In March 2000, the Air Force Research Laboratory's (AFRL's) Space Vehicles Directorate formed the Space Weather Center of Excellence (CoE) at Hanscom AFB, MA. Concentrating the work of several branches of the directorate's Battlespace Environment Division, the CoE develops technologies for specifying, forecasting, and mitigating the effects of the space environment on Department of Defense (DoD) systems.

For over 50 years, Air Force laboratories have studied the earth's environment and the hazards posed to its systems. During this period, military operations have expanded from the traditional domains of land, sea, and air to the ultimate high ground of space, as exemplified by today's heavy reliance on space-based communications, navigation, and surveillance systems. With the expansion of operations into new geophysical domains, which is invariably driven by advances in technological capabilities, new environmentally induced complexities have arisen. For systems operating in near-earth space, these issues can range from energetic particles in the Van Allen radiation belts disrupting satellite micro-electronics to turbulence in the ionosphere degrading ground-to-space communication links. The space environment is not a static system to be measured once, corrected and forgotten. Rather, it is a dynamic 'space weather' system driven by violent solar mass ejection events and variations in ultraviolet and X-ray photon output that propagate through the interplanetary medium and hit the earth's magnetosphere causing particle energization, geomagnetic storms, and ionospheric disturbances. An excellent summary of space weather and the effects on military systems is contained in the March 2000 issue of AFRL Technology Horizons.¹

Recently the National Security Space Architect (NSSA) undertook a space weather architecture study which thoroughly explored current and future military and civilian specification and forecast needs.² A baseline architecture running the gamut from space sensors to product distribution was established to meet the perceived needs in the 2010-2025 timeframe. Subsequently, the NSSA developed a transition plan to transfer to the new architecture from the current system and is working closely with the National Space Weather Program (NSWP) to ensure cross-agency approval. The new Space Weather CoE seeks to partner with other DoD organizations, National Aeronautics and Space Administration, National Science Foundation, and National Oceanic and Atmospheric Administration to break new technological ground and prototype systems that will meet user needs as envisioned by the NSSA and NSWP.

The Space Vehicles Directorate has a robust space weather research and development (R&D) program spanning all domains: solar, interplanetary, magnetosphere, ionosphere, and thermosphere. In-house hardware and software development facilities and research expertise focus on understanding the fundamental space physics processes. This is necessary to build specification and forecast models, construct and deploy space and ground sensors, and develop operational products used in the field.

Irregularities in the earth's ionosphere, driven by solar and geophysical activity, present difficulties for DoD communication, navigation, and surveillance systems. The directorate's ionospheric research program focuses on the specification and forecasting of global electron density profiles and scintillation effects resulting from small-scale plasma turbulence. The Scintillation Network Decision Aid, which is a set of ground-based sensors and quasi-empirical models, was developed by the directorate to provide real-time alerts and short-term (< 1 hour) forecasts of scintillation impacts on ultra high-frequency satellite communication and L-Band global positioning system signals in the earth's equatorial regions. The directorate's Communication/Navigation Outage Forecast System satellite, scheduled for launch in FY03, is being developed in collaboration with the Air Force Space Test Program to provide four- to six-hour forecasts of scintillation outages.

Energetic particles in the near-earth space environment pose hazards to DoD spacecraft ranging from single-event effects to spacecraft frame charging. A major effort of the directorate's program is to develop and fly the Compact Environment Anomaly Sensor (CEASE), a small, lightweight, low-power sensor that warns satellite controllers of space particle hazards and increases situational awareness while decreasing anomaly resolution time. CEASE can also provide scientific data (given sufficient telemetry) that can be used to develop climatological models or to drive real-time specification models.

The Air Force's GEOSpace code comprises many of the models developed by the directorate and its collaborators, and serves as a 'kernel' for transitioning tailored products to space operations. The figure below shows output from the GEOSpace model, illustrating the Van Allen radiation belts using the Combined Release and Radiation Effects Satellite models, the aurora using the Defense Meteorological Satellite Program statistical models, the ionosphere using the Parameterized Ionosphere Model, and typical orbital regimes and links for DoD space systems.

Ultimately, the sun determines space weather conditions. Any attempt to forecast direct solar effects, such as solar proton or high-frequency radio absorption events, or obtain long lead-time forecasts (several days) of geomagnetic and ionospheric events requires the specification and forecast of solar activity. Consequently, the directorate maintains a research group at the National Solar Observatory in Sacramento Peak, NM, dedicated to advancing ground and space-based solar physics to meet DoD solar forecasting requirements. An advanced space-based imager, designed to detect coronal mass ejection from the sun to the earth, is being built and is scheduled for space-test in early FY02 on the CORIOLIS satellite. If successful, the Solar Mass Ejection Imager will provide one- to three-day forecasts of geomagnetic storms with a high degree of accuracy.

The Space Weather CoE is poised to meet R&D challenges posed by next-generation space weather sensing, modeling, and tailored product architecture. Working with the operators in the field, military and civilian forecast centers, and other R&D organizations, the Space Vehicles Directorate will continue to deliver affordable systems to meet the space weather specification and forecast needs of the DoD and the nation.

Written by Dr. Gregory P. Ginet of AFRL's Space Vehicles Directorate, Battlespace Environment Division, Space Hazards Branch, Hanscom AFB, MA.