Refinements in the data analysis of VIRTIS-M-IR Venus nightside spectra

The successful long-duration radiation measurements performed by the VIRTIS instrument aboard ESA’s Venus Express spacecraft have provided an excellent collection of atmospheric and surface data that stand out due to their high temporal and spatial coverage of the planet and due to a high diversity of measurement and environmental conditions.     

The MELISSA pilot plant facility as as integration test-bed for advanced life support systems.

The different advances in the Micro Ecological Life Support System Alternative project (MELISSA), fostered and coordinated by the European Space Agency, as well as in other associated technologies, are integrated and demonstrated in the MELISSA Pilot Plant laboratory. During the first period of operation, the definition of the different compartments at an individual basis has been achieved, and the complete facility is being re-designed to face a new period of integration of all these compartments. The final objective is to demonstrate the potentiality of biological systems such as MELISSA as life support systems. The facility will also serve as a test bed to study the robustness and stability of the continuous operation of a complex biological system. This includes testing of the associated instrumentation and control for a safe operation, characterization of the chemical and microbial safety of the system, as well as tracking the genetic stability of the microbial strains used. The new period is envisaged as a contribution to the further development of more complete biological life support systems for long-term manned missions, that should be better defined from the knowledge to be gained from this integration phase. This contribution summarizes the current status of the Pilot Plant and the planned steps for the new period.     

New asymmetry monitoring techniques: Effects on attitude control

The asymmetry limitation between left and right wing flap surfaces is one of the most severe requirements for the design of the actuation and control system. Each asymmetry exceeding a defined value must be detected and limited by appropriate monitoring devices equipped with a suitable software.In the design of a new flap control system the development of the asymmetry monitoring system plays a very important role and it is a very debated matter in industrial field. Nevertheless in scientific literature this topic is so neglected that, at the best of our knowledge, no paper dealing with the specific argument exists, except for the authors' works listed in the references.The currently used monitoring technique is based on the differential position control between left and right surfaces. Nevertheless in particularly severe conditions the above mentioned technique may be unable to prevent potentially critical asymmetries; in order to limit the above mentioned shortcomings, the authors proposed and developed some innovative monitoring techniques in previous papers. Their use generally reduces the asymmetry slightly, but in some cases it may have an unreliable behavior. In order to overcome the shortcomings of the previous models, in this work the authors develop and propose new different monitoring strategies and assess their positive effects on the maximum asymmetry following a torque tube failure.     

A Thermodynamic Approach to the Magnetospheric Complexity: The Role of Fluctuations

Recent studies evidenced that the magnetotail dynamics looks like the one of an avalanching system. This fact has been related with a near criticality dynamics and modelled by singular diffusion and transport equations. Here, we discuss some features of the Earth’s magnetotail dynamics using a thermodynamic approach. In detail we discuss the role played by fluctuations in singular diffusion and relaxation processes from a non-equilibrium thermodynamics point of view. Moreover, the emergence of non-Gaussian statistics is discussed in the framework of the thermodynamics of composite systems.     

Complexity,Forced and/or Self-Organized Criticality,and Topological Phase Transitions in Space Plasmas

The first definitive observation that provided convincing evidence indicating certain turbulent space plasma processes are in states of ‘complexity’ was the discovery of the apparent power-law probability distribution of solar flare intensities. Recent statistical studies of complexity in space plasmas came from the AE index, UVI auroral imagery, and in-situ measurements related to the dynamics of the plasma sheet in the Earth's magnetotail and the auroral zone. In this review, we describe a theory of dynamical ‘complexity’ for space plasma systems far from equilibrium. We demonstrate that the sporadic and localized interactions of magnetic coherent structures are the origin of ‘complexity’ in space plasmas. Such interactions generate the anomalous diffusion, transport, acceleration, and evolution of the macroscopic states of the overall dynamical systems. Several illustrative examples are considered. These include: the dynamical multi- and cross-scale interactions of the macro-and kinetic coherent structures in a sheared magnetic field geometry, the preferential acceleration of the bursty bulk flows in the plasma sheet, and the onset of ‘fluctuation induced nonlinear instabilities’ that can lead to magnetic reconfigurations. The technique of dynamical renormalization group is introduced and applied to the study of two-dimensional intermittent MHD fluctuations and an analogous modified forest-fire model exhibiting forced and/or self-organized criticality [FSOC] and other types of topological phase transitions. This revised version was published online in August 2006 with corrections to the Cover Date.     

