Abstract

Space domain awareness requires sensing modalities capable of operating across varying illumination conditions and geometries to characterize resident space objects (RSOs) in increasingly congested orbital regimes. While visible-band ground-based telescopes provide high-precision angular measurements, they are constrained by daylight, weather, and phase-angle limitations. Long-wave infrared (LWIR) sensing offers a complementary modality by observing objects through their thermal emission rather than reflected sunlight. This paper presents a pragmatic demonstration of a low-size, weight, and power (SWaP) LWIR sensor architecture designed for deployment on CubeSat platforms and its applicability to distributed thermal SSA.

The payload employs a commercial uncooled microbolometer operating in the 8–14 µm spectral band, enabling passive thermal imaging without cryogenic cooling. The sensor has been integrated into a modular CubeSat bus architecture and demonstrated end-to-end functionality, including onboard data acquisition, storage, and transmission. Airborne flight testing on a small unmanned aerial platform provided dynamic validation of radiometric stability, scene tracking, and image reconstruction under realistic motion conditions. These tests establish the operational readiness of the core sensing and data-handling architecture within CubeSat-class constraints.

Thermal observations in the LWIR band allow detection of RSOs independent of solar reflectance and enable observations during eclipse periods and low phase angles. To evaluate distributed SSA performance, constellation-geometry simulations were conducted to assess the effects of parallax-based ranging and angular diversity achievable with spatial separations on the order of tens to hundreds of kilometers. Results indicate that even modest baseline separations provide measurable parallax for LEO objects, supporting improved 3D state estimation when fused across multiple nodes.

In addition to geometric reconstruction, LWIR observations enable thermal light-curve analysis to estimate apparent temperature variations and rotational state. Multi-angle measurements improve the discrimination of surface heating patterns and enable the identification of anomalous thermal events, such as propulsion activity or localized heating. The use of uncooled sensors significantly reduces cost per node, enabling scalable distributed architectures compared to traditional cryogenic infrared systems.

The demonstrated system emphasizes practicality: commercial off-the-shelf components, minimal mechanical complexity, and compatibility with standardized CubeSat buses. The airborne demonstration validates the robustness of the sensing and processing pipeline and serves as a precursor to orbital deployment. By leveraging low-cost LWIR sensors across multiple spacecraft, the architecture enables persistent, geometrically diverse thermal observations that complement existing visible-band SSA networks

While this work focuses on pragmatic thermal SSA capability in LEO, the same distributed architecture is extensible to multi-modal missions combining thermal, visible, and additional sensing modalities within coordinated CubeSat networks. Such configurations could support broader mission objectives, including object characterization, anomaly detection, and cooperative navigation scenarios in future multi-domain space operations.