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Mega-constellations are being deployed to offer innovative services to Earth’s users. Our work shows how they can provide seamless connectivity to LEO spacecrafts, too, and transform them into highly responsive space network nodes, thus enabling a myriad of innovative applications. For realizing the new mega-constellation services in space paradigm, in this paper we present a complete design of the LEO space terminal, suitable to any hosting platform, even CubeSats and SmallSats. By focusing on existing mega-constellations, like OneWeb and Starlink, we derive the service performance for four terminal configurations under realistic scenarios and show that Tbit/day- scale capacity is the common case for space users, by constant data dripping. Finally, we compare this new paradigm with existing services like Ground Station Networks and Data Relay Systems. All the results show that the new approach can be potentially disruptive for the space ecosystem, by transforming each satellite into a 24/7 available node characterized by high throughput, low latency, and low cost.

Global Monitoring for Environment and Security (GMES) is a joint initiative of the European Commission (EC) and the European Space Agency (ESA), designed to establish a European capacity for the provision and use of operational monitoring information for environment and security applications. ESA's role in GMES is to provide the definition and the development of the space- and ground-related system elements. GMES Sentinel-2 mission provides continuity to services relying on multi-spectral high-resolution optical observations over global terrestrial surfaces. The key mission objectives for Sentinel-2 are: (1) To provide systematic global acquisitions of high-resolution multi-spectral imagery with a high revisit frequency, (2) to provide enhanced continuity of multi-spectral imagery provided by the SPOT (Satellite Pour l'Observation de la Terre) series of satellites, and (3) to provide observations for the next generation of operational products such as land-cover maps, land change detection maps, and geophysical variables. Consequently, Sentinel-2 will directly contribute to the Land Monitoring, Emergency Response, and Security services. The corresponding user requirements have driven the design toward a dependable multi-spectral Earth-observation system featuring the Multi Spectral Instrument (MSI) with 13 spectral bands spanning from the visible and the near infrared to the short wave infrared. The spatial resolution varies from 10 m to 60 m depending on the spectral band with a 290 km field of view. This unique combination of high spatial resolution, wide field of view and spectral coverage will represent a major step forward compared to current multi-spectral missions. The mission foresees a series of satellites, each having a 7.25-year lifetime over a 15-year period starting with the launch of Sentinel-2A foreseen in 2013. During full operations two identical satellites will be maintained in the same orbit with a phase delay of 180° providing a revisit time of five days at the equator. This paper provides an overview of the GMES Sentinel-2 mission including a technical system concept overview, image quality, Level 1 data processing and operational applications.

Sentinel-1A has been launched from Kourou on a Soyuz rocket on 3rd April 2014. The second satellite Sentinel-1B is planned to be launched first half of 2016. The In-Orbit Commissioning phase was completed on 23 September 2014, followed by the so-called operational qualification phase (ramp-up). This ramp-up operations phase is a phase during which the capacity of the overall system, including the ground segment operations, is progressively increased, together with the gradual release of the operationally qualified products. The ramp-up phase is being completed at the time of writing this paper (end May 2015); at this stage the routine operations are starting. The Full Operation Capacity (FOC) of the mission will be reached once the In-Orbit Commissioning phase of Sentinel-1B and the subsequent constellation operational qualification phase will have been completed, indicatively by end 2016. The paper provides high-level information on the ongoing mission operations, at the time of the ramp-up phase completion. It described at high level the system operations, incl. ground segment operational activities, as well as some user data access statistics. It presents few examples of mission results achieved during the first year of Sentinel-1A in orbit, in some key application domains.

In line with the overall Sentinel operations strategy, Sentinel-1, the next European C-Band SAR mission following ERS and ENVISAT, will be operated based on a stable and predefined observation scenario. During the Full Operations Capacity of the mission, this observation scenario will make optimum use of the SAR duty cycle within the technical constraints of the overall system, with the main objective of satisfying the observation requirements from the GMES services and for use by ESA and EU Member States, as stipulated in the ESA GMES Space Component Programme Declaration. In addition, a secondary objective is to some extent ensure the continuity of ERS/ENVISAT SAR data exploitation. The process of collecting the Sentinel-1 observation needs (from GMES services, Member States, the scientific community, etc.) and deriving the baseline observation scenario is on-going at the time of writing this paper. The paper describes this process at high level. It provides an overview of the main types of services and applications to be supported by Sentinel-1 and their high level observation requirements, as well as the overall strategy which is followed to define the related observation scenario.

