APXS instrument - Canada's contribution
Roughly the size and shape of a Rubik's cube, APXS's sensor can gather data day and night. It takes two to three hours to analyze a sample to determine what elements it is made of, including trace elements. A quick-look analysis can be completed in about ten minutes. APXS, which sits on the end of the rover's robotic arm, is placed close to a sample and bombards it with alpha particles (charged Helium nuclei) and X-rays to study the properties of the energy emitted from the sample in response. The APXS instrument on Curiosity is an updated version of the spectrometers that were successfully used on the Mars Exploration Rover (MER) and Mars Pathfinder missions.
APXS on Curiosity
APXS's components during vibration tests at MDA's laboratory in Brampton, Ontario. (Credit: MDA)
The APXS spectrometer will be installed at the end of Curiosity's robotic arm with four other instruments that will probe the rocks and soil of Mars. (Credit: NASA/JPL-Caltech)
A close-up of APXS's sensor head as it undergoes vibration tests at MDA in Brampton, Ontario. The sensor head is the part of the instrument that will be placed into contact with Martian samples for analysis. (Credit: MDA)
In the same way that a new vehicle gives off a distinctive "new car smell" due to the slow release of gasses, the new materials used to build space science instruments can also emit gasses that could potentially interfere with science results. Here, APXS's sensor head and calibration target (hidden) are being heated gently in an outgassing chamber at NASA's Jet Propulsion Laboratory (JPL) on November 18, 2008, to ensure that any "new space instrument smell" is within acceptable limits. (Credit: NASA/JPL)
APXS's sensor head and calibration target during functional testing upon arrival at NASA's Jet Propulsion Lab (JPL) on November 18, 2008. (Credit: NASA/JPL)
The 3 components of the Canadian-built APXS (from left to right): the sensor head, calibration target and main electronics unit. (Credit: MDA)
The sensor head on the APXS was installed during testing at NASA's Jet Propulsion Laboratory (JPL), in California. The sensor head is roughly 8 centimeters high. (Credit: NASA/JPL-Caltech)
Nicholas Boyd (left) and Ralf Gellert (right), the Principal Investigator for APXS, prepare the instrument for the installation of the sensor head during testing at NASA's Jet Propulsion Laboratory (JPL) in California. (Credit: NASA/JPL-Caltech)
The suspension system on rover Curiosity was tested at NASA's Jet Propulsion Laboratory (JPL), in California. (Credit: NASA/JPL-Caltech)
APXS is accompanied by nine other science instruments on Curosity, including a hand lens imager and a panoramic camera. In comparison, the MER mission (known for its famous rovers, Spirit and Opportunity) had only five instruments on each rover. The size of a small car, the Curiosity rover is also much bigger than its predecessors. Curiosity is an effective amalgamation of state-of-the-art laboratory instruments and MER-style mobility that will enable Curiosity to roam and explore the planet.
Due to the added capabilities and the big instruments in the rover's belly, Curiosity needs more energy to operate. It receives its energy from a thermoelectric generator that uses the decay heat from radioactive isotopes to generate about three times the amount of energy that a MER rover achieved under ideal conditions with its solar panels. This also means that Curiosity is able to operate much better during the Martian winter, when the capabilities of the MER rovers were curtailed due to the low-standing sun.
The mission should last at least one Martian year, the equivalent of two Earth years. As with its predecessors on this desert planet, Curiosity is sleuthing through the dust and rock historical archive of Mars' ancient environment in search for answers to a question that has fascinated humanity for ages: is there life out there in the Universe? Canada's APXS instrument will help scientists get a clearer picture of the answer.
The Canadian Space Agency (CSA) is an international partner on NASA's Mars Science Laboratory mission, led by the Jet Propulsion Laboratory (JPL). Dr. Ralf Gellert of the University of Guelph is the Principal Investigator for APXS (Alpha Particle X-ray Spectrometer). He provided the scientific design based on the Mars Exploration Rover (MER) instrument (developed at the Max Planck Institute for Chemistry, in Mainz, Germany) and leads the APXS science team, which includes: the University of New Brunswick, University of Western Ontario, JPL, University of California, San Diego, Cornell University, the Rensselaer Polytechnic Institute and the Australian National University. MacDonald, Dettwiler and Associates Ltd. (MDA) is the prime contractor for APXS.
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