A Method for Balloon Trajectory Control

This presentation was part of the session : Short CoursesSixth International Planetary Probe WorkshopA balloon trajectory control system is discussed that is under development for use on NASA's Ultra Long Duration Balloon Project. The trajectory control system exploits the natural wind field variation with altitude to generate passive lateral control forces on a balloon using a tether-deployed aerodynamic surface below the balloon. A lifting device, such as a wing on end, is suspended on a tether well beneath the balloon to take advantage of this variation in wind velocity with altitude. The wing generates a horizontal lift force that can be directed over a wide range of angles. This force, transmitted to the balloon by a tether, alters the balloon's path providing a bias velocity of a few meters per second to the balloon drift rate. The trajectory control system enables the balloon to avoid hazards, reach targets, steer around avoidance countries and select convenient landing zones. No longer will balloons be totally at the mercy of the winds. Global Aerospace Corporation tests in April 1999 of a dynamically scaled model of the trajectory control system were carried out in ground level winds up to 15 m/s. The size of the scale model was designed to simulate the behavior of the full scale trajectory control system operating at 20 km altitude. The model confirmed many aspects of trajectory control system performance and the results will be incorporated into future development.NASA Small Business Innovation Research (SBIR) Progra

Combining Molecular Dynamics with Lattice-Boltzmann: A Hybrid Method for the Simulation of (Charged) Colloidal Systems

We present a hybrid method for the simulation of colloidal systems, that combines molecular dynamics (MD) with the Lattice-Boltzmann (LB) scheme. The LB method is used as a model for the solvent in order to take into account the hydrodynamic mass and momentum transport through the solvent. The colloidal particles are propagated via MD and they are coupled to the LB fluid by viscous forces. With respect to the LB fluid, the colloids are represented by uniformly distributed points on a sphere. Each such point (with a velocity V(r) at any off-lattice position r is interacting with the neighboring eight LB nodes by a frictional force F=\xi_0(V(r)-u(r)) with \xi_0 being a friction force and u(r) being the velocity of the fluid at the position r. Thermal fluctuations are introduced in the framework of fluctuating hydrodynamics. This coupling scheme has been proposed recently for polymer systems by Ahlrichs and D"unweg [J. Chem. Phys. 111, 8225 (1999)]. We investigate several properties of a single colloidal particle in a LB fluid, namely the effective Stokes friction and long time tails in the autocorrelation functions for the translational and rotational velocity. Moreover, a charged colloidal system is considered consisting of a macroion, counterions and coions that are coupled to a LB fluid. We study the behavior of the ions in a constant electric field. In particular, an estimate of the effective charge of the macroion is yielded from the number of counterions that move with the macroion in the direction of the electric field.Comment: 37 pages, 12 figure

Exploring Planets with Directed Aerial Robot Explorers

Global Aerospace Corporation (GAC) is developing a revolutionary system architecture for exploration of planetary atmospheres and surfaces from atmospheric altitudes. The work is supported by the NASA Institute for Advanced Concepts (NIAC). The innovative system architecture relies upon the use of Directed Aerial Robot Explorers (DAREs), which essentially are long-duration-flight autonomous balloons with trajectory control capabilities that can deploy swarms of miniature probes over multiple target areas. Balloon guidance capabilities will offer unprecedented opportunities in high-resolution, targeted observations of both atmospheric and surface phenomena. Multifunctional microprobes will be deployed from the balloons once over the target areas, and perform a multitude of functions, such as atmospheric profiling or surface exploration, relaying data back to the balloons or an orbiter. This architecture will enable low-cost, low-energy, long-term global exploration of planetary atmospheres and surfaces. This paper focuses on a conceptual analysis of the DARE architecture capabilities and science applications for Venus, Titan and Jupiter. Preliminary simulations with simplified atmospheric models show that a relatively small trajectory control wing can enable global coverage of the atmospheres of Venus and Titan by a single balloon over a 100-day mission. This presents unique opportunities for global in situ sampling of the atmospheric composition and dynamics, atmospheric profiling over multiple sites with small dropsondes and targeted deployment of surface microprobes. At Jupiter, path guidance capabilities of the DARE platforms permits targeting localized regions of interest, such as "hot spots" or the Great Red Spot. A single DARE platform at Jupiter can sample major types of the atmospheric flows (zones and belts) over a 100-day mission. Observations by deployable probes would reveal if the differences exist in radiative, dynamic and compositional environments at these sites

