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6 août 2012 1 06 /08 /août /2012 12:23

 

#1 - It's really big!

 

The Curiosity rover is much larger than the previous rovers (Spirit and Opportunity): 3 m in length and weighs 900 kg, about the size of a MINI Cooper.

 

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Its weight enable Curiosity to travel longer distance, overcome larger obstacles and carry an impressive payload of scientific instruments. Which leads to the 2sd awesome thing about Curiosity :

 

#2 - It's a fully equipped science laboratory!

 

It's aptly named Mars Science Laboratory (MSL). Indeed, it carries a dozen of high-tech scientific instruments :

 

A bunch of cameras : 

  • Mast Camera (MastCam): A Medium Angle Camera (MAC), which has a 34 mm focal length (22 cm/pixel) and a Narrow Angle Camera (NAC), which has a 100 mm focal length (7.4 cm/pixel). Both cameras have a RGB Bayer pattern filter (for color images) and an 8-position filter wheel.
  • MARDI (MARs Descent Imager) was programmed to take color images during the descent to the Martian surface.
  • A Camera microscope, Mahli (MArs Hand Lens Imager), with a resolution of 15 microns per pixel, equipped with both white and ultraviolet LED illumination for imaging in darkness and fluorescence imaging to detect traces of organic molecules.
  • Two pairs of black and white navigation cameras (Hazcams) located on the four corners of the rover for safe positioning of the robotic arm. The cameras use visible light to capture stereoscopic 3D imagery.
  •   A pair of black and white navigation cameras mounted on the mast to support ground navigation (Navcams).

 

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1743112 3 7820 image-du-mont-sharp-montagne-de-5-000-metres

 

 

Many instruments design to detect traces of water (i.e. hydrated minerals and adsorbed water in the soil) and/or organic molecules (i.e. life forms) :

  • ChemCam (Chemistry and Camera)  a laser-induced breakdown spectroscopy (LIBS) system  . A pulsed LASER target a rock or soil sample, causing the fusion of rock and generating a plasma. Light desexcitation of this plasma is captured by an optical fiber and analyzed by  the ChemCam spectrometer.
  • APXS (Alpha-Particle-X-ray Spectrometer) irradiate samples with alpha particles (helium nucleus) and detect the re-emitted X-rays and protons for determining the elemental composition of samples, i.e. Particle-induced X-ray emission  . It operates using 244 currium as a source of alpha particles and can analyse many elements in the soil (Sodium, magnesium, silicon, aluminium, sulfur and heavy elements).
  •   CheMin (Chemistry & Mineralogy) : an XRD (X-Ray Diffraction) and XRF ( X-Ray Fluorescence) detector gives respectively the crystal structure and the mass concentration of the different elements.
  • An   active/passive neutron spectrometer  : DAN (Dynamic Albedo of Neutrons) measures the abundance and depth distribution of protons (e.g., adsorbed water, hydrated minerals) in a shallow layer (~1 m) of Mars' subsurface along the path of the rover. In active mode, DAN measures the time decay curve (the "dynamic albedo") of the neutron flux from the subsurface induced by its pulsing 14 MeV neutron source.   
  • An awesome miniature analytical chemistry lab called  SAM (Sample Analysis at Mars) : gas chromatography (with 6 columns), quadrupole mass spectrometer and tunable LASER spectrometer, connected to a sample preparation system (74 micro-ovens, grinders and mixers...)  .
  • A radiation detector, RAD (Radiation Assessment Detector), which includes a photodiode detector (PIN junction), cesium iodide calorimeter  and a plastic scintillator. This is the kind of detector you can find in the LHC or the  AMS-02 satellite to detect elementary particles and gamma rays. The main purpose is to determine the viability and shielding needed for potential human explorers.
  • Finally, Curisity has its very own weather station, REMS (Rover Environmental Monitoring Station), which measures pressure, humidity, UV radiation, wind speed, soil temperature and the air.


 

 

Drawing-of-the-Mars-Science Laboratory

 

 

 

 

Of course all these scientific instruments need some power, and that brings us to the 3rd awesome thing about Curiosity :

 

#3 - It's nuclear power

 

Of course it's not fission or fusion power, it's a radioisotope thermoelectric generator (RTG) that produce electricity from the natural decay of plutonium-238. Heat given off by the natural decay of this isotope is converted into electricity, providing constant power during all seasons and through the day and night, and waste heat can be used via pipes to warm systems.

 

#4 - The landing system

 

Although some previous missions used airbags to cushion the shock of landing, Curiosity rover is too heavy for this to be an option. The engineers came up with a novel alternative solution: the sky crane system :

 

 

# 5 - Easter eggs

 

It takes about 14 minutes for radio waves to travel from the mars to earth. Therefore, there is a 30 minutes delay between the driving command and finding out the result of the rover's move. The driver, back on earth, needs to check the distance it has travelled and this is done by counting of a repeated tread pattern imprint by the wheels. Engineer of the Jet Propulsion Laboratory chose as pattern their own acronym (JPL) in Morse Code.  

 

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Curiosity rover writes Morse Code of JPL everywhere it goes

 

 


 

CNRS : La suite intrumentale Sample Analysis at Mars (SAM)

JPL : MSL Science Corner

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