ONION aims at enabling mission designers and implementers to decide which Fractionated and Federated ONION concepts to develop for competitive imaging from Space
Fractionated and Federated satellite concepts are novel space systems architectural paradigms based on the distribution of functions and/or capabilities amongst several spacecraft. The fractionated spacecraft concept implies breaking down a conventional monolithic spacecraft into closely flying, yet physically separated subsystems. Such an arrangement allows for decoupling of design constraints for different instruments, increased system upgradability and responsiveness, at the cost of increased design complexity. In the case of Federated Satellite Systems (FSS) conventional spacecraft establish a network to exchange resources (such as bandwidth and computing power) for mutual benefit. Yet they retain their independent mission goals and operational independence. The Figure below presents a conceptual drawing aimed at summarising the difference between classic monolithic spacecraft, satellite formations, Fractionated systems, and ultimately Federated ones.
Both of these novel distribution concepts can support the future of EO by bringing new sensing capabilities to the table (interferometry, distributed aperture, bi-static radar…), and making the EO infrastructure more responsive and resilient. The potential benefits come with challenges at all levels, from design and architecting to specific technologies.
ONION aims at enabling mission designers and implementers to decide which Fractionated and Federated ONION concepts to develop for competitive imaging from Space, and establish the communications support requirements. This goal unfolds in 5 specific objectives:
Space-based Earth Observation has brought numerous benefits to European society with the development of applications, among others, in land monitoring, atmospheric measurements, water quality, maritime surveillance, emergency management, and Security. Compared to ground-based solutions, imaging from Space has an advantage in terms of coverage, which is potentially global, and relatively high temporal resolution. The Earth Observation market is expressing three clear needs that are pushing the European and North American industry towards new developments:
The emerging need of “coordinating observations and integrating separate observations from multiple platforms, as appropriate, to include federated data sharing standards, ontologies, and user-adopted conventions”; observations to be coordinated are multi band and multi instrument for scientific, climatic, and land management applications. The need to synchronise these data is also part of customer requests to industry. The European Commission, in its Global Earth Observation System of Systems (GEOSS) working document released in September 2014, elicits emerging needs in this sense such as the integration of observation-based models to serve user needs for spatial, temporal, and variable coverage. Likewise, the 2014 US National Plan for Civil Earth Observation, for instance, calls for “equipping and modifying existing or planned platforms for sustained, multipurpose observations”. The synergy of intents across the two continents shows the increasing importance of this emerging need. Furthermore, certain measurements of interest to the user community such as bidirectional reflectance measurements require distributed Earth Observation approaches in order to be realised.
The EO market recently exhibited an increase in need of low latency (even real time) observation data and reduced coverage gaps, not only for crisis management but also for non-critical applications. Recent European studies conducted in 2013, for instance, revealed that “more than half of Europeans would be interested in using information derived from Space-borne observations to help plan their travel and outdoor activities”. Stateside on the other hand, the Executive Office of the President National Science and Technology Council recently identified emerging societal needs in observation of complex Earth-system processes (including coupled human and natural systems), which by the nature of their timescale will need higher spatial, spectral, and temporal resolutions than what available by state of the art systems.
The increase in need of high resolution imaging outside the military domain is emerging in the EO market. A recent survey of the European EO services industry shows that a mix of optical sensors and high resolution radar is emerging in the market, with the trend pointing firmly towards higher resolution and more data for both public and commercial systems. Likewise, in a 2014 Directive of the European Parliament and of the Council, the European Commission recognises that an increasing number of Member States is investing in high resolution satellite capabilities, and recognises that “a functioning internal market for high resolution satellite data and derivative products and services would foster the development of a competitive Union Space and services industry, maximise opportunities for Union enterprises to develop and provide innovative Earth Observation systems and services, and promote the use of high resolution satellite data.”
The Consortium believes that the likely role of Fractionated and Federated Satellite Systems for competitive imaging from Space in the European context is to provide complementarity with the existing Copernicus infrastructure. Therefore, system-level requirements for ONION will be defined from the perspective of an implementation in the next generation Copernicus Space Component and the specificities of Copernicus will be assumed as part of the constraints of the systems architecture definition. In practical terms, this means that ONION could augment both the Sentinels and the Copernicus Contributing Missions.
The space segment concept envisioned by ONION is characterised by the interfaces and boundaries highlighted in the Figure below