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Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - ONION (Operational Network of Individual Observation Nodes)

Teaser

Summary

Over the 2018-2020 period, the EU will make important decisions with respect to the architecture and funding of the Second Generation of the Copernicus Space Component. The EU also needs to consider the evolution of the Space-based imagery market worldwide and how to adapt to the changes. The market recently accelerated with players, mainly American, with innovative EO solutions, high resolution, high revisit time imaging and full motion videos of the Earthâ€™s surface mainly based on Small Satellite platforms.
The goal of ONION is to establish design tools and methodologies for Distributed Satellite Systems (DSS) including Fractionated Satellite Systems (FSS) with a focus on Small Satellites (< 500 kg). ONION concepts contribute to the development of competitive imaging from Space and the establishment of requirements for communications support throw 5 objectives:
1. Review of the emerging Fractionated and Federated Satellite Systems (FFSS) concepts
2. Identify potential benefits coming from unmet observation needs in different EO domains
3. Identify key required technology challenges entailed by the emerging FFSS concepts, to be faced in Horizon 2021-2027
4. Validate observation needs with the respective user communities for scientific and commercial applications
5. Propose an overall strategy and technical guidelines to implement such concepts at Horizon 2021-2027
The technological and market challenges are:
- Mitigating data transfer and communication bottlenecks in EO networks
- Overcoming limited Field of View constraints in miniaturised spacecraft and instruments
- Identifying emerging observation needs and potential benefits that are unmet by existing European infrastructure
- Meeting a growing demand for EO services in a cost-effective manner
- Identifying key required ONION technologies
- Providing a comprehensive analysis of the ONION value chain
- Validating user needs identified by ONION
- Identifying the implementation strategy and technical guidelines for early value delivery of ONION tools and methodologies
ONION offers a clear added value for several stakeholders (Project partners, Copernicus-related policy makers, the international community of space systems designers and architects) and demonstrates that DSS offer a competitive solution to meet EO user needs with respect to standard monolithic large spacecraft. This finding confirms an interesting innovation trend that is taking place globally across commercial, institutional, and research players, and which could really make a difference in terms of money and time saving.

Work performed

ONION analysed user and stakeholder needs, the state of the art in Distributed Satellite Systems (DSS), architectural elements, related technological gaps, expected trade-offs, key enabling technologies, and identified 10 uses cases with a focus on Marine weather forecast (MWF); Artic Sea ice monitoring; Agricultural hydric stress; and Fishing pressure & Aquaculture, providing high revisit, high access time, and complexity of measurements requirements. The user needs and current technology maturity of the European EO infrastructure were translated into functional requirements.
Upon UAB recommendations, the ONION architecture selection process has been detailed only for the MWF and followed by a Tradespace Exploration, to filter down the possible geometries of constellations (among 104 architectures) and including ONION nodes (a spacecraft or set of spacecraft). Simulation tools were used to assess revisit time and latency parameters.
A space model-based optimisation framework (OASF) has been implemented and tailored for assessing functional characteristics and ONION mission performances, including costs, use-case requirements and high-level architectural attributes. The best ranked architectures for the MWF use case have been deeply analysed to evaluate key parameters (revisit time, data latency, on board memory evolution, power budget of each satellite, ground station contact, Inter-satellite links...). The selection process has been extended to the Agriculture Hydric stress use case.
Due to the types of instruments embarked and the nature of the potential Federated missions (Metop, Cryosat-2, Swot-Karin, etc.) the selected ONION architecture has been configured in a Walker delta constellation orbiting at 807 km, in SSO orbit, and composed of 16 nodes, distributed in 8 planes. Four of these planes encompass heavy platforms with both SAR-X and optical imager, while the other four allocated small nodes (6U type of CubeSat) with GNSS-R instruments. These two types of planes are alternatively distributed in the constellation.
Some analysis shown that the data flow and on-board data handling is not a critical point, and many satellites are in visibility of one ground station at the same time. To improve revisit time below few hours, more instruments are required, on the same orbital plane and on more orbital planes. The most critical aspect is the power budget.
The technological gap analysis presented how far is the current space market, from the ONION system defined and identified technologies needing further evolution to reach ONION requirements. The results have been presented to stakeholders, experts and wide public in workshops, with a video and public reports on the website.

Final results

For many engineering systems, the growing level of uncertainty, leads in increased system complexity and a series of new challenges in architecting such systems. These systems need to respond to changes in the market, technology, regulatory landscape, and budget available. Changes are unknown to the systems architects during the design phase but also during the concept development and requirements analysis. The ability to deal with a high level of uncertainty translates into higher architecture flexibility in engineering systems, which enables the system to respond to variations more rapidly, with less cost, or less impact on the system effectiveness.
Considering the wide range of possible applications and the limitations resulting from competitive budgets and other constraints, it is crucial to have a mean capable to prioritise cross area observations by considering both technological gaps and user needs. Introducing FSS and DSS concepts in the design of wide space constellations systems is necessary and significantly complex and not fully addressed by the specific traditional simulation tools. The ONION value proposition lies in the capacity to provide mission designers and decision makers (industry and agencies) with a powerful and end-to-end methodology and tools allowing the selection of optimal DSS architectures leveraging of specific user requirements.
Due to the inherent flexibility that comes from distributed and networked architectures, fractionated spacecraft are considered a viable solution for accommodating uncertainty in space systems. This is a leap from large, expensive, and monolithic satellite systems to a network of small-scale and less expensive free-flying satellites that communicate wirelessly. That enables incremental development and deployment, and increases system responsiveness. This approach could be valuable for supporting the design of the future generations of Copernicus Space Component. Copernicus programme including its Sentinels and Contributing Missions can be evolving into a â€˜distributed and networkedâ€™ system.