Speaker
Description
Satellite operators currently have no independent means of verifying the structural condition of their spacecraft after launch. Pre-launch MMOD risk assessments are computed from manufacturer-supplied CAD models and never updated by in-orbit measurement. Once on orbit, visibility into cumulative micrometeoroid and orbital debris (MMOD) damage is limited to whatever telemetry the satellite chooses to report — a channel designed and certified by the very party whose contractual liability is at stake. This information asymmetry is most acute in the sub-centimeter debris regime: with over 130 million particles smaller than 1 cm in Earth orbit and no ground-based radar capable of tracking them, operators accumulate structural risk that is invisible by construction.
This paper presents the micro-Y MMOD Digital Twin (MMOD-DT), a four-layer continuously updated computational system designed to close this gap through operator-owned, in-situ measurement. Its physical foundation is the NCAS (Nickel-Chromium-Aluminium-Silicon) resistive film sensor — a 65-micrometer multilayer film printed on Kapton, integrable into any spacecraft surface including MLI blankets, solar panel substrates, Whipple shield outer walls, and radiator facesheets. The sensor records cumulative structural degradation through persistent resistive change upon hypervelocity impact, providing continuous surface coverage that is radiation-tolerant beyond 100 kRad and immune to the thermal and lighting transients affecting optical and piezoelectric alternatives.
The MMOD-DT integrates NCAS telemetry with a STENVI-compliant static geometric core (L1), a real-time dynamic satellite state engine (L2), and a live space situational awareness environment feed (L3). A Bayesian update engine (L4) accumulates validated impact events to produce a continuously refined, satellite-specific posterior over the actual debris flux — systematically narrowing the 2–5× uncertainty inherent in pre-launch environment models. The output is a time-varying probability of critical damage P_c(t): an auditable, timestamped structural evidence record across the full mission lifetime.
This architecture addresses five in-orbit information gaps with direct implications for spacecraft health monitoring and collision risk management: absence of real-time impact confirmation, reliance on static pre-launch risk models, inability to independently verify as-built shielding, lack of a cumulative damage record for end-of-life decisions, and environment model uncertainty that operational experience currently never reduces.
Beyond individual satellites, aggregated NCAS data across a fleet constitutes the most comprehensive in-situ characterization of the sub-centimeter debris flux ever assembled — contributing directly to the empirical calibration of next-generation environment models such as ORDEM and MASTER, and to the evidentiary foundations of space sustainability policy.
The NCAS sensor is currently at TRL 4. A flight demonstration is planned for Q4 2026, with TRL 6 certification targeted for Q1 2027. This paper presents the system architecture, sensor operating principle, and Digital Twin computational framework, and discusses implications for spacecraft health monitoring standards and the broader space sustainability ecosystem.