Daniel O’Connell, NorthStar; Jean-Claude Leclerc, NorthStar; Noemi Giammichele, NorthStar Earth and Space; Ryan Comeau, NorthStar Earth and Space; Narendra Gollu, NorthStar; Naron Phou, NorthStar; Frederic Pelletier, NorthStar Earth & Space
Keywords: Space-based, Northstar, conops, optical,
Abstract:
On January 31st, 2024, Rocketlab launched NorthStar’s first four satellites with electro-optical payloads into Low Earth Orbit. This was the initial deployment of the very first space-based constellation dedicated to Space Situational Awareness (SSA), designed and developed by a commercial company solely through private investment. Each of the four 16U platforms hosts a 20-cm aperture payload designed to meet the NorthStar’s mission requirements. The launch was a complete success, however, during the commissioning phase, several performance issues with the satellites were encountered that significantly impacted early results. These issues have been dealt with to varying degrees, with some still ongoing. The issues encountered are limited to the sensor performance only, and have not impeded the development and deployment of NorthStar’s SSA data processing capabilities or any other aspects of its operations.
The focus of this paper will be on presenting NorthStar’s patented Concept of Operations (ConOps), tailored to the SSA mission, as well as describing the overall system design, focusing on the constellation configuration, an overview of the image processing and how observations are extracted from the raw imagery, and the end-to-end data processing pipeline. Unique aspects to be described are the multi-plane optical sensor deployment strategy which enables high revisit rates and detection capability in all orbit regimes, the employment of push-broom observation mode of the sensors (maintaining a nearly-fixed sensor orientation relative to the local orbital frame) which results in RSO’s appearing as streaks in the images discernible from the background noise and enables three-D information to be derived, and the ability of the system to ingest and process multiple third party data sources as well as the output of NorthStar’s own sensors. Additionally, some of the mitigation techniques developed to address the unique challenges encountered following initial deployment will be presented.
Technical advancements and unique features are described in several sections. The processing of the streaks that RSO’s appear as in the images produces temporal information such as relative velocity measurements, apparent magnitudes and accurate astrometric calibration. NorthStar’s continuous framing mode allows each camera to capture the star field and any Resident Space Objects (RSO’s) observations based on streak length and orientation, regardless of the orbital regime and irrespective of high relative velocities. RSO detections are derived using a combination of image processing techniques and astrodynamics that exploit the advantages of streak imagery relative to tracking, point-and-stare derived observations. The paper will also describe the creation and use of combined observables, including celestial positioning, photometry, and apparent motion.
This rich data set flows down into the orbit determination process, resulting in more precise orbit determination. More precise state vectors lead to higher confidence in object tagging, as well as better quantifying the uncertainty levels of propagated orbits. The end result is improved orbit estimates, supporting the generation of a higher quality, independent RSO catalog. Furthermore, the data is key to providing the inputs to value-added analytical products such as conjunction analysis and warning, analysis-of-intent based on pattern-of-life behavior, event detection and interpretation (e.g., maneuvers, anomalies, spawnings), and other derivative benefits. The result is actionable and timely information for customers with an associated confidence level.
Results from processing the operational data, relating to the performances of astrometric calibration, image processing, orbit determination and down-stream applications, will be presented. A performance evaluation will be presented, though it will be preliminary at this time given the sub-optimal sensor output. The paper will elaborate on the choices made by NorthStar over the process and lessons learned to demonstrate the value-add relative to existing SSA systems.
The technical details presented in the paper introduce a change in thinking in SSA capabilities through the space based SSA, together with the unique ConOps employed by NorthStar’s system. The uniqueness in terms of observational mode/strategy, data collection methodology, and processing pipeline contributes to more frequent observations and unprecedented coverage capability that is not limited by geographic restrictions, ground weather conditions, or orbit regime. This in turn improves the accuracy from astrometric calibration to precision orbit information generation. These are the benefits of a sensor array deployed in space.
Date of Conference: September 17-20, 2024
Track: Space-Based Assets