270 research outputs found
Unsupervised classification of Mercury's visible-near-infrared reflectance spectra: comparison with major element compositions
The Science Case for a Return to Enceladus
The plume of Enceladus is unique in the solar system in providing direct access to fresh material from an
extraterrestrial subsurface ocean. The Cassini Mission, though not specifically designed for it, was able to take
advantage of the plume to conduct the best characterization to date of an extraterrestrial ocean. Evidence gathered
from multiple instruments points to a global, subsurface liquid water ocean rich in salts and organic compounds,
with water-rock interactions occurring presumably in hydrothermal systems at or below the moonâs sea floor.
Meeting the criteria of âextended regions of liquid water, conditions favorable for the assembly of complex organic
molecules, and energy source(s) to sustain metabolism,â the ocean of Enceladus can therefore be considered
habitable. It is also the only confirmed place beyond the Earth where we can easily sample fresh material from a
demonstrably habitable environment without the complications of digging or drilling. The next step is to
investigate whether Enceladusâ ocean is actually inhabited. Here, we summarize the evidence for Enceladusâ ocean
and its habitability, identify constraints and outstanding questions on the detectability of life within its ocean, and
recommend a return to Enceladus with a dedicated search-for-life mission (or missions)
Modular Medical Imaging Agents Based on Azide-Alkyne Huisgen Cycloadditions:Synthesis and Pre-Clinical Evaluation of(18)F-Labeled PSMA-Tracers for Prostate Cancer Imaging
Since the seminal contribution of Rolf Huisgen to develop the [3+2] cycloaddition of 1,3-dipolar compounds, its azideâalkyne variant has established itself as the key step in numerous organic syntheses and bioorthogonal processes in materials science and chemical biology. In the present study, the copper(I)-catalyzed azideâalkyne cycloaddition was applied for the development of a modular molecular platform for medical imaging of the prostate-specific membrane antigen (PSMA), using positron emission tomography. This process is shown from molecular design, through synthesis automation and in vitro studies, all the way to pre-clinical in vivo evaluation of fluorine-18- labeled PSMA-targeting âF-PSMA-MICâ radiotracers (t1/2=109.7 min). Pre-clinical data indicate that the modular PSMA-scaffold has similar binding affinity and imaging properties to the clinically used [68Ga]PSMA-11. Furthermore, we demonstrated that targeting the arene-binding in PSMA, facilitated through the [3+2]cycloaddition, can improve binding affinity, which was rationalized by molecular modeling. The here presented PSMA-binding scaffold potentially facilitates easy coupling to other medical imaging moieties, enabling future developments of new modular imaging agents
Lunar Exploration Orbiter (LEO): Providing a Globally Covered, Highly Resolved, Integrated Geological, Geochemical and Gephysical Data Base of the Moon
The German initiative for the Lunar Exploration Orbiter (LEO) originated from the
national conference âExploration of our Solar Systemâ, held in Dresden in November 2006. Major result of this conference was that the Moon is of high interest for the scientific community for various reasons, it is affordable to perform an orbiting mission to Moon and it insures technological and scientific progress necessary to assist further exploration activities of our Solar System. Based on scientific proposals elaborated by 50 German scientists in January 2007, a preliminary payload of 12 instruments was defined. Further analysis were initated by DLR in the frame of two industry contracts, to perform a phase-zero mission definition.
The Moon, our next neighbour in the Solar System is the first choice to learn, how to work and live without the chance of immediate support from earth and to get prepared for further and farther exploration missions. We have to improve our
scientific knowledge base with respect to the Moon applying modern and state of the art research tools and methods. LEO is planed to be launched in 2012 and shall orbit the Moon for about four years in a low altitude orbit
Mercury's Weather-Beaten Surface: Understanding Mercury in the Context of Lunar and Asteroid Space Weathering Studies
Understanding the composition of Mercury's crust is key to comprehending the formation of the planet. The regolith, derived from the crustal bedrock, has been altered via a set of space weathering processes. These processes are the same set of mechanisms that work to form Mercury's exosphere, and are moderated by the local space environment and the presence of an intrinsic planetary magnetic field. The alterations need to be understood in order to determine the initial crustal compositions. The complex interrelationships between Mercury's exospheric processes, the space environment, and surface composition are examined and reviewed. The processes are examined in the context of our understanding of these same processes on the lunar and asteroid regoliths. Keywords: Mercury (planet) Space weathering Surface processes Exosphere Surface composition Space environment
THERMAP: a mid-infrared spectro-imager for space missions to small bodies in the inner solar system
We present THERMAP, a mid-infrared (8-16 ÎŒm) spectro-imager for space missions to small bodies in the inner solar system, developed in the framework of the MarcoPolo-R asteroid sample return mission. THERMAP is very well suited to characterize the surface thermal environment of a NEO and to map its surface composition. The instrument has two channels, one for imaging and one for spectroscopy: it is both a thermal camera with full 2D imaging capabilities and a slit spectrometer. THERMAP takes advantage of the recent technological developments of uncooled microbolometers detectors, sensitive in the mid-infrared spectral range. THERMAP can acquire thermal images (8-18 ÎŒm) of the surface and perform absolute temperature measurements with a precision better than 3.5 K above 200 K. THERMAP can acquire mid-infrared spectra (8-16 ÎŒm) of the surface with a spectral resolution Îλ of 0.3 ÎŒm. For surface temperatures above 350 K, spectra have a signal-to-noise ratio >60 in the spectral range 9-13 ÎŒm where most emission features occur
OSS (Outer Solar System): A fundamental and planetary physics mission to Neptune, Triton and the Kuiper Belt
The present OSS mission continues a long and bright tradition by associating
the communities of fundamental physics and planetary sciences in a single
mission with ambitious goals in both domains. OSS is an M-class mission to
explore the Neptune system almost half a century after flyby of the Voyager 2
spacecraft. Several discoveries were made by Voyager 2, including the Great
Dark Spot (which has now disappeared) and Triton's geysers. Voyager 2 revealed
the dynamics of Neptune's atmosphere and found four rings and evidence of ring
arcs above Neptune. Benefiting from a greatly improved instrumentation, it will
result in a striking advance in the study of the farthest planet of the Solar
System. Furthermore, OSS will provide a unique opportunity to visit a selected
Kuiper Belt object subsequent to the passage of the Neptunian system. It will
consolidate the hypothesis of the origin of Triton as a KBO captured by
Neptune, and improve our knowledge on the formation of the Solar system. The
probe will embark instruments allowing precise tracking of the probe during
cruise. It allows to perform the best controlled experiment for testing, in
deep space, the General Relativity, on which is based all the models of Solar
system formation. OSS is proposed as an international cooperation between ESA
and NASA, giving the capability for ESA to launch an M-class mission towards
the farthest planet of the Solar system, and to a Kuiper Belt object. The
proposed mission profile would allow to deliver a 500 kg class spacecraft. The
design of the probe is mainly constrained by the deep space gravity test in
order to minimise the perturbation of the accelerometer measurement.Comment: 43 pages, 10 figures, Accepted to Experimental Astronomy, Special
Issue Cosmic Vision. Revision according to reviewers comment
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