The space industry aims to promote economic growth, while ensuring a sustainable use of space. The sustainability objectives of space often refer to Active Debris Removal missions, which, despite being needed, are still following a linear economic model. Space circular economy permits giving value to space debris, considering it as a valuable resource. Pilot studies investigated the application of circular concepts to spacecraft solar panels. The results of a first study on the thermal degradation behavior of the solar cell encapsulant, WACKER® RTV-S 691, identified a degradation starting at 300 °C. It demonstrates great potential for further investigation of thermal delamination processes. This paper aims to propose an experimental approach to investigate the use of solar radiation to delaminate and to anneal spacecraft solar cells using a Sun simulator with a maximum power of 1500 Wm^-2. This initial study aims to start the discussion of the implementation of circular concepts within in-space assembly and manufacturing to facilitate their implementation.

Sustainability and the need for material circularity are the main challenges the industries are facing andnot only the ones on the ground. [1][2]. Indeed, the aerospace industries are currently investigatingsolutions to implement sustainability and circularity [1][3]. The aviation sector implemented conceptsrelated to the refurbishment of engines, aircraft parts, and the repurposing of whole planes frompassenger transport to cargo and freight logistics. While the space industry still needs to develop missingtechnologies to enable circular material flows or to reuse spacecraft materials in space [1].The space industry may be late regarding the implementation of sustainability compared to other sectors.Nevertheless, it can certainly learn from other sectors, particularly from its closest sibling: the aviationindustry.The aviation industry is ahead of the space industry regarding sustainability and circularity [4][5][6],even though concepts such as reusing, repairing, and recycling are already fundamental to crewed spacemissions and some special missions such as the Hubble Space Telescope [7]. It will become even morecrucial when humanity will explore deep space going farther and farther away from Earth, from itsresources, and a potential rescue mission [1].Therefore, to succeed in the implementation of circularity in space, this paper aims to investigateprevious technology spin-offs, to understand and analyze how the aviation and the space industry learnedfrom each other to present the best practices and extract the best practices to succeed in theimplementation of circularity in space by identifying what can be transferred from aviation.

With a growing number of objects in space, the pressure to be sustainable and more efficient with resources is increasing. Driven by technological advancements, the reuse of space hardware becomes feasible and viable as alternative to spacecraft end-of-life disposal. Reuse of space hardware promises benefits in areas like mitigating space debris risks, cost reductions, and environmental sustainability on Earth and in space. However, challenges related to the space environment, like micro gravity, unknown changes due to radiation, and the energy requirements to perform maneuvers in space must be addressed in order to enable spacecraft reusability. Nonetheless, reuse of space hardware is an important objective related to long-term space exploration with implications on the human expansion into space. This paper investigates the requirements for reusability of spacecraft and if circular economy strategies can support implementing reusability for spacecraft. Based on the finding of expert interviews, it argues for design as a key enabler. It introduces design for X, design for circularity, and design for reusability, and explores how reusability of space hardware implies the need to include the space environment in design decisions.

This paper presents the progress of the KvarkenSat project, which is supported by EU ERDF Interreg funds. The goal of this project is to present the KvarkenSat mission as an example of regional economic development and competence building. KvarkenSat will carry a multi-spectral camera to analyze the status of the forests and the marine waters as well as an Automatic Identification System (AIS) receiver for sea vessel monitoring. Additionally, a GNSS receiver will be included to retrieve raw data from the GPS and Galileo constellations for advanced precise point positioning (PPP) algorithm studies. The spacecraft will also perform an in-orbit demonstration of a small green water-based thruster system for deorbit and collision avoidance purposes.

The need for material circularity and sustainability is not limited to human activities on Earth and in fact, has broad implications for the utilization of outer space. With the increased digitalization, global location and observation needs, and connectivity demands for Earth applications, an ever-growing number of spacecrafts being launched into an already “crowded” orbital space at the fast-growing risk of collisions. Sustainability, stewardship, and circularity have been identified as key concepts and enablers for the save and long-term utilization of outer space. However, as research projects related to space sustainability, recycling of spacecraft materials, and space debris mitigation gain traction, a mutual understanding of definitions and concepts is missing and the prospects and viability of circularity in space are unclear. This research attempts to fill this gap with an investigation into the possibilities to re-use spacecraft materials as an alternative to its complete disposal. A review of circularity and sustainability definitions is conducted, and this paper makes an initial effort to examine and map requirements for re-manufacturing, refurbishment, and the re-use of spacecraft materials. A literature review is conducted to identify fundamental concepts to enable circularity. This research reviews best practices and approaches in areas like aviation, electronics, and car manufacturing to thoroughly examine similarities and to create a mapping for the space sector. Following this cross-industry approach, the research surveys academic and industrial topics like spacecraft and satellite mission design, business models and product innovation, and entrepreneurship and space ecosystems to find common patterns within sectors and activities. The paper further presents findings and a preliminary roadmap and future research topics related to circularity in space.

Technological advancements and the growing demand for global connectivity is leading to an explosive growth of satellites being launched into space. Additionally, the lower cost to launch satellites into orbit makes it possible for new players to participate and to gain access to space. Decreasing launch prices and the miniaturization of payloads enables satellites being build faster and overall cheaper. In addition, instead of large satellites being launched into higher orbits, a trend towards satellite mega constellations in low-earth orbit can be observed. With this increase of new satellites already being launched and planned to be launched soon on one side, and defunct or decommissioned satellites and other space debris from collisions on the other side, concern related orbital capacity limits is being raised. Space sustainability gets more global attention and related research projects are conducted with a variety of stakeholders. This attention is needed and important but as the re-use and the recycling of satellite materials are not yet commercially viable or available, space sustainability primarily focuses on a more environmental perspective, with areas like space situational awareness and space transportation management. 

This paper investigates another option: the integration of a sustainability perspective during product design and in the production process as an alternative to the environmental perspective after launching satellites into orbit. The aim is to understand whether implementing design for sustainability and a sustainability perspective for an optimized production can support long-term space sustainability and with this, has measurable impact on the value chain for spacecraft. The research examines state-of-the-art of product design and development processes and how the space industry design and product processes are set up in comparison. Further investigation about life cycle costs variations related to a sustainability perspective, calculation approaches, and how space industry operates compared to other industries. The research will attempt to provide a top-level model for product developers with recommended procedures, activities, and the life cycle costs with options to integrate a sustainability perspective during the product design and development processes. In addition, drivers for product and production innovation through the sustainability perspective are suggested.