The CompSAR mission study took place in ESA concurrent design facility for the assessment design of a Passive SAR on a Small Companion Satellite flying in formation with Sentinel-1 with the goal of measuring costal currents using the back-scattered signal of the active instrument. The study highlighted the operational risks and challenges associated with close, lose formation flight. Three major areas of trade off were identified: Orbit Determination and Reconstitution, Data Downlink and TT&C scenario, and Formation Flight strategy. While for the first two areas the mapping of mission requirements to available technologies and infrastructures permits to identify adequate solutions, for the Formation Flight, a further level of analysis is required, detailing the choices for general navigation strategy implementation, nominal formation maintenance, and contingency handling. Although operational solutions for the nominal scenario are straightforward if not simple, the non-nominal scenarios bring about the fundamental problem of a possible collision risk in a relatively short delay. A careful choice of the mission geometry can provide risk mitigation, but, especially for the contingency scenarios, innovative operational strategies need be devised. To this end, three measures are identified as greatly beneficial to relax safety related constraints and increase the scientific return by simply enabling robust and safe formation flight: ad-hoc design of orbit formation configuration, on-board relative navigation, and increased ground visibility (and commandability).

The Atmospheric Dynamics Mission ADM-AEOLUS, the second Earth Explorer Core mission part of ESA's Living Planet Programme, will provide global observations of wind profiles from space to improve the quality of weather forecasts, and to advance our understanding of atmospheric dynamics and climate processes. By demonstrating new laser technology, AEOLUS is seen as an investigational mission paving the way for future meteorological satellites. A substantial decrease in the operational effort associated to the routine mission phase is one of the mission's major goals. This calls for definition of an innovative operational concept aimed at minimising ground intervention both in nominal and contingency situations. This is realised through robust mission planning and the use of both on board autonomy and operational automation in the ground systems. This paper will discuss the AEOLUS on-board autonomy in particular related to the instrument routine operations and failure recovery, present an outline of the AEOLUS Mission Planning system and provide an overview of the automation implemented in the AEOLUS Ground Systems. The AEOLUS Flight Operations Segment (FOS) is based on extensive re-use of elements developed in the context of previous Earth Observation ground segments. It is the first mission incorporating some of the latest ESA Ground Operation System (EGOS) infrastructure developments i.e. mission control system (SCOS-2000), network interfacing (NIS) and spacecraft simulator (SIMSAT), and in particular new developments in the area of control system automation (MATIS) and integrated ground station management (EMS). A summary of the overall ground segment will be provided and the FOS specific facilities required to support the mission will be discussed. The AEOLUS FOS Mission Planning System (MPS) concept will be further elaborated highlighting its simplicity of use, the modular design and its distributed complexity across the ground segment centres: FOS and Payload Data Segment (PDS). The MPS cycle and ground segment automation features will be fully described covering how the commanding and operations are planned, how the use of Automatic and Release based commanding stacks allows self-regulating TC uplink activities, how automation of ground station pass scheduling and operations is done using MATIS and how the EMS is planned to be used to support the AEOLUS routine operations.

The Global Monitoring for Environment and Security (GMES) programme main objective is to support Europe’s goals regarding sustainable development and global governance of the environment by providing timely and quality data, information, services and knowledge. To achieve this objective, the GMES programme features a Space Segment component comprising five Sentinels mission families. Scheduled for launch in 2011 and 2012, Sentinels 1, 2 and 3 represent the first step in the deployment of the GMES Space Segment. They are regarded as operational missions and as such require a high degree of reliability and availability also at the level of the ground segment while minimising the operational effort associated to the routine mission phase. This paper will describe the assumptions and constraints driving the definition of the GMES-Sentinels Flight Operations Segment (FOS). The resulting Operational Concept applied across the 3 missions will be summarised highlighting the innovative aspects, in particular the automated payload mission planning based on Orbit Position scheduled telecommands. Finally, a summary of the overall ground segment will be provided and the Sentinels FOS specific facilities, based on extensive use of ESOC ground software infrastructure, presented.

The next generation of European earth observation missions will make use of information security services to protect the mission communication infrastructure. A common security baseline denition for all these missions is currently envisaged. In this paper, we identify the security needs of such a mission, specify space and ground segment security requirements, propose a robust operational concept and identify the impact of security on the existing FOS infrastructure.

The ENVISAT satellite, launched on March 1 st 2002 by Ariane V from French Guyana, is the largest and most advanced European Earth Observation Satellite in orbit. At the time of writing, Envisat has been returning high quality environmental data for over four years. The original design lifetime of five years will be reached in March 2007, but with the spacecraft in good health, lifetime extension is foreseen. Maximising life extension depends upon maintaining robust performance and safely decreasing the rate of usage of life limiting consumables. This paper presents recent work performed on the Envisat Power FDIR (Failure Detection Isolation and Recovery) software and on the orbit control strategy. The first part of this paper describes the results of trade-off studies that led to a modification of the orbit control constraints, aimed at reduced propellant consumption. This was achieved by revisiting some of the pre-launch operational constraints with the benefit of flight experience, and a careful trade off of all the dependent factors. The first manoeuvre to use the new, more efficient strategy, was executed in January 2006. The second part of the paper focuses on the enhancements made to the Power FDIR software to reduce the number of failure cases that could lead to battery overcharge. A number of special operations performed in 2004 and 2005 are described; including a major on-board software modification, aimed at optimising the power assembly FDIR and battery charge Management algorithms. These algorithms are now in place on-board, enhancing the robustness of the power subsystem FDIR.