Sensor head, Mars rover

Physically, the MIMOS II Mossbauer spectrometer has two components that are joined by an interconnect cable the sensor head (SH) and electronics printed-circuit board (PCB). On MER, the SH is located at the end of the Instrument Deployment Device (IDD) and the electronics board is located in an electronics box inside the rover body. On Mars-Express Beagle-2, a European Space Agency (ESA) mission in 2003, the SH was mounted also on a robotic arm integrated to the Position... 

Fig. 3.21 Example of temperature variation as measured by MIMOS II temperature sensors on MER (i) inside the rover body at MIMOS electronics board (black curve), (ii) outside the rover, at the MIMOS II SH (green and red curves), which is at ambient Martian temperature (a) inside the sensor-head, at the reference absorber position (green), (b) outside the SH at the sample s contact plate (red). Temperatures at the two SH positions are nearly identical (difference less than 2 K). During data transmission between the rover and the Earth (or the relay satellite in Mars orbit) the instrument is switched off resulting in immediate small but noticeable temperature changes (see figure above)...

Fig. 8.28 External view of the MIMOS II sensor head without contact plate assembly (left) MIMOS II sensor head mounted on the robotic arm (IDD) of the Mars Exploration Rover. The IDD also carries the a-Particle-X-ray Spectrometer APXS, also from Mainz, Germany, for elemental analysis, the Microscope Imager MI for high resolution microscopic pictures ( 30 pm per pixel), and the RAT for sample preparation (brushing grinding drilling (< 1 cm depth)). Picture taken at Kennedy-Space-Center KSC, Florida, USA...

Figure 12.16 Alpha particle X-ray spectrometer (APXS). To determine the elemental composition of rocks and soils of Martian surface, the rovers, which landed in 2004 on Mars, carry a deployment device that could be in contact with the rocks. The sensor head contains six Cm radioactive sources, six alpha detectors and one X-ray detector in the centre. The accumulation time is a few hours per sample analysed.

Figure 12-1. Tb shows the sensor head from the Mars rover missions of 2(K)4. The head contains a curium-244 source that emits X-rays and 5.81 MeV alpha particles. The X-rays cause fluorescence in Martian rock samples, and the alpha particles stimulate X-ray emission as well. X-ray emission stimulated by bombardment by alpha and other subatomic particles such as protons is called punicle induced X-ru emission, or I lXE. llie X-ray detector is a new room-temperature type, which in the low temperature of the Martian night (below 4U°C.) exhibits low noise and high signal-to noise ratio for excellent resolution and sensitivity. Note the concentric design of the sensor head with six (im-244 sources arranged around the central detector. The X-ray spectrum of Figure 12-14 was acquired with the sensor head.

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