With the world driving toward net-zero carbon emission, the space sector plays a vital role in addressing climate change and sustainability issues. For instance, satellite earth observation helps monitor natural resources and provides key data for forecasting air quality and carbon emissions; satellite navigation and communications help optimise and improve traffic management, contributing to an effective supply chain and reducing carbon emission. Besides employing space technologies as an enabler in other sectors for achieving sustainability, it is also essential to examine the sustainability agenda within the space sector itself. The European Space Agency (ESA) established the Clean Space initiative in 2012, which delivers a sustainable approach to managing space activities, aiming to minimise the environmental impact on Earth and in space. Following the triple bottom line concept, it is also vital to explore social and economic sustainability apart from the environmental aspect. Circular Economy (CE) is a concept contributing to sustainability. Stemming from sustainable manufacturing, CE was developed and pioneered by Ellen MacArthur Foundation in the UK. CE aims to eliminate waste and pollution by circulating products and materials at their highest value, which drives the efficient use of finite resources. As opposed to the "take, make, use and dispose" linear economy model, CE champions the idea of 6Rs (Reduce, Reuse, Recycle, Recover, Remanufacture and Redesign). As a result, CE profoundly impacts the value chain in an organisation's business model. The value chain in the space sector consists of the upstream and downstream segments involving various actors (stakeholders). The upstream segment covers space manufacturing activities such as launching spacecraft and satellites, which include research and development and manufacturing actors. The downstream segment comprises space applications such as activities using space data for offering products or services. Industry 4.0 is seen as an enabler of achieving sustainability. In the space sector, it is intertwined with the Space 4.0 concept. Industry 4.0, also known as the Industrial Internet of Things, refers to the cyber-physical systems where physical and virtual worlds are merged and enabled by the advancement of sensor, network and data analytics technologies. According to ESA, Space 4.0 revolutionises space activities by including more space actors from governmental to private sectors and encourages collaboration through information exchange. Existing research in other sectors has identified nine specific technologies in Industry 4.0: big data analytics, autonomous robots, simulation, horizontal and vertical system integration, internet of things, cybersecurity, cloud computing, additive manufacturing and augmented reality. Although these technological advancements have the potential to transform the value chain and contribute to developing sustainable business models, this research is still in its infancy in the space sector and no cohesive view on how Industry 4.0 could serve as an enabler in a circular life cycle for sustainability purposes in the space sector. Hence, this initial study aims to explore how Space 4.0 transforms space activities through CE for sustainability purposes. This research adopts a preliminary literature review method. The studies or reports related to this research context were collected and analysed and a number of main themes were identified based on heuristics. Finally, the thematic ontology was applied to describe the relationship between themes, contributing to a conceptual map that sets the foundation for the next phase of this research. The next phase of this research will involve a systematic literature review to expand this conceptual map. Moreover, expert interviews will be conducted to evaluate the feasibility of the themes in assessing the level of Industry 4.0 adoption in enabling this circular approach when managing space activities. The results will lead to developing a sustainability framework. Case studies will be employed to evaluate the applicability of this framework, where space actors involved in both the upstream and downstream segments will be selected. The results will inform the best practices in implementing a circular life cycle approach in managing space activities, which creates new or optimises capabilities for all space actors involved in the value chain for achieving sustainability goals.