The development of a Russian communication satellite of small class, operating in the geostationary and high-elliptical orbits

In 1994–1995 Lavochkin Association (Russia) together with the other enterprises in accordance with technical requirements of the Russian Space agency, developed a new Russian communication satellite of a small class that will operate in both the geostationary (GSO) and high-elliptical (HEO) orbits. This satellite may be injected into operational orbits using a SOYUZ-2 launch vehicle (LV) and a FREGAT upper stage (US) from Plesetsk and Baykonur space launch sites (SLS).The main reason for creating such a satellite was to decrease the cost of the support and development of the Russian communication geostationary satellites group.Russian satellites Horizont, Express, Ekran and Gals, which operate in GSO, are the basis of the space segment for communications, radio and TV broadcasting. All of these satellites are injected into GSO by the PROTON LV. PROTON is a launch vehicle of a heavy class. The use of a middle class LV instead of a heavy class will allow to reduce considerably the launch cost. The change of a heavy class LV to a LV of middle class determined one economic reason for this project. Besides, the opportunity to launch S/C into GSO from Russian Plesetsk SLS increases the independence of Russia in the domain of space communications, despite the presence of the contract with Kazachstan about the rent of Baykonur SLS. Finally, use of small satellites with a rather small number of transponders is more effective than the use of big satellites. It will allow also to increase a satellite group (by the launch of additional satellites) precisely in accordance to the development of the ground segment.     

Media reaction to a SETI success

Consideration of the reaction to a SETI detection by the media, and the effect this will have on the public, is more than mere sociological speculation. An accurate forecast of the media's interest can lead to actions that will help ensure that correct and comprehensible information reaches the public. This is most critical in the first few weeks following a discovery. While a widely accepted protocol for dealing with a detection exists in the "Declaration of Principles Following the Detection of Extraterrestrial Intelligence," it gives scant consideration to the fact that the actual situation will be chaotic and not subject to easy control. The 1996 story about the possible discovery of martian microfossils has provided a useful precedent for what will happen if astronomers uncover the existence of alien intelligence.     

Planetary Missions of the 20th Century*

Among of the highlights of the 20^th century were flights of spacecraft to other bodies of the Solar System. This paper describes briefly the missions attempted, their goals, and fate. Information is presented in five tables on the missions launched, their goals, mission designations, dates, discoveries when successful, and what happened if they failed. More detailed explanations are given in the accompanying text. It is shown how this enterprise developed and evolved step by step from a politically driven competition to intense scientific investigations and international cooperation. Initially, only the USA and USSR sent missions to the Moon and planets. Europe and Japan joined later. The USSR carried out significant research in Solar System exploration until the end of the 1980s. The Russian Federation no longer supports robotic planetary exploration for economic reasons, and it remains to be seen whether the invaluable Russian experience in planetary space flight will be lost. Collaboration between Russian and other national space agencies may be a solution.     

Space and Soviet military planning

Most of the recent discussions concerning Soviet space activities focus on the new systems and emerging technologies, particularly those with military application. How the military capabilities of these systems and technologies will be used is equally important. Their employment will be guided by current Soviet thinking and policy concerning military actions in space. This policy has its origins in Soviet military doctrine which emphasizes offensive systems. Although the Soviet space programme denies having any military objectives, it is guided by a historical link with the Soviet military and directed by decisions made within the framework of Soviet doctrine. Additional insights into Soviet thinking concerning the militarization of space can be gained from recent treaties which the Soviets have signed concerning military space activities.     

