handling for In-Situ Martian Rock Analysis (CHIMRA), which is a sort of glorified scoop; the Mars Hand Lens Imager (MAHLI), which is a digital magnifying glass; and, the Dust Removal Tool (DRT), a kind of high-tech brush for sweeping dust off of rocks.
Once all the tests are complete and the green light is given, Curiosity will head for an area known as Glenelg on the first leg of a journey that will take it across twelve miles (19.3 km) of Martian desert. At least, that’s the official distance. Given how previous rovers have outlived their mission span, that could be just a start.
The video below is a NASA/JPL animation showing the stages of the Curiosity mission.