The paper describes the Rosetta Lander named Philae and introduces its complement of scientific instruments. Philae was launched aboard the European Space Agency Rosetta spacecraft on 02 March 2004 ...and is expected to land and operate on the nucleus of 67P/Churyumov-Gerasimenko at a distance of about 3 AU from the Sun. Its overall mass is ~98 kg (plus the support systems remaining on the Orbiter), including its scientific payload of ~27 kg. It will operate autonomously, using the Rosetta Orbiter as a communication relay to Earth. The scientific goals of its experiments focus on elemental, isotopic, molecular and mineralogical composition of the cometary material, the characterization of physical properties of the surface and subsurface material, the large-scale structure and the magnetic and plasma environment of the nucleus. In particular, surface and sub-surface samples will be acquired and sequentially analyzed by a suite of instruments. Measurements will be performed primarily during descent and along the first five days following touch-down. Philae is designed to also operate on a long time-scale, to monitor the evolution of the nucleus properties. Philae is a very integrated project at system, science and management levels, provided by an international consortium. The Philae experiments have the potential of providing unique scientific outcomes, complementing by in situ ground truth the Rosetta Orbiter investigations.
SD2 – How To Sample A Comet Finzi, AErcoli; Zazzera, FBernelli; Dainese, C ...
Space science reviews,
02/2007, Letnik:
128, Številka:
1-4
Journal Article
Recenzirano
SD2 (Sampler, Drill and Distribution System), is one of the instruments onboard the lander Philae of the Rosetta mission. This system is of primary importance for the lander mission since it is in ...charge to collect comet's soil samples at different depths and to distribute them to different instruments for analysis. SD2 has to meet very stringent requirements in terms of volume, mass and power consumption, operative range and severe environmental conditions. An overview of SD2 is provided, with the description of the sample acquisition and distribution procedure and an outline of the technological innovative aspects.
We used Mars Orbiter Laser Altimeter (MOLA) data from the current Mars Global Surveyor mission to characterize the topographic roughness of the Martian surface and to provide a mean to evaluate ...clutter at long (10–300 m) wavelengths. Such wavelengths are relevant for the MARSIS and SHARAD subsurface radars, which will be flown in future missions to Mars. The method of analysis is based on the assumption that topography can be described as a self‐affine fractal: 30‐km‐long segments of MOLA altimetry profiles have thus been reduced to the topographic parameters RMS height, RMS slope, and Hurst exponent, this last related to the fractal dimension, which can be used as inputs to a near‐nadir radar scattering model. The values of the Hurst exponent are greater than 0.5 for most of the surface, meaning a scaling behavior which is almost self‐similar. Maps of RMS height and Hurst exponent show that these two parameters have very different spatial distributions: whereas the RMS height is patterned after the north‐south dichotomy, the Hurst exponent follows a latitudinal trend. We make use of a multivariate method called G‐mode to classify profiles in the three‐dimensional parameter space: we find several roughness units, some of which have a strong correlation with certain geologic units, while others are bound by latitude. However, at scales between 300 m and 3 km, large stretches of the surface of Mars share common statistical properties of topography, independent from the north‐south dichotomy.
“Rosetta” is a Cornerstone Mission of the Horizon 2000 ESA Programme. Its goal is to rendezvous with a comet and to study its nucleus and coma using an orbiting spacecraft and a landed platform. The ...latter is called Philae; the Rosetta Lander has been designed to land softly on the comet nucleus and is equipped with 10 scientific instruments to perform in situ studies of cometary material.
The Lander system is provided by international consortium with the participation of Germany, France, Italy, United Kingdom, Finland, Ireland, Hungary and Austria.
The original Rosetta mission was planned to launch in January 2003 to reach comet 47P/Wirtanen in 2011 at a heliocentric distance of about 3
AU. Due to uncertainties regarding the reliability of the Ariane 5 launcher (after a catastrophic failure in December 2002) the Rosetta launch was postponed and a new mission studied.
Changed mission characteristics (e.g. in launcher capacity; no swing-by at Venus) strongly limited the number of possible alternatives. After careful investigation, a decision was taken for a mission to comet 67/P Churyumov-Gerasimenko with a launch date in February 2004 and rendezvous in 2014.
This new mission scenario has significant consequences for the Rosetta Lander, because the nucleus of P/Churyumov-Gerasimenko is expected to be considerably larger than that of P/Wirtanen. Current best estimates assume a radius of about 2.0
km and, thus, a mass which is about two orders of magnitude larger than that of the original target comet. This impacts strongly on the Lander separation, descent and landing scenario. Analysis of the increased landing risk on P/Churyumov-Gerasimenko has led to modifications of the landing gear to cope with the increased impact velocities expected.
Sorrento Lunar Declaration 2007 Foing, B.H.; Espinasse, S.; Wargo, M. ...
Advances in space research,
07/2008, Letnik:
42, Številka:
2
Journal Article
Recenzirano
We report to COSPAR the “Sorrento Lunar Declaration” from the participants to the Ninth ILEWG International Conference on the Exploration and Utilisation of the Moon (ICEUM9, Sorrento, Italy, 23–27 ...July 2006). Further information, abstracts and presentations can be found on ILEWG website
http://sci.esa.int/ilewg and the conference website
http://sci.esa.int/iceum9 Foing, B., Kosters, G., Espinasse, S., Del Vecchio Blanco, C., Sangiovanni, G., Salatti, M. (Eds.), Programme and Abstracts, Ninth ILEWG International Conference on Exploration and Utilisation of the Moon, 22–26 October 2007, Sorrento, Italy, 2007; Foing, B., Espinasse, S., Kosters, G. (Eds.), Proceedings of the Ninth ILEWG International Conference on Exploration and Utilisation of the Moon. Available online:
<http://sci.esa.int/iceum9>, ESA/ASI/ILEWG December, 2007.
