ART-015 New Observing Strategies Testbed (NOS-T) Design and Development

The New Observing Strategies Testbed (NOS-T) is an information system infrastructure intended to conceive of, prototype, evaluate, and mature technology for novel Earth observing mission concepts. New Observing System (NOS) style missions embrace distributed and decentralized architectures that cross traditional organization boundaries, challenging existing mission and systems engineering methods and practices. To enable exploration of new concepts, NOS-T provides a communications fabric based on a lightweight Internet-of-Things messaging protocol that allows geographically distributed users to dynamically exchange structured information between NOS components in a virtual mission scenario. NOS-T hosts simulated or real-time scenario executions using cloud services hosted in a secure, managed computing environment.

This report describes the NOS-T system based on a software architecture, interface control document, and concept of operations for scenario development and execution, and outlines governance for future evolution. A companion open-source software site provides example test cases and living technical documentation which is compiled as an appendix to this report.

The NOS-T system concept follows an event-driven software architecture whereby component applications (nodes) communicate with each other using messages transmitted by the MQTT protocol. NOS-T infrastructure consists of a broker to route messages, a manager to coordinate scenario execution, and a monitor to observe and debug exchanged messages. The Science Managed Cloud Environment (SMCE) hosts NOS-T infrastructure with necessary security controls and to provide broad access in a networked cloud environment. Applications (nodes) developed and hosted by NOS-T users represent multi-domain observing platforms, communication services, forecasting models, environmental data, and other mission components.

Hierarchical MQTT topics and JavaScript Object Notation (JSON)-encoded message payloads establish interfaces between NOS-T applications. Unmanaged test cases operate in real time, like an operational mission. Status messages share information such as execution mode and local scenario time for monitoring and debugging. Managed scenarios operate in simulated time and rely on a manager to issue command messages to initialize, start, modify, or end scenario execution. Customized messages adapted to each mission scenario formalize the syntax and semantics of interactions between applications.

Example test cases demonstrate the NOS-T framework with challenging mission features such as cross-center and cross-agency collaboration, commercial spacecraft tasking, dynamic spacecraft operations, geospatial visualization, and hardware-in-the-loop testing. The central development test case considers detection and reporting of wildfire events among a space system with satellite observatories and a network of ground stations. Two collaborative pilot test cases across multiple NASA centers demonstrate monitoring, forecasting, and commercial tasking to observe hydrological events such as river flooding and burn scar-induced landslides. Other test cases demonstrate geospatial visualization and hardware-in-the-loop capabilities.

A companion open-source software library, NOS-T Tools, provides a reference implementation of key NOS-T components in the Python language, extensible applications for future test cases, and extensive documentation for new users. Future NOS-T development and refinement will rely on community-driven processes to further standardize interactions among mission components.