Martian surface temperatures

MIMOS II has three temperature sensors one on the electronics board and two on the SH. One temperature sensor in the SH is mounted near the internal reference absorber, and the measured temperature is associated with the reference absorber and the internal volume of the SH. The other sensor is mounted outside the SH at the contact ring assembly. It gives the approximate analysis temperature for the sample on the Martian surface. This temperature is used to route the Mossbauer data to the different temperature intervals (maximum of 13, with the temperature width software selectable) assigned in memory areas. Shown in Fig. 3.21 are the data of the three temperature sensors taken on Mars (rover Opportunity at Meridiani Planum) in January 2004 between 12 10 PM on Sol 10 (10 Martian days after landing) and 11 30 AM on Sol 11. The temperature of the electronics board inside the rover is much higher than the temperatures inside the SH and the contact plate sensor, which are nearly identical and at ambient Martian temperature. 

MIMOS II has three temperature sensors, one on the electronics board and two on the sensor head. One temperature sensor in the sensor head is mounted near the internal reference absorber, and the measured temperature is associated with the reference absorber and the internal volume of the sensor head. The other sensor is mounted outside the sensor head at the contact ring assembly. It gives the analysis temperature for the sample on the Martian surface. This temperature is used to route... 

The discovery of homochirality on a planet such as Mars could be an excellent biomarker and strengthen the argument for life on Mars. With an EE in the solar nebula there should be an EE on the surface of Mars of order 9 per cent but remains of ancient life on Mars would show a greater excess. The interchange of enantiomers occurs naturally in a process called racemisation and for the most labile amino acid, aspartic acid, the half-life for the racemisation is 800 years at 300 K in 800 years, half of the non-biotic aspartic acid would racemise and the EE would go to zero. In dry conditions, however, the half-life is much longer, perhaps as large as 5 x 104 years at 300 K. Extrapolation of the racemisation rate to 215 K, the equatorial temperature of Mars, extends the half-life further to 3 x 1012 years and to 1027 years at 150 K, Martian polar temperatures. Hence, discovery of a considerable EE in the Martian soil would be a strong indicator of ancient Martian life. 

Mars is almost free of clouds and the surface can be seen from the earth through a telescope. The results of the recent space probes (1073a) reveal that the surface temperature ranges from 188 to 243 K and the Martian poles are composed of substantial amounts of water ice, seasonally covered by C02 frost. The rusty-red color of the surface is caused by the presence of substantial amounts of iron oxides. The mean surface atmospheric pressure is 7.65 0.1 mbar. The temperature profile of the Mars atmosphere is given in Fig. VIII— 12. 

If Soln. E is allowed to dry by evaporation at 0°C (Fig. 5.14c) or freezing to the eutectic (Fig. 5.14d), then the distribution of precipitated salts is similar to Soln. C except for the large increase in MgSC>4 salts (cf. Figs. 5.14a,b with 5.14c,d). Exactly the same suite of salts precipitate for Solns. C and E. Also, the eutectic temperature is the same (—35.4°C). For Soln. E, the salt quantities fall in the order (MgNa)SC>4 > NaCl > (MgCa)CC>3, in agreement with estimates of salt distribution on the Martian surface (Clark and Van Hart 1981). 

Recently it has been proposed to make use of the greenhouse potential of CFC for the ferraforming of Mars [32b]. Addition of a four hundreds parts per billion (ppb) to the Martian atmosphere would lead to a 70 K increase of its surface temperature. 

The atmosphere on Mars is composed mainly of carbon dioxide. The surface temperature is 220 K and the atmospheric pressure is about 6.0 mmHg. Taking these values as Martian STP, calculate the molar volume in liters of an ideal gas on Mars. 

A modified version the Li-SOCl2 system was used for Mars Microprobes as part of the Mars Surveyor Lander Mission (1998). Due to high impact the probes were to encounter during landing and penetration and the ultra-low temperature the aft-bodies were to experience on the Martian surface, the batteries needed to be tolerant to high impacts of 80,000 g and operate at temperatures of —80 C. The low-temperature performance was improved with the use of lithium terachloro gallate salt and with a reduction in the salt... 

In order for ecopoiesis to be possible, four principal modifications must be applied to the Martian environment (1) mean global surface temperature must be increased by -60 K (2) the mass of the atmosphere must be increased (3) liquid water must be made available and (4) the surface UV and cosmic ray flux must be substantially reduced. 

The timescale to warm Mars can be estimated from the energy required. The only practical energy source is the sunlight incident on the Martian surface. McKay et al. (1991) computed that it would take about 10 years of sunlight to warm the surface of Mars to an average temperature of +15°C, the average temperature of the Earth s... 

The centimeter radio brightness temperatures of Mars have been found to vary as a function of the central meridian longitude of the planet. Temperature differences as large as 5-10 K are observed over the full range of longitudes. The variations are believed to be due to nonconformity in the Martian surface properties however, no completely satisfactory explanation of the observations exists. 

