Speaker
Description
Within the last two decades, the number of objects in Earth orbits increased from around 7500 to more than 30000 in 2023. The current satellites heavily rely on one-time use. To prevent further congestion of crucial orbits, more sustainable practices for space use are imperative. Refuelling satellites in orbit extends their lifespan and reduces debris accumulation by decreasing the number of defunct satellites from fuel depletion. GEO satellites, allocating about 50% of their mass to propellant, are prime candidates for On-Orbit Refuelling (OOR) due to their durability, limited slots, and high investment, offering potential cost savings and increased utility.
This on-going project aims to design an OOR infrastructure tailored to service GEO satellites close to their End-of-Life (EOL) expecting depletion of onboard reserves. The infrastructure consists of a fuel depot and servicing spacecrafts for in-space propellant transport. For a given set of GEO clients, selected launcher, servicer and depot design, the work optimizes the OOR scenario. It suggests various mission architectures with different fuel depot locations and numbers of servicers.
The OOR design is the outcome of an iterative design procedure. Deployment, and operation of the servicing architecture are simulated. Trajectories of servicers to rendezvous with clients are the result of a cost($\Delta v$)-duration trade-off. The logistics optimization problem is formulated as a Capacitated Vehicle Routing Problem (CVRP), and a tailored genetic algorithm minimizes mission cost or duration for routing decisions.
The developed procedure allows to evaluate OOR mission infrastructures for feasibility and performance for variable client satellites and mission constraints, enabling comparison of various infrastructures to guide preliminary system of systems design. It could assist in establishing a sustainable European logistics ecosystem for long-term servicing strategies through combining multiple refuelling missions and expansion to other servicing tasks.
