Society depends heavily upon a variety of technologies that are susceptible to the extremes of space weather, i.e., significant changes of the near-Earth environment that are driven by disturbances from the sun. Enhanced ionosphere currents will induce ground electrical currents that can disrupt and damage modern electric power grids and shorten the operational life of oil and gas pipelines. Solar storm-driven ionospheric density enhancements interfere with high-frequency (HF) radio communications and with navigation signals from GPS satellites.

Space weather events in the polar regions can degrade, or even completely blackout, HF communications along transpolar aviation corridors, requiring aircraft flying these routes to be rerouted to longer-distance lower latitude routes that may require refueling stops. Exposure of spacecraft during solar energetic particle events and radiation belt enhancements can cause temporary operational anomalies, damage critical electronics, degrade solar arrays and blind optical systems such as imagers and star trackers.

Because of the interconnections of key infrastructures in modern society, the impacts of severe space weather events can go far beyond disruption of existing technical systems. The impacts can lead to relatively brief, as well as to long-term, collateral social and economic disruptions.

Electric power is modern society’s cornerstone technology. It is the technology on which virtually all other infrastructures and services depend. Although the probability of a widespread electric power blackout resulting from an extreme space weather event is low, the consequences of such an event could be huge, as its effects would cascade through a wide variety of other dependent systems.

Collateral effects of a long-term power outage would likely include many of the following: disruption of the transportation, communication, banking and finance systems, and government services; the breakdown of the water distribution system owing to pump failure; and the loss of perishable foods and medications because of lack of refrigeration. The resulting loss of services for a significant period of time in even one region of the country could affect the entire nation and have international impacts as well.

Space weather forecasting services in the
United States
are provided primarily by the National Oceanic and Atmospheric Administration’s (NOAA) Space Weather Prediction Center (SWPC) and the U.S. Air Force’s Weather Agency.

These entities work collaboratively to address the needs of their civilian and military user communities, respectively.

The SWPC draws on a variety of data sources, both space- and ground-based, to provide forecasts, watches, warnings, alerts and summaries as well as operational space weather products to civilian and commercial users. Its primary data sources include NASA’s Advanced Composition Explorer (ACE), NOAA’s geostationary and polar orbiting satellites, magnetometers, and the Air Force’s Defense Meteorological Satellites Program satellites and solar optical and radio observing networks. Other sources include a variety of NASA scientific satellites as well as a number of ground-based facilities.

Monitoring and forecasting space weather has become an essential component for the successful operation of technical systems in space and on Earth’s surface. The science-driven ACE spacecraft has monitored the solar wind and energetic particles at the upstream Lagrangian point (L1) since its launch in August 1997. Its nearly continuous data set from 1.5 million kilometers away from the Earth has revolutionized space weather forecasting and alerting functions for the
United States
. And yet, ongoing and future capabilities for such monitoring by the
United States
are highly uncertain.

In its 2006 report, the Assessment Committee for the National Space Weather Program (NSWP) warned that continued reliance on science-driven programs for L1 data could result in serious disruption of such information for forecasting and mitigation purposes as well as the reliance on non-U.S. sources for such data. “Many … in situ space weather data are … obtained from primarily science-driven satellite programs,” noted the committee.

NASA is to be lauded for placing an instantly signaling space weather beacon on ACE, and NOAA for demonstrating its important utility. However, reliance on NASA for monitoring may be propagating complacency regarding the future of L1 data when ACE becomes inoperative – its minimum design life was two years, with a five-year goal. Even if current ACE fuel consumption for orbit and antenna pointing maneuvers are maintained, estimated at about 2024 at present, it is impossible – especially for an older operational spacecraft – to predict instrument degradation and when – or if – a random failure could limit or halt ACE space weather operations.

It is imperative that the
United States
develop and deploy dedicated operational data acquisition platforms rather than continuing to rely heavily on limited-life science missions for space weather purposes. This is particularly important for a function as crucial to the overall NSWP architecture as L1 solar wind monitoring.

Possibilities for addressing this L1 need range from publicly funded missions of various capabilities and mission sizes, to privately funded missions that would sell data for practical uses. Among the former, it has been a continuing goal of NOAA to obtain funding and full programmatic approval for an operational L1 monitoring capability that could eventually replace NASA spacecraft such as ACE. The instrumentation on dedicated space weather platforms would not in general require the sophistication, and hence the cost, of instruments on specialized science missions, and the platforms themselves could also likely be smaller and simpler to implement.

We urge that the Office of Science and Technology Policy in the executive office of the president, Congress, NOAA, and all parties – public and private – involved in space weather programmatic planning place high priority on supporting the design, development and deployment of a continuing series of dedicated L1 space weather monitoring spacecraft. To do less would diminish irreparably our nation’s space weather posture.

Daniel N. Baker is professor of astrophysical and planetary sciences and director of the Laboratory for Atmospheric and Space Physics at the

. Louis J. Lanzerotti is Distinguished Research Professor at the New Jersey Institute of Technology and editor of the technical journal Space Weather. Both were members of the Assessment Committee for the National Space Weather Program.