The 22cm gridded ion engines have already demonstrated that beam currents equivalent to a thrust level of up to 230mN can be extracted. This in turn requires a high plasma density within the discharge chamber to be produced.

The VHF Data Exchange System (VDES) is a future maritime communication system with the principal objective of enhancing maritime communication applications, based on robust and efficient digital transmission with wider bandwidth than Automatic Identification System (AIS), with a data rate up to 32 times the current AIS. As for AIS, VDES is mainly a ship-to-ship and ship-to-shore system. The ship-to-shore system will use the terrestrial VDES infrastructure that will extend the VDES coverage to only around 60 km from the shore.

Optical satellite communications play an increasingly important role in a number of space applications. However, if the system concept includes optical links to the surface of Earth, the limited availability due to clouds and other atmospheric impacts need to be considered to give a reliable estimate of the system performance. An OGS network is required for increasing the availability to acceptable figures.

Background and justification:

Bandwidth, frequency and power reconfigurable payload architectures are currently under development by major satellite manufacturers. Today's fixed bandwidth filters are a major bottle neck in such systems and have led to the implementation of reconfigurable filters. These new reconfiguration scenarios require flexible converters and, hence, flexible filters to be accommodated after the down/up conversion.

Over 120 spacecraft presently use electric thruster systems. They are now being used to provide most of the post-LEO propulsion demands on geosynchronous missions. The availability of practical, high-specific-impulse electric thrusters with long life, and the development of electrical power-systems required to sustain them, has resulted in extremely rapid growth in the applications of this technology. ESA has engaged in programmes (e.g.

The development of High Altitude Pseudo-Satellites (HAPS) has reached an outstanding level of maturity, with several flight demonstrations that augur soon to have operational capabilities. ESA, aware of the synergies among satellite and HAPS services, set up the HAPPIEST study to analyse the impact of the erruption of aerostatic HAPS into the telecommunications market, currently covered by space and terrestrial networks. Furthermore, some complementary payloads can serve interesting applications such as Earth observation and navigation services.

Implementation of the European Train Control System (ETCS) Level 2 requires that a huge amount of physical balises (known as Eurobalises), used to determine each train’s position and direction of motion, be deployed in order to support safe operation of high-speed/high-frequency train services all along the European railway infrastructure. The associated costs are substantial, which motivates the investigation of cheaper technologies.

The activity focuses on the design of an antenna architecture featuring a single reflecting surface able to generate several different beams. Several feeds can be used to illuminate a shared shaped reflector with locally modified reflection characteristics so has to form separate beams. A dedicated design procedure is required to allow an efficient antenna performance optimisation, including an initial high-level synthesis of the antenna geometry and surface layout, followed by a full-wave optimisation of the reflecting surface. The activity encompasses two steps.

Current X-Band links from Satellite to Ground for medium data rates are limited in gain and to one beam.