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1.
Andrea Franzolin   《Space Policy》2009,25(3):193-194
Around 50 leaders and experts from space industry, governmental and financial institutions participated in an ESA conference on “The Future of Public–Private Partnerships in Satellite Communications” in Vienna in March 2009. An increasing portion of commercial and institutional space projects are operated under the provisions of service contracts, with public–private partnerships (PPPs) becoming a significant source of financing for space programmes. The conference was based on a study initiated by ESA and performed by Euroconsult, Milbank and ESPI, outlining the main perspectives of modern PPP models in the European satellite communications sector.  相似文献   

2.
Bandwidth is an expensive and scarce resource, thus its efficient exploitation is of paramount importance. Recent communication satellites feature sophisticated spatial access strategies through spot beams providing this way a total throughput in the range of 100 Gbit/s. Next generations of communication satellites, as postulated in the Satellite Communications Network of Experts (SatNEx) III, a project funded by the European Space Agency (ESA) for advanced research in satellite communications, require technological developments to achieve the Tbit/s region. Multibeam architectures formed by a central gateway, a multibeam satellite, and an aggressive frequency reuse strategy can meet such ambitious design goals. Interference problems are tackled by appropriate countermeasures such as (joint) precoding and beamforming on the forward link as well as multi-user detection on the return link; these methods require accurate and timely knowledge of the channel state, which in turn necessitates suitable algorithms for channel estimation. This paper addresses performance issues related to channel state estimation on the symbol-synchronous forward link and the frame-synchronous return link. It highlights for both directions the potential performance gain by assuming a priori knowledge of the user position, in this context referred to as location-aware channel estimation.  相似文献   

3.
Advantages of communications satellites are the inherent broadcast capability, high bandwidth, reliability and flexibility in network expansion. Small transportable terminals can be made operational very quickly. Recent developments in communications and computer technology allow to provide low-cost equipment, which is affordable even in developing countries. Communications satellites can also play an important role in case of emergencies or natural disasters. The combination of satellite communications and navigation can support new services for emergency teams.

At the Institute of Applied Systems Technology and the Institute of Communication Networks and Satellite Communications highly transportable terminals have been developed, both for star and mesh network topologies. A fully meshed VSAT system is used for symmetrical links. For other applications, which do not require high return link capacity an asymmetrical system is an efficient solution. It uses low-cost DVB technology for the forward link and satellite phones with data capability on the return link. Novel multicast protocols allow to use these asymmetrical links in an efficient way. The paper describes the different systems and their applications in disaster management and security applications. Emphasis is put on transfer of remote sensing images and voice over IP (VoIP) as well as videoconference services.  相似文献   


4.
The European spacesuit system (ESSS) initiated by the European Space Agency (ESA) in the late 1980s had many similarities with the Soviet/Russian ORLAN spacesuit system, due to the Hermes system requirements. First, direct contacts in 1989 permitted closer comparison of the two suit systems, and soon the ORLAN manufacturer Zvezda could be contracted as support to the European spacesuit team. In particular, the suit enclosure design and predevelopment testing and operational analysis were performed in close cooperation between Zvezda and the European team under Dornier.

With the changing system requirements and a closer cooperation between ESA and the new Russian Space Agency (RKA) a new joint spaceplane/stations mission scenario came about. This scenario could be served by one spacesuit system, EVA SUIT 2000, which was to be jointly developed by a team headed by Zvezda and Dornier for ESA and RKA. ORLAN-DMA and ESSS experience and hardware were the initial platforms for these activities to create a new generation spacesuits for the Mir 2 and later the ISSs.