Reconfigurable dual feed antenna for direct broadcast satellites

Direct Broadcast Satellites covering large countries such as Canada, require more than one spacecraft, located at different orbital positions, as well as the use of multiple shaped beams. This would minimize eclipse requirements over several time zones, provide increased capacity by frequency reuse and permit the use of cost effective ground receivers.Two such satellites are envisaged, one covering Eastern Canada, the other Western Canada, using two different sets of three highly shaped beams. This paper is the result of a feasibility study of a satellite antenna designed such that while at either orbital location it can be reconfigured in orbit, by ground command and hence can save the cost of one additional spare spacecraft.An offset parabolic reflector is proposed for the 12 GHz downlink, with a switched “dual feed” structure, consisting of two separate but contiguous sets of pyramidal horns and their associated beam forming networks (BFN). Only one BFN set is used at any one orbital location. Detailed radiation patterns demonstrate good beamshaping capabilities, with coverage efficiencies of the order of 94%. Other considerations such as the effect of orbital locations, gain equalization and TWTA standardization are discussed.It is concluded that a satellite, reconfigurable in orbit with a “dual feed” antenna, is feasible and cost effective, for a DBS spare as well as for the main spacecraft.     

A parametric study of space transfer/upper propulsion stages

For Space Transportation System (i.e. Space Shuttle) launched satellites destined for a Geosynchronous Earth Orbit (GEO), there is a need for cost-effective, versatile propulsion systems to provide the perigee burn, i.e. to boost the satellite from Low Earth Orbit (LEO) to Geosynchronous Transfer Orbit (GTO). Surveys of commercial spacecraft activities and future GEO satellite requirements indicate that a spacecraft propulsion system that will provide the perigee burn for a broad range of future commercial satellites would have an excellent market potential.Parametric studies to investigate and define attractive perigee-burn upper propulsion systems (i.e. an Upper Propulsion Stage, or a UPS) are presented. The feasibility and payload capacilities that could be provided by a UPS assembled from essentially off-the-shelf components and subsystems, and the benefits that could be achieved by using major subsystems specifically tailored for the application are presented. The results indicate that attractive UPS configurations can be defined using either off-the-shelf or optimized major subsystems.     

Low-velocity detonations in cast and pressed high explosives

A model of low velocity detonations in charges of cast and pressed high explosives confined in metal tubes with thin walls is suggested. An analytical solution is obtained and velocities and pressures of stationary LVD waves are calculated as functions of the parameters of the wall confinement. The fraction of the total chemical energy transferred to maintain the shock wave and the average rate of reaction in the wave are estimated and the dynamics of transient predetonation processes are analysed. An explanation of the causes of the secondary shock wave formation in the transition from deflagration to normal detonations is suggested and the delay of this secondary wave is calculated and compared with experimental data.     

Transport Characteristics of Macroparticles in Dusty Plasma Induced by Solar Radiation under Microgravity Conditions

The transport characteristics of macroparticles, charged by the solar radiation under microgravity conditions, were investigated by analyzing the videorecords of experiments carried out onboard the Mirorbital station. The temperature, distributions of velocities, charge, friction coefficient, and diffusion coefficient were obtained for bronze particles.     

Numerical Simulation of Impact Loading on Solid Propellant Within an Orthotropic Shell

The strain–stress state of the solid propellant rocket engines (SPREs) is simulated under impact. The effect of orientation of elastic and strength properties of orthotropic organoplastic shell material on the strain–stress state of the solid propellant is investigated. Normal and oblique impact of single steel cylinder projectiles, both simultaneous and at different times of multiple, converging steel spheric particles with SPRE are investigated in this study. The investigation is conducted numerically. The numerical modeling was carried out in a three-dimensional formulation by the method of finite elements for the continuous approach of the mechanics of a deformable solid. The destruction of the anisotropic material is described by the tensor-polynomial criterion of the fourth degree, which takes into account the influence of hydrostatic pressure.     

RLV economics: fiscal evaluation of NASA''s reusable launch vehicle effort

The US RLV program aims to stimulate commercial development of a next-generation heavy-lift launcher and lower launch costs by one order of magnitude from the Space Shuttle. This paper discusses the incentives needed to encourage private investment — income tax relief, investment mitigation, financing assistance — in the venture and uses a specifically developed case study model to evaluate their effectiveness. It finds that an R&D tax credit would be the most practical incentive. Directions for future work are provided.