Mars Explorer

Fig. 3.14 Left. NASA Mars-Exploration-Rover (artist view courtesy NASA, JPL, Cornell). On the front side of the Rover the robotic arm carrying the Mossbauer spectrometer and other instruments can be seen in stowed position. Right, robotic arm before placement on soil target at Victoria crater rim, Meridian Planum, Mars. The Mossbauer instrument MIMOS II with its circular contact plate can be seen, pointing towards the rover camera. See also Sect. 8.3...

Fig. 8.27 NASA Mars-Exploration-Rover artist view (courtesy NASA, JPL, Cornell). On the front side of the Rover, the robotic arm (IDD) carrying the Mossbauer spectrometer and other instruments can be seen...

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...

Meteorites on Mars. Meridiani Planum is the first Iron meteorite discovered on the surface of another planet, at the landing site of the Mars Exploration rover Opportunity [359]. Its maximum dimension is 30 cm (Fig. 8.38). Meteorites on the surface of solar system bodies can provide natural experiments for monitoring weathering processes. On Mars, aqueous alteration processes and physical alteration by Aeolian abrasion, for example, may have shaped the surface of the meteorite, which therefore has been investigated intensively by the MER instruments. Observations at mid-infrared wavelengths with the Mini-TES... 

The miniaturized Mossbauer instruments have proven as part of the NASA Mars Exploration Rover 2003 mission that Mossbauer spectroscopy is a powerful tool for planetary exploration, including our planet Earth. For the advanced model of MIMOS II, the new detector technologies and electronic components increase sensitivity and performance significantly. In combination with the high-energy resolution of the SDD, it will be possible to perform XRF analysis in parallel to Mossbauer spectroscopy. In addition to the Fe-mineralogy, information on the sample s elemental composition will be obtained. 

KEYWORDS Mossbauer spectroscopy, MIMOSI la, Mars Exploration Rover, ln-situ resource utilization, X-ray fluorescence spectroscopy... 

Iron is one of the most abundant elements in the universe. Mossbauer (MB) spectroscopy is an established laboratory technique and a powerful tool to study Fe-bearing substances. The surface of Mars is Fe-rich compared to Earth, and a miniaturized MB spectrometer (MIMOS II) was developed for its robotic exploration as part of NASA s Mars Exploration Rover (MER) mission (Klingelhofer et al. 2003). 

A Follow-the-Water strategy has been adopted for Mars Exploration. Hoehler et al. (2007) suggested a Follow-the-Energy approach. The primary objective of the MER mission is to explore two sites on Mars where water may once have been present, and to assess past environmental conditions at those sites and their suitability for life (Squyres et al. 2003). 

Morris, R.V. et al. 2008. Iron mineralogy and aqueous alteration from Husband Hill through Home Plate at Gusev Crater, Mars Results from the Mossbauer instrument on the Spirit Mars Exploration Rover. Journal of Geophysical Research, 113, E12S42,... 

On 23 September 1999 the Mars Climate Orbiter,one of the missions in a long-tenn program of Mars exploration, birned out completely. 

It is obvious from these experiments that the absorption spectrum of the Martian red surface can be simulated reasonably well by a non-unique variety of Fe rich phases or their mixtures as can the weak magnetism, so that a positive identification will probably only be possible, following further in situ analyses and/or sample return and analysis in the lab.Two Mars Exploration Rovers (MERs) are due to arrive at Mars in 2004 and will attempt to analyze rocks and soils on the surface using several small spectrometers, including PanCAM (an extended visible region spectrometer), MiniTES (a thermal emission spectrometer), APXS (alpha proton X-ray spectrometer measuring the major elements), Mossbauer (run at current local temperature), as well as a 5-level magnet array similar to that on-board the Pathfinder Lander. 

The Mars Pathfinder rover (flight spare) pictured with one of the Mars Exploration Rovers (MER) during assembly. 

