Research | Monsite

With our current technologies, we track about 25,000 objects orbiting Earth larger than 10 cm. Most of this population consists in inactive and non-cooperative man-made objects: ``space junk." Besides ethical and societal questions, they also represent an obvious orbital threat in a context of steadily increase of space traffic (SpaceX has put around 4,900 Starlink satellites since 2019). My research aims to make near Earth-space safer and cleaner by shaping space ecological and sustainable practices across different spatial and temporal scales, with emphasis on short (~ days) to long (~ decades or even longer) timescales. I foster perennial decision making practices for space situational awareness based on dynamical systems theory, astrodynamics, complexity and data-based approaches.

The Resident Space Object Network (RSONet)

With Matteo Romano and Timoteo Carletti we have introduced a new paradigm for analysing the structural properties of Resident Spasce Objects (RSOs) collisions from the complex systems perspective. Based on neighbouring relationships, the Resident Space Object Network (RSONet) connects RSOs that experience near-collisions events over a finite-time window. The structural collisional properties of RSOs are thus encoded into the RSONet and analysed with the tools of network science. This framework and paradigm allow us to use quantitative characteristics related to the RSONet to introduce indices for space sustainability criteria.

Finite time chaos indicators and numerical methods to portray chaos

I remember becoming interested in lengths during a trip back from a conference in 2018. I had however no time to work seriously on the topic before 2021. Lengths are fascinating! Take an orbit and compute its Euclidean length over a finite time window. Repeat the computation by changing the initial condition. By looking at the regularity of this application (with respect to the initial seed), you can introduce a robust, sharp and sensitive chaos indicators. No need of variational equations! Later on, I realised that the same strategy applies if, instead of the length, you deal with the extent (diameter) of the trajectory.

Resonances and chaos for space traffic management

With several colleagues, we have clarified over the years the resonant and chaotic structure of the Medium-Earth Orbits (MEOs). This region is rich dynamically speaking, due to complex resonant phenomenon involving third-bodies pertubations, i.e., the Moon and the Sun. We produced semi-analytical theories explaining many numerical simulations. In particular, we are able to predict the onset of chaos and characterize the timescales for transport.