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A comprehensive approach to creating a control system for the shape of the radio-reflecting surface of a large-size space reflector is considered. Large-aperture space antennas are used for satellite communications and space exploration. The design of these structures is one of the most promising areas. Ensuring the specified characteristics of the reflector is directly related to maintaining the specified shape of the radio-reflective netting. Developing a control system for the shape of the active antenna surface is an urgent task. Optimizing this process makes it possible to accomplish the mission during the operational period effectively. The paper evaluates the effects of perturbations on a large-scale structure operating in outer space. A method for adjusting the geometry of the frontal network is proposed. This allows for improved communication between spacecraft and ground stations, which is very important for the safety of space flights. The conductive parts of the reflector are considered to transmit energy and control signals to the actuators. The application results of various control algorithms of the executive device making it possible to correct the netting considering the minimization of energy costs and oscillations of the structure are shown. According to the simulation results, the optimal algorithm of the target criteria hierarchy showed greater stability in terms of convergence in the presence of measurement noise and disturbances, which allows it to be applied in real time. This algorithm is supposed to be used in the future when creating a prototype of the system for controlling the shape of the radio-reflective surface of a large-size space reflector using its current-conducting structural parts. • The design of a system for setting up and maintaining a radio-reflective network fabric has been developed. • Algorithms are developed to minimize energy when setting up a radio-reflective mesh. • The optimal algorithm of the control allows solving the problem in real time. • The method for transmitting energy and control signals through the use of conductive structural parts of the reflector is proposed. [ABSTRACT FROM AUTHOR]

Abstract: The communication systems currently used on nanosatellites are usually well-proven commercial-off-the-shelf units with data rates up to 9.6kbit/s. A careful analysis shows that by using advancements in microelectronics, a higher communication performance can be achieved, even within the power and mass limitations of a nanosatellite. This paper presents a new approach to maximize the performance of nanosatellite communication systems by taking a systems engineer''s perspective and by regarding the entire satellite instead of the communication system only. It is found that efficiency can be gained by also including the electrical power subsystem in the design and having a strong interaction between the communication subsystem and the electrical power subsystem. The parameters that influence the performance of the communication system are identified. It is shown how these parameters can be tuned such that the limited resources on a nanosatellite are used most effectively. The results are used in designing the communication system of Delfi-n3Xt, the next nanosatellite mission of Delft University of Technology. The results presented in the paper can be used as a guideline to designing a nanosatellite of the next generation. [Copyright &y& Elsevier]

Abstract: Nanosatellite constellations at low Earth orbits represent a cost-efficient way for the accomplishment of Earth and space observation tasks. With the growing complexity of the exploration tasks, the amount of science data is expected to increase. For data download purposes efficient communication strategies must be adopted. The available power of a single nanosatellite spacecraft is limited by the small area of solar arrays. The communications equipment consumes a substantial amount of power. A constellation of nanosatellites allows to share resources efficiently, assigning major tasks to different spacecrafts. Within the constellation, a dedicated spacecraft which acts as data relay, monitoring and controlling inter-satellite communications is advantageous. This allows all other satellites to reuse the energy saved by implementing low-energy consuming communications links between the satellites. With this approach, taking advantage of scheduled communication contacts, the overall system performance can be maximized. For the envisaged data relay scenario, the adoption of advanced communication protocol concepts is required. This paper presents innovative solutions for the fulfilment of the described communications tasks. After an investigation of the system requirements, strategies for the interconnection of the spacecrafts for the creation of a small constellation network are provided. Suitable transport protocol implementations are investigated and efficient store-and-forward concepts are proposed. A communication architecture for the usage of a data relay satellite within the constellation is presented, describing the role of the different nodes in the network. [ABSTRACT FROM AUTHOR]

Abstract: The Ares V Cargo launch vehicle that is being designed by NASA for the Constellation Program, with its 10m diameter fairing and ability to place 130,000kg in low earth orbit, will enable telescopes with apertures much larger than the 6.5m of the James Webb Space Telescope to be placed in orbit. In this paper we revisit our designs for large aperture telescopes that could be launched with today''s expendable launch vehicles and show what aperture sizes would be enabled by the Ares V. Our assessment includes both monolithic and autonomously deployed telescopes, as well as those which could be assembled on orbit. We also address the requirements these payloads might impose on the Ares V design. [Copyright &y& Elsevier]

