Jack McHugh, GMV; Emily Swift, GMV; James Fernandes, GMV; Juan José López García, GMV; Keiran McNally, GMV
https://doi.org/10.64861/PAFB7130
Keywords: Launch operations monitoring, uncooperative launches, direct-ascent trajectories, space-based sensors, boost-phase trajectory estimation, trajectory characterization, Space Domain Awareness (SDA)
Abstract:
Timely awareness of direct-ascent launch activity is increasingly important for Space Domain Awareness (SDA), particularly when the launching object is not cooperative and no a-priori launch notification or ephemeris is available. Direct-ascent events span a broad envelope, from ballistic missile trajectories through anti-satellite (ASAT) engagements to orbital launch vehicle ascents, each placing different demands on sensing geometry, reaction time, and processing latency. At the same time, detailed trajectory information for several classes of direct-ascent systems is sparse in open literature, complicating both sensor network design and algorithm validation._x000D_
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This work describes an end-to-end, simulation-driven framework for launch operations monitoring that couples physics-based modelling of representative direct-ascent trajectories with mission analysis of an optimized space-based sensor network and its search strategies, and a two-stage, quasi real-time characterization-and-estimation algorithm chain. First, a trajectory modelling activity identifies the key vehicle and mission design parameters that drive ascent profiles and generates a rich catalogue of simulated trajectories spanning the expected operational space. These trajectories are then used to derive sensor network requirements such as required reaction time, measurement cadence, and sensor capability/distribution, and to evaluate alternative search and pointing strategies aimed at early detection and sustained tracking during the boost phase. To support closed-loop algorithm testing, a measurement simulator converts the truth trajectories into periodic, sensor-realistic observations consistent with the designed network and sensor performance assumptions._x000D_
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Upon detection of a launch event, the first algorithm performs event characterization by analyzing the provisional ascent profile against a simulated catalogue of trajectories. It outputs a classification of the most probable launch class: ballistic missile, ASAT, or orbital launcher. This is produced together with relevant confidence metrics. The second algorithm then ingests the characterization, and quasi‑real‑time (QRT) measurements and executes boost‑phase trajectory determination, producing a continuously refined state vector and trajectory estimate (with associated covariance) over the duration of flight. The estimate is finalized at boost termination upon receipt of the last measurement, yielding a consolidated solution for the vehicle’s ascent trajectory. For orbital launcher cases, the estimated trajectory is further exploited to generate launch nominals that can seed downstream cataloguing and tracking of deployed objects. For ballistic missile-like suborbital trajectories, the characterization output can cue follow-on re-entry screening and risk assessment workflows, while ASAT characterizations can inform subsequent fragmentation or conjunction-related analyses where appropriate._x000D_
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Across these scenarios, the framework is designed to quantify key SDA-relevant metrics such as detection latency, estimation accuracy as a function of measurement cadence and sensor geometry, robustness to sparse and intermittent tracking, and classification reliability across overlapping trajectory regimes._x000D_
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By integrating sensor-network mission analysis with boost-phase estimation and post-estimation characterization, this work aims to provide a practical, reusable pathway to develop and validate launch operations monitoring algorithms for uncooperative launches under realistic sensing constraints. The resulting framework supports rapid trade studies across sensor architectures and search strategies and establishes a foundation for future incorporation into operational SDA service chains._x000D_
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Date of Conference: September 15-18, 2026
Track: Space Domain Awareness