A suit demonstrator was manufactured and tested by the end of 1994 when ESA stopped its spacesuit development activities and the joint EVA SUIT 2000 project was terminated. However, many of the features designed, manufactured and tested for the EVA SUIT 2000 were then implemented by Zvezda in the new Russian spacesuit system ORLAN-M, now in full operation onboard the ISS.  相似文献   


5.
The European Space Agency (ESA) contribution to the International Space Station (ISS) goes much beyond the delivery of hardware like the Columbus Laboratory, its payloads and the Automated Transfer Vehicles. ESA Astronauts will be members of the ISS crew. ESA, according to its commitments as ISS international partner, will be responsible to provide training on its elements and payloads to all ISS crewmembers and medical support for ESA astronauts. The European Astronaut Centre (EAC) in Cologne has developed over more than a decade into the centre of expertise for manned space activities within ESA by contributing to a number of important co-operative spaceflight missions. This role will be significantly extended for ISS manned operations. Apart from its support to ESA astronauts and their onboard operations, EAC will have a key role in training all ISS astronauts on ESA elements and payloads. The medical support of ISS crew, in particular of ESA astronauts has already started. This paper provides an overview on status and further plans in building up this homebase function for ESA astronauts and on the preparation towards Training Readiness for ISS crew training at EAC, Cologne. Copyright 2001 by the European Space Agency. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission. Released to IAF/IAA/AIAA to publish in all forms.  相似文献   

6.
Bi-directional ground-to-satellite laser communication experiments were successfully performed between the optical ground station developed by the National Institute of Information and Communications Technology (NICT), located in Koganei City in suburban Tokyo, and a low earth orbit (LEO) satellite, the “Kirari” Optical Inter-orbit Communications Engineering Test Satellite (OICETS). The experiments were conducted in cooperation with the Japan Aerospace Exploration Agency (JAXA), and called the Kirari Optical communication Demonstration Experiments with the NICT optical ground station (or KODEN). The ground-to-OICETS laser communication experiment was the first in-orbit demonstration involving the LEO satellite. The laser communication experiment was conducted since March 2006. The polarization characteristics of an artificial laser source in space, such as Stokes parameters, and the degree of polarization were measured through space-to-ground atmospheric transmission paths, which results contribute to the link estimation for quantum key distribution via space and provide the potential for enhancements in quantum cryptography on a global scale in the future. The Phase-5 experiment, international laser communications experiments were also successfully conducted with four optical ground stations located in the United States, Spain, Germany, and Japan from April 2009 to September 2009. The purpose of the Phase-5 experiment was to establish OICETS-to-ground laser communication links from the different optical ground stations and the statistical analyses such as the normalized power, scintillation index, probability density function, auto-covariance function, and power spectral density were performed. Thus the applicability of the satellite laser communications was demonstrated, aiming not only for geostationary earth orbit-LEO links but also for ground-to-LEO optical links. This paper presents the results of the KODEN experiments and mainly introduces the common analyses among the different optical ground stations.  相似文献   

7.
The American idea of a Solar Power Satellite was proposed for the first time in 1968 by Peter Glaser in a famous article in Science. This concept has since been the subject of many theoretical studies, and of some limited practical studies (mainly about microwave energy transmission) in the USA with funding from NASA and the Department of Energy (DOE). Some evaluations have been also conducted in Western Europe, particularly within the European Space Agency (ESA). But very little is generally known about the attitude towards SPS of the second main space power: the USSR. Soviet literature on SPS is much less abundant, but it does exist. Very interesting articles on the subject have been written by leading Soviet space experts. Some of these articles are analysed here, and the practical meanings of the ex[ressed opinions, generally very favourable, are investigated in view of the growing Soviet space capability.  相似文献   

8.
《Acta Astronautica》2010,66(11-12):1520-1529
Today's space operations involve co-working of people with different ethnical, professional and organisational backgrounds. The aim of this study was to examine the implications of cultural diversity for efficient collaboration within the European Space Agency (ESA), and between ESA employees and representatives from other agencies. ESA employees from European countries (N=576) answered to the CULT Ground Survey. The results showed that differences in relation to leadership and decision making were the most important issues thought to interfere with efficient co-working within ESA, and between ESA employees and colleagues from other agencies. Employees who collaborated with more than three nationalities within ESA indicated most challenges in co-working due to differences in compliance, behavioural norms and competitiveness. Challenges in co-working differed between agencies, and these differences were consistent with value differences in the national populations. The results may have applied value for training of European employees working in international space program teams.  相似文献   