For this analysis we select the Martian emission spectrum between 500 and 800 cm because the 667 cm CO2 band is well isolated and nearly free of lines from other constituents. The Martian spectrum has been measured by the infrared spectrometer on Mariner 9 with a spectral resolution of 2.4 cm and a good signal-to-noise ratio. Random errors are not noticeable in the large average of spectra shown in Fig. 6.1.1. The set of emission spectra displayed in Fig. 6.1.2 have been calculated with different spectral resolutions for a pure CO2 atmosphere with a surface pressure of 7 mbar and a surface temperature of 275 K. A temperature profile similar to that deduced from the measured spectrum, shown in Fig. 6.1.1, served in the radiative transfer calculations. The computed high resolution emission spectrum has been convolved with (sin27r Av/27t Av) instrument fimctions... 

Fig. 6.1.2 Calculated emission spectra assuming a CO2 atmosphere with a surface pressure of 7 mbar, a surface temperature of 275 K, and a typical Martian temperature profile. Different spectral resolutions have been used in the calculations as indicated on the right...

Several precautions can be taken to assure a good estimate of the tme surface temperature. As indicated in Eq. (8.5.1), the emissivity normally depends on the wavenumber. With a spectrometer or multichaimel radiometer one may search for a dispersion region of the surface material where the refractive index varies strongly with wavenumber (see Subsection 3.7.b). Near the index minimum the emissivity has a maximum. In addition to the composition the emissivity strongly depends on particle size and surface texture. A spectral search for an emissivity maximum is an improvement over the use of an arbitrarily chosen spectral interval. The maximum in the Martian brightness temperature near 1280 cm , shown in the upper spectrum of Fig. 6.2.8, may be an example of such a case. 

At wavenvunbers where the refractive index of the material equals that of the substance it is imbedded in (CO2 gas in the Martian case), the suspended atmospheric dust is least scattering, but still absorbing. The frequency where the index of the particles equals that of the environment is called the Christiansen frequency. If atmospheric gas and dust absorption are not excessive, the spectral region sim-rounding this frequency may provide a suitable window for a measurement of the surface temperature. 

Neugebauer, G., Miinch, G., Kieffer, H., Chase, S. C., Miner, E. (1971). Temperature and thermal properties of the Martian surface. Astronomical Journal, 76,719-28. 

A high resolution image of Mars taken from the Hubble Space Telescope is shown in Fig. 3.5. On a nice summer day, the temperature on Mars may rise up to 0°C however during a Martian night it may reach -100°C. There are channel like structures on its surface which are a hint that this planet underwent large climatic variations in the past with episodes of liquid water on its surface. Today, because of the low atmospheric pressure (only 1% of the pressure on the surface of the Earth) water cannot exist in liquid state on Mars. For liquid water on the martian surface, the atmosphere must become much denser (see also Chap. 1). Water can only sublimate on the surface of Mars i.e. it undergoes a phase transition from solid (ice) to gas (vapor) or from gas to solid. 

A cold wet Mars was described by Fairen, 2010 [123], A hypothetical martian fluid with a composition resulting from the acid weathering of basalt based on orbiter- and lander-observed surface mineralogy of Mars was included in the models. The simulations show that the hydrological cycle would have been active only in periods of dense atmosphere. A minimum atmospheric pressure is essential for water to flow, and relatively high temperatures (over 245 K) are required to trigger evaporation and snowfall minor episodes of limited liquid water on the surface could have occurred at lower temperatures (over 225 K). During times with a thin atmosphere and even lesser temperatures (under 225 K), only transient liquid water can potentially exist on most of the martian surface. 

Farquhar J, Thiemens MH (2000) The oxygen cycle of the Martian atmosphere-regoUth system secondary phases in Nakhla and Lafayette. J Geophys Res 105 11991-11998 Farquhar J, Chacko T, Ellis DJ (1996) Preservation of oxygen isotopic compositions in granuhtes from Northwestern Canada and Enderby Land, Antarctica implications for high-temperature isotopic thermometry. Contr Miner Petrol 125 213-224 Farquhar J, Thiemens MH, Jackson T (1998) Atmosphere-surface interactions on Mars mea-... 

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 eroded channels on Mars s surface show that the planet once had running water. Water boils at progressively lower temperatures as one goes to higher altitudes because the atmospheric pressure is lower. (At lower pressures it is easier for molecules to escape the surface of a liquid.) On Mars today, water would boil immediately even at the low Martian temperatures, because the atmospheric pressure is so low. This suggests that the Martian atmosphere was once much denser than it is now. Otherwise, water could never have flowed on the planet s surface. 

A very interesting subject is the application of analytical pyrolysis for the study of biomarkers in extraterrestrial samples [2], Several meteorites and lunar samples were studied using this technique. Also, Viking Lander used a Py-GC/MS system to explore the Martian atmosphere and surface [74], Commonly, a stepped pyrolysis technique has been used in these studies to determine organic components in an inorganic matrix [75], The procedure involves a set of four or five temperatures that allow the analysis of trapped gases, analysis of small volatile molecules, and the performance of true pyrolysis on macromolecules. 

Another possibility is adsorption - Xe is more likely to be adsorbed by mineral surfaces than Kr, particularly at the low temperatures that characterize Martian winters. This idea is at the heart of two more suggestions, that the elementally fractionated atmosphere was released from soil grain surfaces into the magma from which the nakhlites formed (Gilmour et al. 1999) or that adsorbed gas was implanted by shock (Gilmour et al. 2000 Bart et al. 2001). 

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