The Mars Pathfinder rover carried an Alpha Proton X-ray Spectrometer (APXS), and the two Mars Exploration Rovers (MER - Spirit and Opportunity) carried Alpha Particle X-ray Spectrometers (also called APXS, but in this case more precise versions of the Pathfinder instrument, though without the ability to monitor protons for light element analyses). These instruments contained radioactive curium sources (Fig. 13.16) whose decay produced a-particles, which irradiated target rocks and soils. The resulting characteristic X-rays provided measurements of major and minor element abundances. The MER rovers also carried Mossbauer spectrometers, which yielded information on iron oxidation state. 

The composition of Martian surface materials can be assessed using laboratory analyses of Martian meteorites, in situ APXS analyses from Mars Pathfinder and the Mars Exploration Rovers, and orbital geochemistry analyzed by GRS and derived from TES spectra. 

Bruckner, J., Dreibus, G., Gellert, R. et al. (2008) Mars Exploration Rovers Chemical composition by the APXS. In The Martian Surface Composition, Mineralogy, and Physical Properties, ed. Bell, J. F. Cambridge Cambridge University Press, pp. 58-101. 

All Mars rovers to date have carried alpha-particle X-ray spectrometer (APXS) instruments for chemical analyses of rocks and soils (see Fig. 13.16). The source consists of radioactive curium, which decays with a short half-life to produce a-particles, which then irradiate the sample. Secondary X-rays characteristic of specific elements are then released and measured by a silicon drift detector. The Mars Pathfinder APXS also measured the backscattered a-particles, for detection of light elements, but the Mars Exploration Rovers measured only the X-rays. 

While large commercial markets have been long in coming, aerogels have been used in NASA projects, such as Mars exploration vehicles and a space probe capturing comet-tail dust. 

Can this model published in 2003 (Marion et al. 2003a) explain all the geochemical findings of the 2004 Mars Exploration Rover (MER) missions Not exactly In our model we predicted that ferrous iron would precipitate as siderite (FeCOo) early in the temporal sequence, and siderite would ultimately be oxidized to ferric minerals such as ferrihydrite [Fe(OH)3] and hematite (FeoOo) (Fig. 5.10). There is no place in this conceptual model for the precipitation of ferrous or ferric sulfate minerals as suggested by the MER missions (Squyres et al. 2004 Lane, 2004). This problem could be simply rectified by drawing an arrow from siderite through the surface acidification... 

Figure 2 The Mars Exploration Rover Spirit s Mossbauer spectrometer. The hydroxyl containing mineral goethite (FeOOH) has been identified with this spectrometer in the Columbia Hills of Mars. This finding produced strong evidence for past water activity in the area that Spirit has been exploring. (Reproduced from web page with permission G Klingelhofer)...

These important questions will be addressed, at least in part, in future spacecraft missions. Two Mars Exploration Rovers, which are to arrive in early 2004, will carry a battery of instruments (Mossbauer, infrared, and visible spectrometers, APXS, microscopic imager, and a rock abrasion tool to remove dust and weathered coatings) that may analyze samples of the ancient crustal rocks... 

Perhaps we will learn more about this fascinating planet when the new NASA Odyssey mission and the two planned NASA Mars Exploration Rover missions launch and reach Mars in the next few years. 

The next scheduled lander mission to Mars, Mars Exploration Rover, is due to attempt touchdown in January, 2004. Twin Mars Exploration Rovers will land at separate locations using the Pathfinder-tested airbag... 

Jet Propulsion Laboratory. 2003 Mars Exploration Rover Mission. National Aeronautics and Space Administration. 

This launch of the Mars Exploration Rover Spirit in June 2003 propelled the robot to its successful touchdown on Mars in January 2004. 

This image of the Martian rock "Humphrey" shows a hole made by a grinding tool carried on the Mars Exploration Rover Spirit, which landed on Mars on January 4, 2004. The grinding process revealed the inner structure of the rock and produced a sample that could be tested for chemical composition. (NASA/JPL/Photo Researchers, Inc.)... 

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