Little is known about the occurrence and linkage between secreted insecticidal virulence factors in natural populations of Bacillus thuringiensis (Bt). We carried out a survey of 392 Bt strains ...isolated from various samples originating from 31 countries. The toxicity profile of the culture supernatants of these strains was determined individually against Anthonomus grandis (Coleoptera) and Spodoptera littoralis (Lepidoptera). We analyzed beta-exotoxin I production and searched for the genes encoding Vip1-2, Vip3, and Cry1I toxins in 125 of these strains. Our results showed that these insecticidal toxins were widespread in Bt but that their distribution was nonrandom, with significant linkage observed between vip3 and cry1I and between vip1-2 and beta-exotoxin I. Strains producing significant amounts of beta-exotoxin I were more frequently isolated from invertebrate samples than from dust, water, soil, or plant samples.
Italian Package for Scientific Experiments (IPSE) is a scientific autonomous micro-laboratory for Mars soil and environmental in situ analysis. It is designed to provide the capability to serve, ...handle and manage scientific miniaturised instruments accommodated inside its envelope. It provides mission management, power conditioning, thermal control, data storage and handling. Its miniaturised sample transfer chain has the capability to receive, handle and accurately position Martian soil samples under the instruments. IPSE is an example of a small and flexible laboratory, that can be integrated on different Landers and Rovers. The strict constraints of the mission make optimisation (in terms of mass, volume, power and data storage) necessary to maximise the scientific payload. Hence, adopting state-of-the-art technological solutions becomes crucial. Technological evaluation models of the most challenging subsystems have been built. Possible future developments are outlined.
A P/Wirtanen evolution model Capria, M.T.; Capaccioni, F.; Coradini, A. ...
Planetary and space science,
09/1996, Letnik:
44, Številka:
9
Journal Article
Recenzirano
Comet P/Wirtanen is the currently selected target for the international ROSETTA mission, the cornerstone ESA mission to a cometary nucleus that will be launched in 2003. Presently, little is known ...about this comet, but the successful design of the ROSETTA mission, and in particular of the on-board scientific instruments, requires some preliminary knowledge of the comet's physical parameters, such as surface temperature, percentage of active surface, intensity of gas and dust fluxes, and so on. These quantities cannot be determined through ground-based observations, so predictive models of the thermal evolution and differentiation of a cometary nucleus are needed. A thermal evolution model is applied to a comet on the orbit of P/Wirtanen with the aim of obtaining some of the needed information. The numerical code solves the heat conduction and the gas diffusion equations throughout a spherical, porous comet nucleus made of amorphous H
2O ice (the dominant constituent), CO
2 ice, CO ice and dust particles of different sizes. The equations are coupled via the source terms, which describe the sublimation and recondensation of ices as latent heat or mass exchanges. Amorphous H
2O ice can undergo an exothermal, irreversible phase transition to crystalline form. The ejection of dust is allowed only if the grains have been liberated from ice, when the drag exerted on them by the outflowing gas is stronger than the gravitational pull of the nucleus. The behaviour is simulated of a “P/Wirtanen”-like object, that starting from the Kuiper belt is injected, through multiple close encounters, in the present orbit of P/Wirtanen. This has been done with the aim of predicting the present characteristics of surface condition and emission of this poorly known comet. From the results of the simulations it can be seen that surface activity starts at 2.1 AU with gas emission and then reaches its maximum at the perihelion, where it is accompanied by a strong dust emission; the range of the computed comet surface temperatures is, at the equator and at the perihelion, between 130 and 200 K. Differences between day and night temperatures on the surface of the nucleus can reach 50 K at perihelion, with a consequent variation in the H
2O and dust emission rate, but the flux of more volatile ice, like CO
2 and CO, is not affected. Such ices can be found at depths varying from a few metres for CO
2 to hundreds of metres for CO.
The Italian drill “DEEDRI” is going to be the lander based sample acquisition system for the Mars Surveyor Program of the Mars Sample Return mission. DEEDRI is capable to collect core/sand sample of ...the martian soil down to 50 cm in depth. The MA_MISS experiment belongs to the DEEDRI system and it will be dedicated to observe the wall of the excavated hole in terms of infrared spectral reflectance in the range 0.8–2.8 μm. The spectral sampling is about 20 nm while the spatial sampling is 100 μm over the target. The optical window of MA_MISS is placed very close to the drill tip so that the target view to be observed can span from the soil down to 50 cm. The proximity optics and electronics of MA_MISS have to be very miniaturized since they will be collocated inside the drill tool in a very limited volume of about 25 mm in diameter. On the other side the main electronics will be on the lander and it will communicate through an interface based on slip rings devices. MA_MISS can acquire in different observation modes. The images are scanned by moving the DEEDRI itself. One image ring is built up by acquiring contiguous images of the MA_MISS slit. The study of the Martian subsurface will provide important constraints on the nature, timing and duration of alteration and sedimentation processes on Mars, as well as on the complex interactions between the surface and the atmosphere. This study will permit to infer the history of erosion, transport and deposition of loose material. Alteration processes can dominate the mineralogy of the Martian surface: it will be essential to study the mineralogy of deeper layers, where a more limited alteration took place. MA_MISS can provide very important scientific return from the subsurface of Mars along with a selection criteria for the samples collection.
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