Prototype design and testing of a Venus long duration,high altitude balloon

This paper describes the design, fabrication and testing of a full scale prototype balloon intended for long duration flight in the upper atmosphere of Venus. The balloon is 5.5 m in diameter and is designed to carry a 45 kg payload at an altitude of 55 km. The balloon material is a 180 g/m² multi-component laminate comprised of the following layers bonded together from outside to inside: aluminized Teflon film, aluminized Mylar film, Vectran fabric and a polyurethane coating. This construction provides the required balloon functional characteristics of low gas permeability, sulfuric acid resistance and high strength for superpressure operation. The design burst superpressure is 39,200 Pa which is predicted to be 3.3 times the worst case value expected during flight at the highest solar irradiance in the mission profile. The prototype is constructed from 16 gores with bi-taped seams employing a sulfuric acid resistant adhesive on the outside. Material coupon tests were performed to evaluate the optical and mechanical characteristics of the laminate. These were followed by full prototype tests for inflation, leakage and sulfuric acid tolerance. The results confirmed the suitability of this balloon design for use at Venus in a long duration mission. The various data are presented and the implications for mission design and operation are discussed.     

Electromagnetic waves observed by Venus Express at periapsis: Detection and analysis techniques

The magnetometer on Venus Express was designed to be able to obtain 128 Hz samples of the magnetic field from two sensors in a gradiometer configuration. This mode is used around periapsis to determine whether the signals reported at low altitudes near 100 Hz, had the properties of electromagnetic waves generated by electric discharges in the Venus atmosphere. The lack of a magnetic cleanliness program and the shortness of the magnetometer boom make this a challenging measurement. Fortunately the signals are sufficiently strong that they can be easily resolved with rather straightforward analysis techniques.     

On the electrodynamics of counter stream in pulsar’s inner annular cap region

The electric properties of pulsar’s inner annular gap are explored in this paper. Under two main assumptions, (1) the pulsar is alive, (2) the total charge of pulsar should not vary with time, the condition for the acceleration of negative particle in the annular region is derived. The acceleration condition is j₋ ? 0.5j₊, i.e., the current carried by negative particles is greater than or equal to 0.5 times of the current carried by positive particles. This condition holds even when the backward flow of positive particles exists in the annular region. It is noted that the outflow of negative particles offers good opportunities to understand the current closure problem of pulsar as well as wide radiation beam of pulsar observed at high energy band.     

Amplitude modulation of VLF emission and absorption of cosmic noise by <Emphasis Type="Italic">Pc</Emphasis>5 geomagnetic pulsations in the period of geomagnetic storms on October 30–31, 2003

Modulation of the VLF emission and riometric absorption by Pc5 geomagnetic pulsations is studied in the period of strong geomagnetic disturbances on October 30–31, 2003. Some conclusions about the regime of pitch-angular diffusion into the loss cone are made. The better coincidence of VLF emission modulation with geomagnetic pulsations in other longitude sectors is explained by the global character of excitation of the pulsations and by damping of their amplitudes at the meridian of observation of the VLF emission, which is associated with intensification of auroral electrojets.Translated from Kosmicheskie Issledovaniya, Vol. 42, No. 6, 2004, pp. 632–639.Original Russian Text Copyright © 2004 by Solovyev, Mullayarov, Baishev, Barkova, Samsonov.     

Radar network system to observe & analyze Tokyo Bay vessel traffic

A complete grasp of the actual vessel traffic flow by accurate observation is essential to carry out vessel traffic management, design of vessel traffic route, plan of port construction, etc. Up to now, the observation of vessel traffic has needed many efforts such as the use of a special ship or car equipped with radar observation systems and the observation staff preparation for a considerably long period. In order to perform accurate observation of vessel traffic without such efforts, the authors have developed a completely automated radar network system covering the main traffic route of Tokyo Bay. In August 2003, as the second remote radar station attaching AIS equipment was set at East Ogishima (the first was installed at the National Defense Academy in 2002), the observing range could be enlarged and cover most traffic routes in Tokyo Bay. These two radars can observe the vessel traffic in Tokyo Bay simultaneously so as to know the traffic flow accurately on the basis of analyzing the integrated radar data. In addition to the development of a radar network system, the software to analyze observed vessel traffic flow has been developed. This software has various functions such as tracking of ship's position, automatic determination of ship's size, animation of ship's movements, superposition of successive radar images, display of ship's tracks, calculation of ship's speed distribution, extraction of dangerous ship encounters using subjective judgment value and bumper model, etc. Some analyzed results on vessel traffic flow observed by the remote radars in January and September 2003 are shown in this paper.     

Lunar-based enterprise infrastructure—hidden keys for long-term business success

Discussions on the creation of lunar bases or Moon-based industrial operations tend to focus on large issues i.e. transportation, cost, and/or sustainability. But assume that the fledging lunar enterprise is successful and engenders other Moon-based operations that also grow in terms of size and scope. Could success become more problematic than failure if some often minimized, yet essential, requirements for long-term human occupation of the Moon were ignored? This paper looks at lunar operations in terms of what will be required for long-term success as participants come to view themselves as terrestrial expatriates rather than engaged in short-term duty assignments.     

Structure of the earth’s magnetosheath at small fluctuations in the interplanetary magnetic field direction

Spatial structure of the magnetosheath of the Earth was studied under the conditions when no sharp (more than 40° during 5 min) changes in the interplanetary magnetic field direction were observed. On the basis of 24 flights of the Interball-1 satellite through the magnetosheath, it is found that three regions differing from each other by parameters of the field and plasma can be observed in the magnetosheath under the above-indicated conditions. These regions also differ from the solar wind region before front of the Earth’s magnetospheric bow shock. Empirical distributions of parameters were studied in each region. Taking into account the influence of the interplanetary magnetic field direction on the processes in the magnetosheath, the cases of quasi-perpendicular and quasi-parallel shock waves were considered separately. The study showed that the distribution of parameters in the selected regions (in the solar wind before front of the bow shock, in the magnetosheath behind the bow shock (post-shock), in the region of the magnetosheath with minimal fluctuations in the field, and in the inner magnetosheath) differ from each other at any interplanetary magnetic field direction.     

On the problem of lunar radiation environment

In connection with projects of manned bases on the Moon it becomes topical to estimate radiation danger for their inhabitants. In this paper we describe a method of evaluation of the radiation environment on the lunar surface produced by galactic and solar cosmic rays. The roles of both primary and secondary radiations generated in the depth of the lunar soil under the action of high-energy protons and nuclei are taken into account. Calculated fluxes of particles are used in order to estimate annual averaged absorbed and equivalent local dose rates in tissues. It is established that in the lunar rock the contribution of secondary neutrons to the dose rate exceeds that of protons. The contribution of the secondary particles generated by nuclei of galactic cosmic rays to the dose rate is estimated.     

An algorithm for computer-aided design calculation of aircraft stability and controllability parameters

An algorithm is proposed for computer-aided calculation of required values of aircraft controlling moments and aerodynamic moment coefficients for stable fulfillment of flight trajectories specified by design flight performance.     

Analysis of static loading of a helicopter tubular skid landing gear

A three-dimensional design model of a helicopter tubular skid landing gear based on the application of the large beam displacement theory is presented. The design model takes into account special features of constructive, physical and geometrical deformation nonlinearity. The analysis of a real helicopter structure is given that confirms sufficient validity of calculation results obtained using the model developed by comparing with the results of the finite element analysis.