Microphysics of Magnetic Reconnection

Magnetic reconnection is a universal phenomenon where energy is efficiently converted from the magnetic field to charged particles as a result of global magnetic topology changes during which earlier separated plasma regions become magnetically connected. While the reconnection affects large volumes in space most of the topology changes and of the energization occur within small localized regions. Regions of special importance are the X-region and the separatrix region. The understanding of the microphysics of these regions is crucial for the overall understanding of the reconnection. The Earth magnetosphere is the best environment where the details of these regions can be studied in situ. We summarize their main properties and discuss recent spacecraft observations.     

Active stars and systems

The most notable manifestations of stellar activity are reviewed with particular emphasis on the merging picture of solar-type activity in physical conditions different from those in the Sun. Evidence for starspots, plages and high-level coronal emissions is presented from observations covering a wide range of spectral bands: from X-ray to radio wavelengths. The main physical parameters of the active areas in the active stars, when compared with solar values, indicate that the basic requirement for activity phenomena to develop is the presence of observationally elusive localized magnetic fields on and above the stellar surface. The importance of coordinated programs involving simultaneous observations from the ground and from space - aiming at empirical and theoretical modeling of activity phenomena - is stressed.     

Physical characterization of the deep-space debris WT1190F: A testbed for advanced SSA techniques

We report on extensive ${\mathit{BVR}}_c{I}_c$ photometry and low-resolution ($\lambda /\mathrm{\Delta }\lambda ～250$) spectroscopy of the deep-space debris WT1190F, which impacted Earth offshore from Sri Lanka, on 2015 November 13. In spite of its likely artificial origin (as a relic of some past lunar mission), the case offered important points of discussion for its suggestive connection with the envisaged scenario for a (potentially far more dangerous) natural impactor, like an asteroid or a comet.Our observations indicate for WT1190F an absolute magnitude $R_c={32.45}_{\pm 0.31}$, with a flat dependence of reflectance on the phase angle, such as ${\mathit{dR}}_c/d?～{0.007}_{\pm 2}$?mag?deg^?1. The detected short-timescale variability suggests that the body was likely spinning with a period twice the nominal figure of $P_{\mathrm{flash}}={1.4547}_{\pm 0.0005}\mathrm{s}$, as from the observed lightcurve. In the ${\mathit{BVR}}_c{I}_c$ color domain, WT1190F closely resembled the Planck deep-space probe. This match, together with a depressed reflectance around 4000 and 8500 Å may be suggestive of a “grey” (aluminized) surface texture.The spinning pattern remained in place also along the object fiery entry in the atmosphere, a feature that may have partly shielded the body along its fireball phase perhaps leading a large fraction of its mass to survive intact, now lying underwater along a tight ($～1\times 80$?km) strip of sea, at a depth of 1500?m or less.Under the assumption of Lambertian scatter, an inferred size of ${216}_{\pm 30}/\sqrt{\alpha /0.1}$?cm is obtained for WT1190F. By accounting for non-gravitational dynamical perturbations, the Area-to-Mass ratio of the body was in the range $(0.006?\mathit{AMR}?0.011)$?m²?kg^?1.Both these figures resulted compatible with the two prevailing candidates to WT1190F’s identity, namely the Athena II Trans-Lunar Injection Stage of the Lunar Prospector mission, and the ascent stage of the Apollo 10 lunar module, callsign “Snoopy”. Both candidates have been analyzed in some detail here through accurate 3D CAD design mockup modelling and BRDF reflectance rendering to derive the inherent photometric properties to be compared with the observations.     

Impact of Distance Determinations on Galactic Structure. I. Young and Intermediate-Age Tracers

Here we discuss impacts of distance determinations on the Galactic disk traced by relatively young objects. The Galactic disk, \(\sim40~\mbox{kpc}\) in diameter, is a cross-road of studies on the methods of measuring distances, interstellar extinction, evolution of galaxies, and other subjects of interest in astronomy. A proper treatment of interstellar extinction is, for example, crucial for estimating distances to stars in the disk outside the small range of the solar neighborhood. We’ll review the current status of relevant studies and discuss some new approaches to the extinction law. When the extinction law is reasonably constrained, distance indicators found in today and future surveys are telling us stellar distribution and more throughout the Galactic disk. Among several useful distance indicators, the focus of this review is Cepheids and open clusters (especially contact binaries in clusters). These tracers are particularly useful for addressing the metallicity gradient of the Galactic disk, an important feature for which comparison between observations and theoretical models can reveal the evolution of the disk.     

Aerodynamic database development of the ESA intermediate experimental vehicle

This work deals with the aerodynamic database development of the Intermediate Experiment Vehicle.