PhD Thesis Defence – Guillermo Escribano

Below, you will find all the pertinent details to attend this auspicious occasion:

• Date: 22nd March 2024
• Time: 10:30 AM
• Location: EPS UC3M Leganés
• Venue: Auditorium Salón de Grados (Padre Soler)
• Online

Abstract

Earth orbits are a valuable natural resource that shall be preserved. A myriad of services rely on orbital stations, most of which support contemporary human society. To name a few, global navigation satellite services and weather forecasting, crucial for the vast majority of the population, require sensors and stations in Earth orbit. Since 2010, the space industry has seen a considerable decrease in launch and development costs, so access to space is more affordable than ever before. The latter has opened the gate for new actors in the space domain, such as startups and universities, which now operate small-sized spacecraft at low orbital altitudes. This breed of new satellites adds up to an already numerous background population, composed not only of active satellites but also derelict rockets and fragments originated from explosions and orbital collisions. It is this last subset of the Earth orbital population that alarms the space community: for a sufficiently high congestion level, a single collision can trigger a cascade of additional events to the point that every object placed in orbit is guaranteed to collide against a neighboring fragment at some future time. To prevent this catastrophic situation, the Earth orbital space is continuously monitored by surveillance networks composed of ground and space-based sensors of different types. Data acquired by these sensors is processed and fused with information coming from satellite operators to elaborate and maintain a comprehensive list, or catalog, of objects in Earth orbit. Generating a labelled map of objects can help to prevent future in-orbit collisions: by running one-to-one conjunction analyses over the entire population, it is possible to identify potentially hazardous close approaches and issue warnings to spacecraft operators so they can take remedial action. Accurately tracking space objects with surveillance sensors is a complex task, especially if it is to be done automatically. In particular, the integrity of space object catalogs is compromised when spacecraft perform maneuvers and their operators do not report them in a timely manner, mainly because automated space surveillance and tracking systems rely on natural satellite motion or relatively simple maneuver models. This doctoral dissertation advances on the tools and techniques required for automated space surveillance and tracking in the presence of unknown maneuvers, emphasizing on the definition of suitable maneuver models based on current satellite technologies.