Gravitational instability of simply rotating AdS black holes in higher dimensions

We study the stability of AdS black hole holes rotating in a single two plane for tensor-type gravitational perturbations in $D > 6$ space-time dimensions. First, by an analytic method, we show that there exists no unstable mode when the magnitude $a$ of the angular momentum is smaller than $r_h^2/R$ where $r_h$ is the horizon radius, and $R$ is the AdS curvature radius. Then, by numerical calculations of quasinormal modes, using the separability of the relevant perturbation equations, we show that an instability occurs for rapidly rotating black holes with $a>r_h^2/R$, although the growth rate is tiny (of order $10^{-12}$ of the inverse horizon radius). We give numerical evidences indicating that this instability is caused by superradiance.Comment: 17 page

Борьба с биообрастанием природных и сточных вод с использованием энергетических воздействий

Данная работа посвящена анализу методов очистки воды для борьбы с биологическим обрастанием технологического оборудования. Рассмотрены различные способы борьбы с биологическим обрастанием, в том числе: реагентные, безреагентные и электрические. Сформирована концепция применения способа борьбы с биологическим обрастанием технологического оборудования путем электрической обработки теплоносителя. Приведена схема установки, таблица результатов и диаграмма.This work is devoted to the analysis of methods of water purification for fight against biological fouling of processing equipment. Various ways of fight against biological fouling are considered, including: reagent, reagentless and electric. The concept of application of a way of fight against biological fouling of processing equipment by electric processing of the heat carrier is created. The scheme of installation, the table of results and the chart is provided

Mechanical characteristics of the hypereutectic silumin processed by ionelectron-plasma modification

In this paper, the possibility of modifying the surface of a hypereutectic silumin (Al-(18-24) wt.%Si) is shown. Modification of the samples was carried out in two stages. At the first stage, a "film (Zr-5% Ti-5% Cu) / (Al- (18-24) wt.% Si) film system was formed by an ion-plasma method with an arc-sputtering of a Zr-5% Ti-5 cathode % Cu in the "TRIO" installation (IHCE SB RAS). In the second stage, the surface layer of the silumin of the hypereutectic composition was doped by melting the "film-substrate" system with an intense pulsed electron beam at the "SOLO" installation

Evaluation of motor transport drivers professional suitability using road traffic simulator

The article considers a method that allows to determine the degree of development of professionally important qualities of motor vehicle drivers on the basis of the developed hardware-software complex of traffic simulation. The technique of convolution of the test results on the auto-simulator and on the complex of psychological tests "Effecton" is developed. The proposed approach allows to determine the degree of correlation between the results of the developed simulation tests and existing universal psychological tests

Mars Exploration with Directed Aerial Robot Explorers

Global Aerospace Corporation (GAC) is developing a revolutionary system architecture for exploration of planetary atmospheres and surfaces from atmospheric altitudes. The work is supported by the NASA Institute for Advanced Concepts (NIAC). The innovative system architecture relies upon the use of Directed Aerial Robot Explorers (DAREs), which essentially are long‐duration‐flight autonomous balloons with trajectory control capabilities that can deploy swarms of miniature probes over multiple target areas. Balloon guidance capabilities will offer unprecedented opportunities in high‐resolution, targeted observations of both atmospheric and surface phenomena. Multifunctional microprobes will be deployed from the balloons when over the target areas, and perform a multitude of functions, such as atmospheric profiling or surface exploration, relaying data back to the balloons or an orbiter. This architecture will enable low‐cost, low‐energy, long‐term global exploration of planetary atmospheres and surfaces. A conceptual analysis of DARE capabilities and science applications for Mars is presented. Initial results of simulations indicate that a relatively small trajectory control wing can significantly change planetary balloon flight paths, especially during summer seasons in Polar Regions. This opens new possibilities for high‐resolution observations of crustal magnetic anomalies, polar layered terrain, polar clouds, dust storms at the edges of the Polar caps and of seasonal variability of volatiles in the atmosphere

The Ctf18 RFC-like complex positions yeast telomeres but does not specify their replication time

Peer reviewedPreprin