The document outlines the mission, purpose, and technical specifications of the Next Generation Ionosonde (NEXION) and Ionospheric Scintillation Total Electron Content (TEC) Observer (ISTO) as part of the Ionospheric Ground Sensors (IGS) program. IGS installs and maintains these sensors globally to characterize the space weather environment, providing data to the Space Weather Analysis and Forecast System (SWAFS)/Space Domain Awareness (SDA) Environmental Toolkit – 4 Defense (SET-4D) for modeling and forecasting ionospheric conditions. This data mitigates impacts on HF/UHF communications, radar, collection activities, and GPS services. NEXION is an unclassified, COTS unmanned vertical incidence radar that collects bottom-side ionospheric measurements, sweeping through high-frequency radio bands to produce electron density profiles. It provides global coverage from 60-1500km with specific data latency thresholds. ISTO is an unclassified, unmanned, remotely operated receive-only sensor, utilizing COTS hardware and GOTS software to measure ionospheric scintillation (S4 parameter) and TEC using GPS and UHF receivers. It is a configuration-controlled version of AFRL's SCINDA system. The document details system parameters, operations, data flow, and hardware for both NEXION and ISTO, including physical footprints and power requirements for ISTO.

The United States Space Force's Space Systems Command (SSC) has issued a Sources Sought/Request for Information (RFI) for Ionospheric Ground Sensors (IGS) Sustaining and Engineering Support. The RFI seeks to identify commercial companies capable of providing maintenance, specialized engineering support, installation, and sustainment for IGS, which includes Next Generation Ionosonde (NEXION) and Ionospheric Scintillation Total Electron Content (TEC) Observer (ISTO) systems globally. Key tasks involve site surveys, spectrum analysis, installation, cybersecurity compliance, periodic and unscheduled maintenance, troubleshooting, and system hardware/software engineering. The government is particularly interested in capabilities to sustain, install, field, and test NEXION and ISTO sites, as well as experience with similar space weather systems. Responses are encouraged from all businesses, especially small and small disadvantaged businesses, and must be submitted by January 12, 2026, to Mr. Chaz Wisuri.