Duration: 12 months
The unsustainable increment of space debris in LEO orbit is growing the risk of a Kessler syndrome that might have a catastrophic impact on all existing LEO constellations. Therefore, to improve the Space Situational Awareness (SSA), this study aims at proving that future LEO mega-constellations, essentially designed to provide COM and PNT services, may also be used to monitor space debris via the integration of a GNSS-Based Passive Multistatic Radar (G-PMR) like service.
This idea dips its roots in previous works, [RD-06]-[RD-09], in which it was assessed the theoretical feasibility of using GNSS ground receivers as passive radar for space debris monitoring. In very brief:
- PROs are: MEO GNSS satellites provide a full coverage of LEO region along with a wide availability of well-known positioning signals, and a good satellite clock stability, that make them an ideal source to track LEO debris.
- CONs are: the very poor level of scattered GNSS signals received on ground as well as the uncontrolled dynamic of debris make their detection and tracking very challenging.
According to [RD-10], the above limitations can be at least partially mitigated if the G-PMR is, for instance, installed on a CubeSat, because of:
- the proximity to debris orbital layer,
- low relative velocity between illuminator and receiver,
- reduced atmospheric loss.
From this encouraging perspective, the development of a new LEO mega-constellation equipped with a PMR-like service might be a quite unique opportunity to boost space debris monitoring by also exploiting some additional advantages, e.g.:
- use of known LEO PNT/COM signals, e.g., irradiated by antenna side-lobes or higher orbit LEO sat., as high-power signal-of-opportunity to detect and track debris,
- a cooperative approach fostered by the network of LEO sat. composing the constellation,
- use of new enabling technologies (e.g., analog/digital BF, Machine Learning, cloud computing, etc.) to detect, track, and classify debris.
