Antideuteron based dark matter search with GAPS: Current progress and future prospects

The General Antiparticle Spectrometer (GAPS) is a new approach to the indirect detection of dark matter. It relies on searching for primary antideuterons produced in the annihilation of dark matter in the galactic halo. Low energy antideuterons produced through Standard Model processes, such as collisions of cosmic-rays with interstellar baryons, are greatly suppressed compared to primary antideuterons. Thus a low energy antideuteron search provides a clean signature of dark matter. In GAPS antiparticles are slowed down and captured in target atoms. The resultant exotic atom deexcites with the emission of X-rays and annihilation pions, protons and other particles. A tracking geometry allows for the detection of the X-rays and particles, providing a unique signature to identify the mass of the antiparticle. A prototype detector was successfully tested at the KEK accelerator in 2005, and a prototype GAPS balloon flight is scheduled for 2011. This will be followed by a full scale experiment on a long duration balloon from Antarctica in 2014. We discuss the status and future plans for GAPS.     

A Parallel Adaptive 3D MHD Scheme for Modeling Coronal and Solar Wind Plasma Flows

A parallel adaptive mesh refinement (AMR) scheme is described for solving the governing equations of ideal magnetohydrodynamics (MHD) in three space dimensions. This solution algorithm makes use of modern finite-volume numerical methodology to provide a combination of high solution accuracy and computational robustness. Efficient and scalable implementations of the method have been developed for massively parallel computer architectures and high performance achieved. Numerical results are discussed for a simplified model of the initiation and evolution of coronal mass ejections (CMEs) in the inner heliosphere. The results demonstrate the potential of this numerical tool for enhancing our understanding of coronal and solar wind plasma processes. This revised version was published online in June 2006 with corrections to the Cover Date.     

Design and analysis of a regulated peak-power tracking system

A regulated peak-power tracking (RPPT) system for space power application is proposed. Large-signal stability analysis is provided to understand the main four different modes of operations of the system, as well as the mode transitions. A simple and effective control scheme for the system is also proposed. Small-signal analysis is performed thereafter to provide design optimization, and the predictions are verified by computer simulations     

Microperturbations on the <Emphasis Type="Italic">International Space Station</Emphasis> during physical exercises of the crew

The results of a preliminary analysis of microperturbations on the International Space Station during physical exercises of the crew are presented. The goal of this paper is to identify the parameters of perturbations when physical exercises are performed. The results of measurements by sensors of microaccelerations of both Russian and American segments during physical exercises in the service module of the Russian segment are analyzed.     

A method to ensure energy security of satellite communication systems

A method is substantiated to ensure energy security for the satellite communication systems (SCS) at a close position of the radio interception receiver. This is done by lowering the carrier frequency down to f ₀ = 60…80 MHz and by applying spaced measurements with n ≥ 4 receiving antennas.     

Stellar coronagraph using the principle of achromatic null-interferometer

In order to observe exoplanets we propose a space-based achromatic stellar coronagraph combined with a 0.8–1.5 m telescope. We develop an achromatic common path interferometer for observing an exoplanet (a faint off-axis source) on the background of a hoste star (bright axial source). An image of the star and its copy acquire an achromatic phase shift by 180° and interfere in antiphase. The achromatic phase shift is caused by geometric phase in the scheme of a three-dimensional interferometer. The interference process divides spatially the dark and light fields of the star image redirecting them to the opposite sides of a beam splitter. The interference process does not weaken the image of a planet, with equal intensities it is redirected to both sides of a beam splitter. The suggested scheme of common path interferometer ensures mechanical stability. The background signal is experimentally demonstrated to be reduced by six orders of magnitude.     

Solution to the problem of stability of regular precessions of a symmetrical gyrostat in Newtonian field

The constraints imposed on parameters of a force field and of a symmetrical gyrostat in it are determined, at which regular precession of this gyrostat demonstrate Lyapunov stability (or, respectively, instability).     

未来的飞机推进

TheFutureofAircraftPropulsion编者按PhilRuffle（罗富）先生现任罗·罗公司工程技术董事，负责公司所有的技术工作。自1961年加入公司开始就从练习生做起，以后曾担任和主持了一系列工作，在发动机制造领域具有丰富的经验。目前，他是英国皇家工程院、皇家宇航学会以及机械工程师研究院院士。最近，他又被北京航空航天大学授予名誉教授。本文是罗富先生在3月23日举行的“罗·罗／宝马一罗·罗／中航总技术研讨会上作的一篇报告。此文以罗·罗公司生产的发动机为例，对目前民用发动机技术进行了详细的分析，并对该技术今后的发展趋势作…     

Tracking of DABS-Equipped Aircraft

The Discrete Address Beacon System (DABS) is scheduled to replace the Air Traffic Control Beacon System (ATCRBS) as the prime sensing tool for air traffic control in the 1980's. The design of DABS requires knowledge of the tracking accuracy obtainable as a function of various system parameters. In particular, the potential value of air-to-ground telemetry of turn-rate data and its effect on intermittent positive control (IPC) must be assessed. The design of DABS tracking algorithms is discussed, and the results obtained with a Kalman tracker simulation are given. The major finding is that turn-rate telemetry of moderate accuracy can improve tracking by a factor of 6 to 10.     

Consequences of collisions of natural cosmic bodies with the Earth’s atmosphere and surface

Possible consequences of collisions of natural cosmic bodies with the Earth’s atmosphere and surface are described. The methodological basis of classification of consequences is the solution of meteor physics equations characterizing the trajectory of a body in the atmosphere, namely, the dependence of the body’s velocity and mass on the flight altitude. The solution depends on two dimensionless parameters characterizing the drag altitude and the role of mass loss by a meteoroid during its motion in the atmosphere. Depending on values of these parameters, the degree of effect on the planetary surface considerably changes. In particular, the conditions of cratering and meteorite fall on the planetary surface are obtained. The results are presented in a simple analytical form. They quite match to the real events considered in the paper. Recommendations are given on further investigations into the important problem of interaction of cosmic bodies with planetary atmospheres.