Starling Formation-Flying Optical Experiment: Initial Operations and Flight Results

Abstract

This paper presents initial flight results for distributed optical angles-only navigation of a swarm of small spacecraft, conducted during the Starling Formation-Flying Optical Experiment (StarFOX). StarFOX is a core payload of the NASA Starling mission, which consists of four CubeSats launched in 2023. Prior angles-only flight demonstrations have only featured one observer and target and have relied upon a-priori target orbit knowledge for initialization, translational maneuvers to resolve target range, and external absolute orbit updates to maintain convergence. StarFOX overcomes these limitations by applying the angles-only Absolute and Relative Trajectory Measurement System (ARTMS), which integrates three novel algorithms. Image Processing detects and tracks multiple targets in images from each satellite's on-board camera. Batch Orbit Determination computes initial swarm orbit estimates from bearing angle batches. Sequential Orbit Determination leverages an unscented Kalman filter to refine swarm state estimates over time. Multi-observer measurements shared over an intersatellite link are seamlessly fused to enable absolute and relative orbit determination. StarFOX flight data presents the first demonstrations of autonomous angles-only navigation for a satellite swarm, including multi-target and multi-observer relative navigation; autonomous initialization of navigation for unknown targets; and simultaneous absolute and relative orbit determination. Relative positioning uncertainties of 1.3% of target range (1$σ$) are achieved for a single observer under challenging measurement conditions, reduced to 0.6% (1$σ$) with multiple observers. Results demonstrate promising performance with regards to ongoing StarFOX campaigns and the application of angles-only navigation to future distributed missions.

Figures (19)

• Figure 1: An artist's impression of the Starling swarm. Credit: Blue Canyon Technologies/NASA.
• Figure 2: Definition of coordinate frames and bearing angles with VBS pointing in the $-\hat{\bm{y}}^{\mathcal{W}}$ direction.
• Figure 3: Components of target relative motion in the $\hat{\bm{x}}^{\mathcal{R}}$-$\hat{\bm{y}}^{\mathcal{R}}$ (RT) and $\hat{\bm{x}}^{\mathcal{R}}$-$\hat{\bm{z}}^{\mathcal{R}}$ (RN) planes sullivan_generalized_2020.
• Figure 4: Notional illustration of ARTMS observers and targets for a four-spacecraft system (not to scale).
• Figure 5: A high-level overview of the ARTMS flight architecture.