Mars express

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... 

Ice has been found at the poles new measurements of Mars southern polar region indicate the presence of extensive frozen water. The polar region contains enough frozen water to cover the whole planet with a layer of liquid approximately 36 ft deep. A joint NASA-Italian Space Agency instrument on the European Space Agency s Mars Express spacecraft provided these data (NASA press release, 15 March 2007). It must be assumed that volcanic exhalations contained large amounts of water. 

Fig. 3.1 Perspective view of part of the caldera of Olympus Mons on Mars. This view was obtained from the digital altitude model derived from the stereo channels, from the nadir channel (vertical perspective) and the colour channels on the Mars Express Orbiter. The photograph was taken on 21 January 2004 from a height of 273 km. The vertical face is about 2.5 km high, i.e., about 700 m higher than the north face of the Eiger mountain (Switzerland). With permission of the DLR...

Free water, the essential precondition for life as we know it, has recently been detected on Mars images taken by the high resolution stereo camera (HRSC) on board ESA s Mars Express spacecraft show a patch of water ice on the floor of an unnamed crater near the Martian north pole. Geomorphic studies indicate that the surface of Mars can be divided into two types (Jaumann et al 2002) ... 

On June 2, the ESA space vehicle Mars Express with its lander, Beagle, was launched and landed on Mars on December 23 however, contact with Beagle was not possible. 

The layers of sediment at the Martian south pole do not consist of pure ice they are interspersed by layers of dust. The latest data were obtained by the Mars Advanced Radar for Subsurface and Ionospheric Sounding apparatus (MARSIS) on board the Mars Express Orbiter. The radar waves from the instrument pass through the ice layers until they reach the base layer, which can be at a depth of up to 3.7 km. The distribution of the ice at the south pole is asymmetric, and its total volume has been estimated to be 1.6 x 106km3 this corresponds to an amount of water which would cover the whole planet with a layer 11 metres deep (Plaut et al., 2007). 

Bibring, J.-P., Langevin, Y., Gendrin, A. et al. (2005) Mars surface diversity as revealed by the OMEGA/Mars Express observations. Science, 307, 1576-1581. 

Often this consists of a dual architecture around the bus and the computers. However, some variations can meet the needs and specific constraints of such missions such as the complexity of navigation and the criticality of certain phases. For example, the European probes Mars Express, Venus Express and Rosetta have two computers in each channel. In principle one is dedicated to data management and the other to the navigation and attitude and oibit control system, but the architecture enables the use of aity subset of all four computers, even the four in hot redundancy, for critical phases depending on the phases of the mission. In addition, there are four reconfiguration modnles, which can be used in different secondary schemes, up to four hot redundant (in vote two out of four in the sense that a reconfiguration is done when it is decided by at least two modules). 

European planetary missions such as the Rosetta spacecraft in 2003, the Mars Express in 2003, and the BepiColombo Mercury planetary orbiter planned for July 2016... 

Another way to free the mirror carriage from the high precision requirement is to use retroreflectors instead of flat mirrors. Then a small tilt of the reflector does not matter. The original instrument of Fellgett used comer cubes. High precision requirements are shifted from the motor design to that of the reflector, where they are easier to handle, but are still not trivial. The Cassini spacecraft (to arrive at Saturn in July 2004) and the Mars Express spacecraft (to arrive at Mars in December... 

At this point, it is also appropriate to mention the Composite Infrared Spectrometer (CIRS) on the Cassini spacecraft, that flew past Jupiter in December 2000 and will arrive at Saturn in July 2004, and the Planetary Fourier Spectrometer (PFS) on the Mars Express spacecraft, to arrive at Mars in December 2003. Both spectrometers are dual channel instruments consisting of short- and long-wave interferometers. First, we discuss CIRS. 

Many measurements were made to determine the content of water vapor in the atmosphere of Mars. Some examples are the MAWD (Mars Atmospheric Water Detector) on board of Viking 1 and Viking 2 orbiters or measurements made with Mars Global Surveyor Mission and Mars Express. Very often the IR band about 1.38 pm was used. Such measurements are important input factors for understanding the annual water cycle on Mars. For example Fedorova et al., 2010 [128] report on Viking observation of water vapor on Mars explaining some discrepancies of the results obtained by different instruments. 

Fig. 3.10 Mars crater with deposits of water ice. Credit Mars Express mission...

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