Marco Polo: A Sample Return Mission to a Primitive Near-Earth Object in Assessment Study in the ESA Program Cosmic Vision 2015-2025

Meteoritics and Planetary Science Supplement, 72, p. 5261 (2009)International audienc

Monitoramento da contaminação por elementos traço em ostras comercializadas em Recife, Pernambuco, Brasil Monitoring of trace elements in oysters marketed in Recife, Pernambuco, Brazil

Amostras de ostras comercializadas em Recife, Pernambuco, Brasil, foram monitoradas em relação ao conteúdo de elementos traço (Hg, Zn, Fe, Cu e Mn) durante o período de um ano (março/2001 a fevereiro/2002). Mercúrio foi o principal contaminante encontrado nas ostras e o elemento que apresenta maior risco à saúde pública. Foram encontrados valores de concentração de Hg em ostras de até 551,12µg/kg (peso úmido). Esses valores sugerem que a ingestão de ostras deve ser feita com restrições, principalmente, pela população que vive de sua coleta como forma de subsistência, por crianças, e mulheres grávidas. A avaliação dos níveis de mercúrio em frutos do mar é um importante fator para avaliar o risco de contaminação por mercúrio em pessoas não ocupacionalmente expostas.<br>Samples of oysters marketed in Recife, Pernambuco, Brazil, were monitored for the concentration of trace elements (Hg, Zn, Fe, Cu, and Mn) for one year (from March 2001 to February 2002). Mercury was the principal contaminant found in oysters and the element posing the greatest public health risk. Mercury levels in oysters reached 551.12µg/kg (wet weight). These values suggest that oyster consumption should be restricted, especially among communities that gather them as a subsistence activity, as well as by children and pregnant women. Evaluation of mercury concentration in seafood is an important factor for assessing the risk of contamination among individuals who are not occupationally exposed

MARCO POLO: near earth object sample return mission

MARCO POLO is a joint European--Japanese sample return mission to a Near-Earth Object. This Euro-Asian mission will go to a primitive Near-Earth Object (NEO), which we anticipate will contain primitive materials without any known meteorite analogue, scientifically characterize it at multiple scales, and bring samples back to Earth for detailed scientific investigation. Small bodies, as primitive leftover building blocks of the Solar System formation process, offer important clues to the chemical mixture from which the planets formed some 4.6 billion years ago. Current exobiological scenarios for the origin of Life invoke an exogenous delivery of organic matter to the early Earth: it has been proposed that primitive bodies could have brought these complex organic molecules capable of triggering the pre-biotic synthesis of biochemical compounds. Moreover, collisions of NEOs with the Earth pose a finite hazard to life. For all these reasons, the exploration of such objects is particularly interesting and urgent. The scientific objectives of MARCO POLO will therefore contribute to a better understanding of the origin and evolution of the Solar System, the Earth, and possibly Life itself. Moreover, MARCO POLO provides important information on the volatile-rich (e.g. water) nature of primitive NEOs, which may be particularly important for future space resource utilization as well as providing critical information for the security of Earth. MARCO POLO is a proposal offering several options, leading to great flexibility in the actual implementation. The baseline mission scenario is based on a launch with a Soyuz-type launcher and consists of a Mother Spacecraft (MSC) carrying a possible Lander named SIFNOS, small hoppers, sampling devices, a re-entry capsule and scientific payloads. The MSC leaves Earth orbit, cruises toward the target with ion engines, rendezvous with the target, conducts a global characterization of the target to select a sampling site, and delivers small hoppers (MINERVA type, JAXA) and SIFNOS. The latter, if added, will perform a soft landing, anchor to the target surface, and make various in situ measurements of surface/subsurface materials near the sampling site. Two surface samples will be collected by the MSC using ``touch and go'' manoeuvres. Two complementary sample collection devices will be used in this phase: one developed by ESA and another provided by JAXA, mounted on a retractable extension arm. After the completion of the sampling and ascent of the MSC, the arm will be retracted to transfer the sample containers into the MSC. The MSC will then make its journey back to Earth and release the re-entry capsule into the Earth's atmosphere

Thermostimulable Wax@SiO2 Core-Shell Particles

We propose a new synthesis pathway without any sacrificial template to prepare original monodisperse thermo-7 responsive capsules made of a wax core surrounded by a silica shell. Under heating, the inner wax expands and the shell 8 breaks, leading to the liquid oil release. Such capsules that allow triggered deliverance provoked by an external stimulus 9 belong to the class of smart materials. The process is based on the elaboration of size-controlled emulsions stabilized by 10 particles (Pickering emulsions) exploiting the limited coalescence phenomenon. Then the emulsions are cooled down 11 and the obtained suspensions are mineralized by the hydrolysis and condensation of a monomer at the wax-water 12 interface, leading to the formation of capsules. The shell break and the liquid oil release are provoked by heating above 13 the wax melting temperature. We characterize the obtained materials and examine the effect of processing parameters 14 and heating history. By an appropriate choice of the wax, the temperature of release can easily be tuned