Abstract: The EU and ESA space research and development programmes give a consolidated model for international cooperation. They represent a good framework to develop and enhance different initiatives at global, regional and local level. The impact of space activities covers different areas of interest such as: the development of Earth observation applications for environment monitoring and risk prevention and management, the development of satellite communications and information systems, the exploitation of global satellite positioning and navigation systems, the knowledge of the Universe, the utilisation of ground segment engineering. These activities involve also the regional and local governments. This is particularly evident if we look at the competences of the European regional governments. Several European regions deal with a number of issues in areas linked to space activities. In line with these reflections a number of European regional governments supported by the Committee of the Regions launched the idea to create a Network of European Regions Using Space technologies—NEREUS. This Network is an International non-profit association (AISBL—Association International Sans But Lucratif) under Belgian law. The aim of this paper is to review the course of the initiative since its launch in April 2006, giving an update of the work done for its constitution. [Copyright &y& Elsevier]

Abstract: Space technology has the vast potential for addressing a variety of societal problems of the developing countries, particularly in the areas of communication, education and health sectors, land and water resources management, disaster management and weather forecasting. Both remote sensing and communication technologies can be used to achieve this goal. With its primary emphasis on application of space technology, on an end-to-end basis, towards national development, the Indian Space Programme has distinguished itself as one of the most cost-effective and development-oriented space programmes in the world. Developing nations are faced with the enormous task of carrying development-oriented education to the masses at the lower strata of their societies. One important feature of these populations is their large number and the spread over vast and remote areas of these nations, making the reaching out to them a difficult task. Satellite communication (Satcom) technology offers the unique capability of simultaneously reaching out to very large numbers, spread over vast areas, including the remote corners of the country. It is a strong tool to support development education. India has been amongst the first few nations to explore and put to use the Satcom technology for education and development-oriented services to the rural masses. Most of the developing countries have inadequate infrastructure to provide proper medical care to the rural population. Availability of specialist doctors in rural areas is a major bottleneck. Use of Satcom and information technology to connect rural clinics to urban hospitals through telemedicine systems is one of the solutions; and India has embarked upon an effective satellite-based telemedicine programme. Space technology is also useful in disaster warning and management related applications. Use of satellite systems and beacons for locating the distressed units on land, sea or air is well known to us. Indian Space Research Organisation (ISRO) is already a part of the International initiative called Satellite Aided Search and Rescue System. The programme to set up satellite-based Village Resource Centres (VRCs) across India, for providing a variety of services relevant to the rural communities, is also a unique societal application of space technology. The VRCs are envisaged as single window delivery mechanism for a variety of space-based products and services, such as tele-education; telemedicine; information on natural resources for planning and development at local level; interactive advisories on agriculture, fisheries, land and water resources management, livestock management, etc.; interactive vocational training towards alternative livelihood; e-governance; weather information; etc. This paper describes the various possibilities and potentials of Satcom and Remote Sensing technologies for societal applications. The initiatives taken by Indian Space Research Organisation in this direction are highlighted. [Copyright &y& Elsevier]

Abstract: India has established a ‘critical mass’ in terms of EO infrastructure for disaster management. Starting from IRS 1A in 1980s to the most recent CARTOSAT-2, India''s EO series of satellites are moving away from the generic to thematic constellations. The series of RESOURCESAT, CARTOSAT, OCEANSAT and forthcoming Radar Imaging Satellite (RISAT) satellites exemplifies the thematic characters of the EO missions. These thematic constellations, characterized with multi-platform, multi-resolution and multi-parameter EO missions, are important assets for disaster reduction. In the more specific term, these constellations in conjunction with contemporary EO missions address the critical observational gaps in terms of capturing the catastrophic events, phenomena or their attributes on real/near real time basis with appropriate spatial and temporal attributes. Using conjunctively the data primarily emanating these thematic constellations and all weather radar data from aerial platform and also from RADARSAT as gap-fillers has been a part of India''s EO strategy for disaster management. The infrastructure has been addressing the observational needs in disaster management. The high resolution imaging better than one-meter spatial resolution and also Digital Elevation Models (DEM) emanating from Cartosat series are providing valuable inputs to characterize geo-physical terrain vulnerability. Radar Imaging Satellite, with all weather capability missions, is being configured for disaster management. At present, the current Indian EO satellites cover the whole world every 40h (with different resolutions and swaths), and the efforts are towards making it better than 24h. The efforts are on to configure RESOURCESAT 3 with wider swath of 740km with 23m spatial resolution and also to have AWiFS type of capability at geo-platform to improve the observational frequencies for disaster monitoring. India''s EO infrastructure has responded comprehensively to all the natural disasters the country has faced in the recent times. As a member of International Charter on Space and Major Disasters, India has also been instrumental in promoting the related UN initiatives viz., RESAP of UN ESCAP, SPIDER of UN OOSA, Sentinel Asia of JAXA initiative and also of GEOSS initiative. The paper intends to illustrate India''s EO strategy for disaster reduction. [Copyright &y& Elsevier]