IRSUTE, a small satellite for water budget estimate with high resolution infrared imagery

The estimation of land surface fluxes has been recognized in the last ten years as a major scientific issue for the improvement of our knowledge on heat and water budgets and therefore of models in meteorology, hydrology, agriculture and environment. Remote sensing is an adequate mean for filling the gap which exists between small scale instruments or modeling (10m) and the regional or global scales where they have to be determined with a typical grid element of the order of 1 to 10 km. IRSUTE (for Infra Red miniSatellite Unit for Terrestrial Environment) is a scientific small satellite mission providing thermal imagery for the determination and analysis of soil/vegetation/atmosphere processes at the field scale and therefore for providing the necessary data for a scaling-up of these processes from local to regional scales. The main specifications, will allow this instrument to optimize the correction of the sensed radiance and to retrieve the fluxes with an accuracy of the order of 50w/m² (or 0.8mm/day). IRSUTE is designed to have high spatial resolution (50m), across and along track viewing capabilities, 5 channels : visible/NIR, 3.7 μ, and 3 TIR in the 8–11 μm band with a good radiometric sensitivity (NEΔT = 0.1 K). The instrument is to be implemented onboard a small satellite (typically a PROTEUS platform) placed on a sun-synchronous orbit allowing high repetitivity (1 to 3 days). It is based on the push-broom technique which uses IR-CCD linear array detectors positioned in the cryocooled focal plane of a large bandwidth collecting optics.     

Geometric calibration of Colour and Stereo Surface Imaging System of ESA’s Trace Gas Orbiter

There are many geometric calibration methods for “standard” cameras. These methods, however, cannot be used for the calibration of telescopes with large focal lengths and complex off-axis optics. Moreover, specialized calibration methods for the telescopes are scarce in literature. We describe the calibration method that we developed for the Colour and Stereo Surface Imaging System (CaSSIS) telescope, on board of the ExoMars Trace Gas Orbiter (TGO). Although our method is described in the context of CaSSIS, with camera-specific experiments, it is general and can be applied to other telescopes. We further encourage re-use of the proposed method by making our calibration code and data available on-line.     

Searching for life on Mars: selection of molecular targets for ESA's aurora ExoMars mission

The European Space Agency's ExoMars mission will seek evidence of organic compounds of biological and non-biological origin at the martian surface. One of the instruments in the Pasteur payload may be a Life Marker Chip that utilizes an immunoassay approach to detect specific organic molecules or classes of molecules. Therefore, it is necessary to define and prioritize specific molecular targets for antibody development. Target compounds have been selected to represent meteoritic input, fossil organic matter, extant (living, recently dead) organic matter, and contamination. Once organic molecules are detected on Mars, further information is likely to derive from the detailed distribution of compounds rather than from single molecular identification. This will include concentration gradients beneath the surface and gradients from generic to specific compounds. The choice of biomarkers is informed by terrestrial biology but is wide ranging, and nonterrestrial biology may be evident from unexpected molecular distributions. One of the most important requirements is to sample where irradiation and oxidation are minimized, either by drilling or by using naturally excavated exposures. Analyzing regolith samples will allow for the search of both extant and fossil biomarkers, but sequential extraction would be required to optimize the analysis of each of these in turn.     

Geochemical Consequences of Widespread Clay Mineral Formation in Mars’ Ancient Crust

Clays form on Earth by near-surface weathering, precipitation in water bodies within basins, hydrothermal alteration (volcanic- or impact-induced), diagenesis, metamorphism, and magmatic precipitation. Diverse clay minerals have been detected from orbital investigation of terrains on Mars and are globally distributed, indicating geographically widespread aqueous alteration. Clay assemblages within deep stratigraphic units in the Martian crust include Fe/Mg smectites, chlorites and higher temperature hydrated silicates. Sedimentary clay mineral assemblages include Fe/Mg smectites, kaolinite, and sulfate, carbonate, and chloride salts. Stratigraphic sequences with multiple clay-bearing units have an upper unit with Al-clays and a lower unit with Fe/Mg-clays. The typical restriction of clay minerals to the oldest, Noachian terrains indicates a distinctive set of processes involving water-rock interaction that was prevalent early in Mars history and may have profoundly influenced the evolution of Martian geochemical systems. Current analyses of orbital data have led to the proposition of multiple clay-formation mechanisms, varying in space and time in their relative importance. These include near-surface weathering, formation in ice-dominated near-surface groundwaters, and formation by subsurface hydrothermal fluids. Near-surface, open system formation of clays would lead to fractionation of Mars’ crustal reservoir into an altered crustal reservoir and a sedimentary reservoir, potentially involving changes in the composition of Mars’ atmosphere. In contrast, formation of clays in the subsurface by either aqueous alteration or magmatic cooling would result in comparatively little geochemical fractionation or interaction of Mars’ atmospheric, crustal, and magmatic reservoirs, with the exception of long-term sequestration of water. Formation of clays within ice would have geochemical consequences intermediate between these endmembers. We outline the future analyses of orbital data, in situ measurements acquired within clay-bearing terrains, and analyses of Mars samples that are needed to more fully elucidate the mechanisms of martian clay formation and to determine the consequences for the geochemical evolution of the planet.     