9.
Hispasat Advanced Generation 1 (HAG1) is the first satellite using the SGEO platform, which is under the development in the ESA Artes-11 program. Since the last presentation in the IAC 2007, a European industrial consortium led by OHB has completed the mission and spacecraft design. The platform Preliminary Design Review has been carried out in May 2008. The customer for the first mission is a commercial operator—Hispasat. The contract was signed in December 2008 and the satellite will be launched in 2012. To give confidence to the customer, SGEO platform will use up to date flight proven technologies. HAG1 carries 20/24 Ku-band and 3/5 Ka-band transponders to provide commercial services. Some innovative payload technologies will also be flown on board of HAG1 to gain in-orbit heritage. SGEO has also been selected as the baseline platform for the ESA Data Relay Satellite (EDRS). Phase-A study has just kicked off in January 2009. The targeted launch date is 2013. Heinrich Hertz will also use the SGEO platform. Heinrich Hertz is funded by the German Space Agency (DLR) and provides flight opportunities for technologies and components developed by the German Space Industry. With the HAG1 contract in hand, and EDRS and Heinrich Hertz in the line, OHB with its partners has the confidence that it will be able to speed up the product development of the SGEO platform for potential customers in the commercial market. This paper will first present the updated platform design and the status of the product development will be followed with the introduction of innovative payload technologies on board the first mission—HAG1 and ended with the mission concepts of EDRS and Heinrich Hertz missions.  相似文献   

10.
Today's space operations involve co-working of people with different ethnical, professional and organisational backgrounds. The aim of this study was to examine the implications of cultural diversity for efficient collaboration within the European Space Agency (ESA), and between ESA employees and representatives from other agencies. ESA employees from European countries (N=576) answered to the CULT Ground Survey. The results showed that differences in relation to leadership and decision making were the most important issues thought to interfere with efficient co-working within ESA, and between ESA employees and colleagues from other agencies. Employees who collaborated with more than three nationalities within ESA indicated most challenges in co-working due to differences in compliance, behavioural norms and competitiveness. Challenges in co-working differed between agencies, and these differences were consistent with value differences in the national populations. The results may have applied value for training of European employees working in international space program teams.  相似文献   

11.
Poland has a long-standing tradition in space activities. Polish institutions have participated as co-investigators in almost all European Space Agency (ESA) science projects, as well as on many other missions. However, the first Polish satellite (PW-SAT) was only launched in 2012. Poland was one of the first Eastern European countries to conclude a Cooperation Agreement with ESA in the peaceful use of outer space; it was signed in 1994 and followed by a second in January 2002. Negotiations on Polish membership in the ESA were started in autumn of 2011, and ended in April 2012. Following ratification of the agreement, Poland officially became the 20th Member State of ESA on 19 November 2012. This article examines how Poland is setting its way as a space nation. It describes recent developments in the Polish space programme, including the road to Poland's full membership in the European Space Agency.  相似文献   

12.
The primary objective of the Laser Interferometer Space Antenna (LISA) mission is to detect and observe gravitational waves from massive black holes and galactic binaries in the frequency range 10−4 to 10−1 Hz. This low-frequency range is inaccessible to ground-based interferometers because of the unshieldable background of local gravitational noise and because ground-based interferometers are limited in length to a few km. LISA is an ESA cornerstone mission and recently had a system study (Ref. 1) carried out by a consortium led by Astrium, which confirmed the basic configuration for the payload with only minor changes, and provided detailed concepts for the spacecraft and mission design. The study confirmed the need for a drag-free technology demonstration mission to develop the inertial sensors for LISA, before embarking on the build of the flight sensors. With a technology demonstration flight in 2005, it would be possible to carry out LISA as a joint ESA-NASA mission with a launch by 2010 subject to the funding programmatics. The baseline for LISA is three disc-like spacecraft each of which consist of a science module which carries the laser interferometer payload (two in each science module) and a propulsion module containing an ion drive and the hydrazine thrusters of the AOCS. The propulsion module is used for the transfer from earth escape trajectory provided by the Delta II launch to the operational orbit. Once there the propulsion module is jettisoned to reduce disturbances on the payload. Detailed analysis of thermal and gravitational disturbances, a model of the drag-free control and of the interferometer operation confirm that the strain sensitivity of the interferometer will be achieved.  相似文献   

