Alpha Particle X-Ray Spectrometer (APXS)
The APXS on Curiosity’s robotic arm will identify chemical elements in rocks and soils. A pinch of radioactive material emits radiation that “queries” the target and an X-ray detector “reads” the answer. The instrument consists of a main electronics unit in the rover’s body and a sensor head mounted on the robotic arm. Measurements are taken by deploying the sensor head towards a desired sample, placing the sensor head in contact or hovering, and measuring the emitted X-ray spectrum for 15 minutes to 3 hours without the need of further interaction by the rover.
Mars Hand Lens Imager (MAHLI)
MAHLI is a focusable color camera on Curiosity’s turret. Researchers will use it for magnified, close-up views of rocks and soils, and also for wider scenes of the ground, the landscape, or even the rover. Essentially, it is a handheld camera with a macro lens and autofocus.
The investigation takes its name from the type of hand lens magnifying tool that every field geologist carries for seeing details in rocks. MAHLI has two sets of white light-emitting diodes to enable imaging at night or in deep shadow. Two other LEDs on the instrument glow at the ultraviolet wavelength of 365 nanometers. These will make it possible to check for materials that fluoresce under this illumination.
This camera uses a red-green-blue filter grid like the one on commercial digital cameras for obtaining a full-color image with a single exposure. It stores images in an 8-Gb flash memory, and it can perform an onboard focus merge of eight images to reduce from eight to two the number of images returned to Earth in downlink-limited situations.
Chemistry and Mineralogy (CheMin)
CheMin is one of two investigations that will analyze powdered rock and soil samples delivered by Curiosity’s robotic arm. It will identify and quantify the minerals in the samples. CheMin uses X-ray diffraction, a first for a mission to Mars. It supplements the diffraction measurements with X-ray fluorescence capability to determine further details of composition by identifying ratios of specific elements present. X-ray diffraction works by directing an X-ray beam at a sample and recording how X-rays are scattered by the sample at the atomic level.
A sample processing tool on the robotic arm puts the powdered rock or soil through a sieve designed to remove any particles larger than 0.006” before delivering the material into the CheMin inlet funnel. Each sample analysis will use about as much material as in a baby aspirin.
Sample Analysis at Mars (SAM)
SAM is designed to explore molecular and elemental chemistry relevant to life. SAM addresses carbon chemistry through a search for organic compounds, the chemical state of light elements other than carbon, and isotopic tracers of planetary change. SAM is a suite of three instruments: a Quadrupole Mass Spectrometer (QMS), a Gas Chromatograph (GC), and a Tunable Laser Spectrometer (TLS). The QMS and the GC can operate together in a GCMS mode for separation (GC) and definitive identification (QMS) of organic compounds.
SAM’s analytical tools fit into a microwave-oven-size box inside the front of the rover. While it is the biggest of the ten instruments on Curiosity, this tightly packed box holds instrumentation that would take up a good portion of a laboratory on Earth.
SAM’s sample manipulation system maneuvers 74 sample cups, each about one-sixth of a teaspoon in volume. The chemical separation and processing laboratory includes pumps, tubing, carrier- gas reservoirs, pressure monitors, ovens, temperature monitors, and other components.
Rover Environmental Monitoring Station (REMS)
REMS records six atmospheric parameters: wind speed/direction, pressure, relative humidity, air temperature, ground temperature, and ultraviolet radiation. All sensors are located around three elements: two booms attached to the rover Remote Sensing Mast (RSM), the Ultraviolet Sensor (UVS) assembly located on the rover top deck, and the Instrument Control Unit (ICU) inside the rover body.
Radiation Assessment Detector (RAD)
RAD will monitor high-energy atomic and subatomic particles reaching Mars from the Sun, distant supernovas, and other sources. These particles constitute naturally occurring radiation that could be harmful to any microbes near the surface of Mars or to astronauts on a future Mars mission. RAD is an energetic particle analyzer designed to characterize the full spectrum of energetic particle radiation at the surface of Mars. RAD’s measurements will help fulfill MSL’s key goals of assessing whether Curiosity’s landing region has had conditions favorable for life and for preserving evidence about life.
Dynamic Albedo of Neutrons (DAN)
DAN is an active/passive neutron spectrometer that measures the abundance and depth distribution of H- and OHbearing materials in a shallow layer of Mars’ subsurface along the path of the rover. DAN can detect water bound into shallow underground minerals along Curiosity’s path. It shoots neutrons into the ground and measures how they are scattered, giving it a high sensitivity for finding any hydrogen to a depth of about 20" directly beneath the rover.
Mars Descent Imager (MARDI)
During the final few minutes of Curiosity’s flight to the surface of Mars, the Mars Descent Imager (MARDI) recorded a full-color video of the ground below. MARDI is a fixed-focus color camera mounted to the fore port side of the rover, even with the bottom of the rover chassis. The camera took images at 5 frames per second throughout the period of time between heat shield separation and touchdown. Throughout Curiosity’s mission on Mars, MARDI will offer the capability to obtain images of ground beneath the rover for tracking of its movements or for geologic mapping.
Learn more about Curiosity’s science instruments at http://mars.jpl.nasa.gov/msl/mission/science. View the latest videos of the Mars Science Laboratory and Curiosity rover on Tech Briefs TV at www.techbriefs.com/tv/mars. Get the latest news on the MSL mission at www.nasa.gov/mission_pages/msl/.