法国MBDA爆震和连续爆震波发动机的研发(英文)

连续爆震波发动机(CDWE)可以弱化一般爆震发动机(PDE)对环境条件的要求,尤其是初始条件要求弱化简化了发动机结构。为了探讨CDWE用于空间发射器的可行性,MBDA与Lavrentiev学院联合进行了一些试验,研究了其工作模式和一些关键点。结果发现:这种发动机在非常小的装置中可提供可观的推力(275daN,条件:直径50mm,长100mm,航空煤油加氧气)。如果采用扩张型喷管,推力还可能增加。在现有尺寸下,插入式或气动锥喷管似乎是最佳设计,在同一流量下,发动机的矢量能力是解决姿态控制的一个方法。热流量非常大,但主要集中在喷射壁面,这一点将有助于在燃烧室内气化喷入的液体燃料。另外,做了初步试验来评估C/SiC复合材料在转动爆震波非常恶劣的机械环境下的性能。在这些研究以外,MBDA还设计了大尺寸地面实验装置来研究使用LH2/LOx混合物的连续爆震波发动机的所有相关问题。作为大尺寸研发的第一步,小尺寸的演示在2010年春季进行。     

法国高超声速冲压发动机技术研究(英文)

法国正在致力于发展高超声速吸气式推进系统和推阻平衡预测能力所需要的技术。通过地面试验研究完成其大部分技术开发,目前正在对燃烧室进行攻关研究,以确保燃烧效率和结构热力强度满足要求。另一方面,为了掌握推阻平衡技术,必须进行飞行试验。因此,MBDA和ONERA正在推进LEA飞行试验计划。此计划始于2003年1月,准备在后续几年内完成马赫数4到8的若干次飞行试验。在2009年中期,通过关键设计评估完成了LEA飞行器推进系统的验证。将确定在2011年春季通过一系列自由射流试验验证飞行器的推阻平衡。此外,系统地开展了可重复使用运载器和高速民用飞行器的可行性和可实现的工作性能研究。     

Advanced biostack: experiment 1 ES 027 on Spacelab-1.

The radiobiological properties of the heavy ions of cosmic radiation were investigated on Spacelab 1 by use of biostacks, monolayers of biological test organisms sandwiched between thin foils of different types of nuclear track detectors. Biostacks were exposed to cosmic radiation at several locations with different shielding environments in the module and on the pallet. Evaluations of the physical and biological components of the experiment to date indicate that in general they survived the spaceflight in good condition. Dosimetric data are presented for the different shielding environments.     

The IRIDIUMR main mission antenna concept

The design of a novel phased array panel that provides the L-band satellite to ground links for the IRIDIUM global communications system is presented. Key components and aspects of this phased array antenna are discussed, including the beamforming architecture, radiated intermodulation products, the patch radiators, and the T/R module. The strategy for minimizing DC power consumption over a large range of multicarrier rf output power is described. Finally, test results showing compliant array operation are summarized     

The PROCESS experiment: amino and carboxylic acids under Mars-like surface UV radiation conditions in low-earth orbit

The search for organic molecules at the surface of Mars is a top priority of the next Mars exploration space missions: Mars Science Laboratory (NASA) and ExoMars (ESA). The detection of organic matter could provide information about the presence of a prebiotic chemistry or even biological activity on this planet. Therefore, a key step in interpretation of future data collected by these missions is to understand the preservation of organic matter in the martian environment. Several laboratory experiments have been devoted to quantifying and qualifying the evolution of organic molecules under simulated environmental conditions of Mars. However, these laboratory simulations are limited, and one major constraint is the reproduction of the UV spectrum that reaches the surface of Mars. As part of the PROCESS experiment of the European EXPOSE-E mission on board the International Space Station, a study was performed on the photodegradation of organics under filtered extraterrestrial solar electromagnetic radiation that mimics Mars-like surface UV radiation conditions. Glycine, serine, phthalic acid, phthalic acid in the presence of a mineral phase, and mellitic acid were exposed to these conditions for 1.5 years, and their evolution was determined by Fourier transform infrared spectroscopy after their retrieval. The results were compared with data from laboratory experiments. A 1.5-year exposure to Mars-like surface UV radiation conditions in space resulted in complete degradation of the organic compounds. Half-lives between 50 and 150?h for martian surface conditions were calculated from both laboratory and low-Earth orbit experiments. The results highlight that none of those organics are stable under low-Earth orbit solar UV radiation conditions.