13.
After a large consultation with the scientific and industrial communities in Europe, the Aurora Space Exploration Programme was unanimously approved at the European Space Agency (ESA) Council at ministerial level in Edinburgh in 2001. This marked the start of the programme's preparation phase that was due to finish by the end of 2004. Aurora features technology development robotic and crewed rehearsal missions aimed at preparing a human mission to Mars by 2033. Due to the evolving context, both international and European, ESA has undertaken a review of the goals and approach of its exploration programme. While maintaining the main robotic missions that had been conceived during Aurora, the European Space Exploration Programme that is currently being proposed to the Aurora participating states and other ESA Member States has a reviewed approach and will feature a greater synergy with other ESA programmes. The paper will present the process that led to the revision of ESA's plans in the field of exploration and will give the current status of the programme.  相似文献   

14.
A study was performed to determine the probability of collision with resident space objects and untrackable debris for the tether component of the Tethered Satellite System (TSS) after it broke away from the space shuttle orbiter (mission STS-75) in February 1996. Both an analytical and a numerical approach were used in this study, and the results obtained with these two methods were found to be in good agreement. These results show that the deployed tether is expected to have been impacted by several particles 0.1 mm or larger in size. The probability of collision with objects 10 cm in size or larger was on the order of 10−3 per month. Since the severed tether reentered within one month after deployment, the collision hazard to other objects while in orbit was small. The analytical methods used in this study are general and can be applied to future tether collision evaluations.  相似文献   

15.
Skoog AI 《Acta Astronautica》1982,9(12):727-740
The delivery of fully qualified Environmental Control and Life Support System (ECLS) flight hardware for the Spacelab Flight Unit was completed in 1979, and the first Spacelab flight is scheduled for mid 1983.

With Spacelab approaching its operational stage, ESA has initiated the Follow-on Development Programme. The future evolution of Spacelab elements in a continued U.S./European cooperation is obviously linked to the U.S. STS evolution and leads from the sortie-mode improvements (Initial Step) towards pallet systems and module applications in unmanned and manned space platforms (Medium and Far Term Alternatives).

Extensive studies and design work have been accomplished on life support systems for Life Sciences Laboratories (Biorack) in Spacelab (incubators and holding units for low vertebrates).

Future long term missions require the implementation of closed loop life support systems and in order to meet the long range development cycle feasibility studies have been performed. Terrestrial applications of the life support technologies developed for space have been successfully implemented.  相似文献   


16.
The arts offer alternative insights into reality, which are explored by science in general, and broadened by the activities conducted by the European Space Agency [4] and other space agencies. Similar to the way the members of ESA are ambassadors for spaceflight and science, artists and cultural professionals are ambassadors for human expression, experimentation, and exploration. In June 2011, the ESA Topical Team Arts and Sciences (ETTAS) held a three-day workshop at the European Astronaut Centre in Cologne, Germany. During this workshop, topics and ideas were discussed to develop initiatives between the arts, sciences and ESA. The aim was to foster and expand the human and cultural aspects of space exploration, and at the same time offer a means of communication that aims to reach audiences beyond the scope of traditional space-related channels. The consensus of the team was that establishing and sustaining a transdisciplinary professional community consisting of ESA representatives, scientists and artists would fuel knowledge transfer, and mutual inspiration. Potential ways to provide a sustainable cooperation within and between the various groups were discussed. We present the preliminary findings including a number of measures and mechanisms to initiate and conduct such an initiative. Plausible organisational measures, procedures and consequences, as well as a proposition on how to proceed are also discussed. Overall, the involvement and cooperation between the arts, space science research and ESA will enhance in the citizens of the ESA member states the sense of public ownership of ESA results, and participation in ESA?s research.  相似文献   

17.
《Acta Astronautica》1987,15(3):181-187
QUASAT is a joint ESA/NASA cooperative mission for a free-flying VLBI antenna to be used with the U.S. and European ground arrays. The spaceborn reflector shall have a diameter of 15 m or more and shall operate at three frequencies: 1.6, 5 and 22 GHz. These requirements are very stringent and very difficult to satisfy. The reflector proposed by the European Space Agency as part of the Quasat assessment study shall be presented. Such reflector shall use the Inflatable Space Rigidized technology under development within ESA. Results of the performances envisaged from such design shall be discussed together with the manufacturing and testing problems envisaged for such reflector. Results derived by different reflector design but using the same Inflatable Space Rigidized technology shall also be presented.  相似文献   

18.
This paper describes the research and development of an On-Board Processor (OBP) for a mobile satellite communications system using a geostationaly satellite. The system, which based on Multi-Carrier Time Division Multiple Access, can realize high performance and facilitate the use of miniature hand-held mobile Earth terminals.

