The NEBULA-Xplorer Mission (Netherlands Educational Satellite for Exploration of Binary-Linked Astrophysics) is a space mission initiated by Space Research Organization Netherlands (SRON) and carried out by students from Dutch educational institutes with the support of other industrial partners from the Netherlands. The scientific goal of the project is to observe X-ray binaries to better understand the universe and gather information that can help solve the mysteries of one of the most controversial topics in the history of science: black holes. X-Ray binaries are combinations of an extremely compact object, such as a black hole or a neutron star, and a companion star. The compact object extracts matter from the companion star, which releases great amounts of energy that can be observed using X-ray sensors. SRON has intentionally assigned the conceptual mission design to a student team as part of its objective to support the development of future space engineers and strengthen the Dutch space engineering ecosystem. This provides students with the opportunity to contribute to a mission with real scientific relevance while working within a professionally guided environment. As a result, the project has both scientific and educational purposes, which frame the scope and risk exposure in this early design phase.
Observational satellites currently observing X-ray binaries are approaching their End-Of-Life (EOL), with the final mission estimated to last until 2028. The planned future missions will only launch in the second half of the 2030s, creating a scientific gap in the observation of X-ray binaries. This critical gap can be filled with the NEBULA-XPlorer Mission with a 2030 launch date. The lack of other missions adds significant scientific value to the NEBULA-XPlorer. The mission is categorised as an European Space Agency (ESA) Mini-F Rideshare Mission. The Mini-F class encompasses small satellites with a mass range of 200-400 kg, and spacecraft mass is directly proportional to Mission and Launch Costs. As the spacecraft is a mini-satellite with very high scientific value, the mission’s total value is magnified enormously. It is also worth noting that ESA is increasingly interested in low-cost, high-return scientific missions, which align well with the NEBULA-Xplorer mission.
Another critical aspect of the mission is its aim to support and contribute to the independence of Europe’s Space Industry. While outlining the mission, the launch vehicle chosen was specifically a European launch vehicle. The Vega-C launch vehicle was selected as suitable for this mission after research into the options. Currently, Vega-C is launched only from the Guiana Space Centre in French Guiana. Therefore, this is assumed to be the only option for the NEBULA-Xplorer Mission, because a European launch site will be used. Furthermore, during the design process, European Cooperation for Space Standardization (ECSS) standards have been used to comply with the regulations for European space missions. These requirements have been extensively studied and implemented during the early design stages to prevent any complications that can occur during the adoption of the NEBULA-Xplorer Mission by ESA.

The search for extra-terrestrial life has long fascinated humanity, with Enceladus, one of Saturn's moons, emerging as a prime candidate due to hydrothermal activity and methane detected in its South Pole plumes by the Cassini mission. The ELMO orbiter is designed to explore Enceladus, searching for biosignatures, mapping its surface, and relaying data from two hopper vehicles deployed on the Saturnian moon. Carrying five scientific payload instruments, the orbiter must meet strict constraints, including a total mission cost of $750 million USD and compatibility with the Ariane 64 launcher. The spacecraft provides 6000 m/s Delta-V through a two-stage design: a main orbiter (3400 m/s) and a kick stage (2600 m/s). It also features an 85 m^2 solar array for power generation and a dual-band communication system to handle high data acquisition requirements (15% of operations time).

The lightweight truss structure, made of low-density composites, incorporates MLI for thermal regulation and multiple radiation-shielded electronics vaults. The fixed high-gain antenna ensures efficient Earth communication at Ka, X, and S bands. Weighing 13400 kg at launch, ELMO's innovative design cannot comply with the launch requirements, and it is therefore advised to perform further studies to re-evaluate the mission.