The next generation of GNSS is expected to be more demanding in terms of RF power transmission in order to guarantee a proper availability and quality of the service, hence, enhanced interference immunity and indoor positioning could be achieved.The HPA currently under development for this application are targeting power levels in excess of 300 W.

Iodine as a propellant is considered a valid alternative to xenon for electric propulsion application, in particular on Hall effect thrusters. Several advantages when using iodine as opposed to xenon can be enumerated. Iodine and xenon atomic mass and first ionization energy are very close and thruster performances, in terms of thrust density, thrust efficiency and specific impulse, have proved to be almost the same. Iodine is solid at ambient temperature and pressure, with a density about four times the density of xenon stored at 200 bar of pressure and ambient temperature.

Over the last decades, the spaceborne remote sensing community has been focused on the development of imaging radars at RF frequencies such as S-band, L-band, C-band and X-band.

ITU regulations currently permit the use of Ka-band for active spaceborne microwave remote sensing but only few missions are considering applying this frequency band such as the SARAL mission with the ALtiKa instrument (launched 2013).

The effects of propagation impairments, in particular multipath on GNSS receivers is well known, affecting availability, accuracy and continuity of service. Initial investigations on the possibility to reduce complexity of channel models for characterizing GNSS Rx in terms of tracking and/or PVT performance has been performed for example in the "GALILEO SIS TESTING" activity.Although promising results have been seen for the characterization of the statistics of the Rx, still limitations exist in this model reduction for characterising punctual fails (e.g. false lock due to high delay).

Future X-ray astronomy missions have identified a need for large area, optical filters with very high transmission in the soft X-ray portion of the electromagnetic spectrum.

Current single-frequency Satellite Based Augmentation Systems (SBAS) and planned dual-frequency multi-constellation (DFMC) SBAS systems enable approach operations with vertical guidance with time to alarm (TTA) of 6 seconds, but do not support auto land operations with decision height (DH) much less than 200 feet, and time to alarm down to 1-2 seconds . These critical TTA requirements cannot be met by having all integrity monitors centralized at the Ground Segment. Therefore, there is a need to distribute the integrity monitors amongst different Ground, Space and User Segments.

Multi-revolution Solar Electric Propulsion (SEP) transfer from the low altitude launcher injection orbit to the final operational orbit is seriously considered or already base-lined for telecom (NeoSat, Electra, Alphabus-extension), Navigation (Galileo next generation) and Earth Observation satellites. With SMART-1 significant experience has been gained to carry out these operations by a fully ground-based approach using conventional radiometric measurements. Meanwhile the boundary conditions for such operations have changed considerably. Engine technology and characteristics have evolved.

Earth Orientation Parameters (EOP) are of fundamental importance for all ESA missions. Currently, the EOPs are obtained from an external entity the Earth Orientation and Reference Service (IERS). The goal of this activity is the development of ESA capability for the estimation and prediction of Earth Orientation Parameter in order to become independent of external services. Several aspects related to this subject topic need to be investigated and further developed.

GNSS and other positioning systems are expected to have a very important role in Smart Cities. In this context, the design of the high-level architecture of a testbed to support future applications of GNSS and other positioning systems in Smart Cities is of high interest. The design of this testbed shall consider as baseline the availability of a network of distributed smart sensors, which are remotely accessible and configurable from the cloud, and existing network infrastructures shall be considered.