Our research and development results indicate as follows.

1. 1) The simultaneous-slot switching method will be the most suitable for an on-board base-band switching with consideration of traffic capacity, time delay, and hardware scale.
2. 2) The OBP performs channel exchange with regeneration that contributes to a reduction in the size of mobile terminals because of the coding gain.
3. 3) Many kinds of Application Specific Integrated Circuits are designed to realize large channel capacity and reduce the size and power consumption of the OBP. These OBP design can increase the channel capacity, which is equivalent to in 5.6kbps voice channel, up to over 500 channels within 5MHz frequency band

Some results are applied to the OBP being developed for the Japanese Engineering Test Satellite VII (ETS-VB).  相似文献   


19.
Space-based astrometry has a great tradition at ESA. The first space-based astrometric satellite in history, “Hipparcos”, was launched by ESA in 1989 and, in spite of orbital problems, was able to accomplish almost all of its tasks until it was finally shut down in 1993. The results of the Hipparcos mission were published by ESA in 1997 in the form of six CD-ROMs: the Hipparcos Catalogue contains 118,218 entries with median astrometric precision of around 1 milliarcsec, and specific results for double and multiple systems. In practice, Hipparcos drew for the first time the three-dimensional “map” of the spherical region of the Galaxy surrounding the Sun and having a radius of roughly 1,000 light years.

Then, in 1995, ESA launched the study of a new astrometric satellite, named “GAIA” and about a hundred times more powerful than Hipparcos, i.e. with median astrometric precision of around 10 microarcsec. This new satellite is intended to measure the parallaxes of over 50 million stars in the Galaxy, at least for the brightest stars, and this would mean to “draw” the three-dimensional map of the whole Galaxy, reaching out even to the Magellanic Clouds, 180,000 light years away.

The team of European scientists and engineers now designing GAIA, however, is facing hard technological difficulties. One of these is the design and coding of radically new and ultra-powerful mathematical algorithms for the on-board compression of the 50-million-stars data that GAIA will send to Earth from its intended geostationary orbit. Preliminary estimates of the raw data rates from the GAIA focal plane, in fact, are of the order of a few Gigabits per second. To reduce the data stream to the envisaged telemetry link of 1 Megabit per second, on-board data compression with a 1 to 1,000 ratio is the target. Clearly, this is far beyond the capabilities of any lossless compression technique (enabling compression ratios of 1 to some tens), and so some “wise” lossy compression mathematical procedure must be adopted.

In this paper a GAIA-adapted lossy data compression technique is presented, based on the Karhunen-Loève Transform (KLT). The essence of this method was already used by NASA for the Galileo mission when the large antenna got stuck and the mission was rescued by re-programming the on-board computer in terms of the KLT. That transform was officially named ICT — “Integer Cosine Transform” — by the NASA-JPL team led by Dr. Kahr-Ming Cheung. But the KLT here described for GAIA will of course differ from the JPL one in many regards, owing to the advances in computer technology.

Finally, estimates are also given about the possibility of using the KLT for onboard data compression in case GAIA is going to be put into orbit around the Lagrangian point L2 of the Earth-Sun system, and, above all, in case the number of stars to be observed is actually raised from 50 millions to one billion, as ESA currently appears to be likely to pursue.  相似文献   


20.
On 16 November 2000, the Council of the European Space Agency (ESA) meeting at Ministerial level and the European Research Council of the European Union (EU) gathered in Brussels to adopt in parallel two resolutions on a European Strategy for Space. This political impetus indicates a clear motivation to support the further development of the European space sector, based on a much closer collaboration between the two European institutions, thereby exploiting their respective competencies and synergies. This paper presents some Spanish viewpoints relative to the common European Strategy for Space of the EU and ESA. Spain is supportive of the new strategy and the paper describes how its co-ordinated approach could be translated into action across various European programmes.  相似文献   

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