During this activity, a Regenerative Fuel Cell System (RFCS) was designed and constructed, comprising a high temperature Proton Exchange Membrane (HT-PEM) fuel cell stack and a High-Pressure PEM (HP-PEM) water electrolyser stack. The RFCS was tested against a three Lunar day-night cycles profile.

It is expected that the control system for the L3 mission will need to control several degrees of freedom with different actuators at different frequencies, yielding a tightly coupled, multiple-input multiple-output system. Even though the Lisa Pathfinder (LPF) mission has proven some of the control system technologies required to achieve this, the architecture of the LPF Drag Free Attitude Control System (DFACS) has been designed to best fit the motion equations and requirements of LPF, which are less challenging than those for L3.

The Doherty concept has proven to be a very effective technique for designing amplifiers, which maintain a high efficiency over a wide range of operating conditions. This technique is extensively used in terrestrial applications like base stations where power efficiency is getting more and more attention. Power efficiency is also of concern for space and the Doherty concept could certainly help in designing more efficient PAs. Ka-band is now being considered for mobile services that could offer very high capacity as compared to the existing ones at L-band.

The straylight characterisation and verification of EO instruments are quite challenging due to the stringent requirements regarding straylight and radiometric accuracy typically set for such instruments. The straylight verification generally requires an input source as an extended black (Lmin)/white(Lmax) scene with a very sharp and high contrast transition between the dark/bright region. The realisation of such a source is not straightforward as it requires careful design so as not to introduce additional straylight by its own.

Confined inhabited environment in human spaceflight imposes challeng

Background and justification:

•The railway simulation testbed is an essential tool / capability needed to support validation of GNSS receiver technologies / techniques / integrity algorithms for safety-related applications in railway

•Testbed complements field testing allowing conditions that are statistically unlikely to be observed in the field to be simulated in a highly controlled and repeatable environment

Achievements and status:

The original Ball Latch Valve was developed between 2004 and 2007, based on a Swagelok design, and between 2008 an

The activity aims at developing a tool that can investigate the failure modes of GNSS systems. Such tool can then be used for detection of failures, and/or to characterise the tolerance of GNSS system or subsystem architectures to failures. Focus will be given primarily to failures and failure modes that may impact critical services (e.g. Safety-of-Life). The tool shall be able to model GNSS systems and subsystems (i.e. ground or space segments, elements and/or components) and its failure modes in a modular way.

Increased radiation levels, as a result of space weather, has been recognised as an important risk for spacecraft and launcher operations. Recently threshold levels of solar energetic particle (SEP) flux and solar activity have been considered as a baseline criteria for launches. After the launch of Gaia in 2013, the transfer included manoeuvres reliant upon the AOCS star trackers, operating in interplanetary space and whose reliability could be seriously impacted by radiation storms known as Solar Particle Events (SPEs).