A previous study (TRP Star sensing based safe mode) confirmed the interest of using star tracker as primary sensor in a generic safe mode: versatility, suitability to complex requirements and constraints (e.g.

Intentional and unintentional electromagnetic transmission can interfere with various space-borne receiving systems. Generally, such occasions are called Radio Frequency Interferences (RFI). Reports of RFI problems can be found from many space application domains that use radio receiving systems: Satellite navigation services (such as the Galileo service), telecommunications, Earth Observation, or satellite telemetry, tracking and commanding services.

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.

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 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).