Arm

Robotic Arm

The Robotic Arm holds and maneuvers the instruments that help scientists get up-close and personal with martian rocks and soil.

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Much like a human arm, the robotic arm has flexibility through three joints: the rover's shoulder, elbow, and wrist. The arm enables a tool belt of scientists' instruments to extend, bend, and angle precisely against a rock to work as a human geologist would: grinding away layers, taking microscopic images, and analyzing the elemental composition of the rocks and soil.

At the end of the arm is a turret, shaped like a cross. This turret, a hand-like structure, holds various tools that can spin through a 350-degree turning range.


Sample Equipment on the "Hand" (Turret)

At the tip of the arm is the turret structure on which five devices are mounted. Two of these devices are in-situ or contact instruments known as the Alpha Particle X-ray Spectrometer (APXS) and the Mars Hand Lens Imager (MAHLI). The remaining three devices are associated with sample acquisition and sample preparation functions:


Collection and Handling for In-situ Rock Analysis (CHIMRA)

This tool helps Curiosity sort rock materials collected by the rover's drill and scoop. It has a clamshell-shaped scoop to collect soil samples from the Martian surface. It also has a system of chambers and labyrinths used to sort, sieve, and portion samples. Curiosity sorts samples by changing the position of its "hand" (turret) while using a vibration device to move material through the chambers, passages, and sieves. The vibration device also creates the right portion size for dropping material into the inlet ports for rock-analyzing tools (SAM and CheMin).


Main JobAnalyze chemical elements in Martian rock and "soil" (regolith)
Location On the turret at the end of Curiosity's robotic arm
Size About the size of a cupcake
Size of Sampled Area About 1.7 cm in diameter when the instrument is in contact with the sample.
Upgrades Can operate day or night and takes about one-third of the time to process readings

Drill System

Curiosity uses this drill system to collect rock samples for in-depth analysis by two instruments inside the rover (SAM and CheMin). It can collect a sample from up to 2 inches (5 centimeters) beneath a rock's surface. The drill penetrates the rock and powders the sample to the appropriate grain size. The powder travels up an auger in the drill for transfer to sample processing mechanisms.


Main Job Collect and Process Samples for Analysis
Drill Type Rotary Percussive
Diameter of Drilled Hole 0.63 inch (1.6 centimeters)

Drill Bits

If the drill bit becomes stuck in a rock, the drill can disengage from that bit and replace it with a spare. Curiosity's arm moves the drill to engage and capture one of two spare bits in bit boxes mounted to the front of the rover.


Dust Removal Tool (DRT)

Curiosity uses this metal-bristle brushing device to remove the dust layer from a rock surface or to clean the rover's observation tray. Removing dust from rocks allows other instruments to analyze the structure and make-up of the rock. That information allows the mission team to understand if the samples come from rocks that either formed in water or were altered by it, and maybe even if organics, the chemical building blocks of life, are present!