The availability of timely and reliable space-based information about our environment underpins elements of the infrastructure that are critical to a modern society. From economic and societal perspectives, reliable knowledge on a range of timescales of conditions in the geospace environment (including the mesosphere, thermosphere, ionosphere, exosphere, geocorona, plasmasphere, and magnetosphere) is important for multiple applications, prominent among them utilization of radio signals (which enables increasingly precise navigation and communication), as well as mitigation of deleterious effects such as drag on Earth-orbiting objects (which alters the location of spacecraft, threatens their functionality by collisions with debris, and impedes reliable determination of reentry). In addition, energetic particles can damage assets and humans in space, and currents induced in ground systems can disrupt and damage power grids and pipelines, a topic that has been a focus of recent research (Box 7.1).
Moreover, society expects and relies on instant coverage of events, the ability to communicate to remote corners of the world, and the availability of geospatial information needed for national security and other purposes. However, the space-based technologies that provide this information are vulnerable to the conditions in the dynamic and complex space environment through which radio waves propagate and where satellites orbit. In this chapter, the survey committee presents its vision for a comprehensive program consisting of observations, models, and forecasting, enhanced beyond current capabilities, to help protect these critical technologies.
Understanding space weather and climate is a prerequisite for fulfilling at least two directives of U.S. national space policy:1
1. “Take necessary measures to sustain the radiofrequency environment in which critical U.S. space systems operate.” Societal use of the radio wave spectrum is growing dramatically, but its reliability and
1 “National Space Policy of the United States of America,” June 28, 2010, available at http://www.nasa.gov/pdf/649374main_062810_national_space_policy.pdf.
BOX 7.1 PREDICTING GEOMAGNETICALLY INDUCED CURRENTS ON THE POWER GRID: AN EXAMPLE OF A CRITICAL NATIONAL NEED
A geomagnetic storm is caused by energetic streams of particles and magnetic flux that originate from the Sun and impact and distort Earth’s magnetic field. The transient changes in Earth’s magnetic field interact with the long wires of the power grid, causing electrical currents to flow in the grid. The grid is designed to handle AC currents effectively, but not the DC currents induced by a geomagnetic storm. These currents, called geomagnetically induced currents (GICs; also known as ground-induced currents), cause imbalances in electrical equipment, reducing its performance and leading to dangerous overheating.1
Solar and space physicists, working with bulk power grid engineers, have helped to create the capability to model the effects of GICs on electricity transmission and distribution systems. This crucially important work relies on a body of knowledge built up over years of study. Today, sophisticated modeling software is used to assess the response of the electrical power system to geomagnetic storms, to assess the system’s vulnerabilities, and to develop mitigation strategies, an important example of which is work to develop sensors that can detect transformer saturation (via harmonic detection) and overheating. With this information, operators can take steps to protect costly (on the order of $10 million) and difficult-to-replace transformers. In addition, in response to the prediction of intense geomagnetic disturbances, utilities will be able to pre-position replacement equipment at key locations of high vulnerability. Such measures are critical to restoration of bulk power capabilities after disruption from a possibly crippling space weather event.
The electric power industry continues to rely on the latest developments in space weather forecasting and thus would benefit directly from implementation of the research- and applications-related programs that are recommended in this report.
1Adapted from National Research Council, Severe Space Weather Events—Understanding Societal and Economic Impacts: A Workshop Report, The National Academies Press, Washington, D.C., 2008.
precision depend fundamentally on conditions in the ionosphere that alter the paths and properties of radio waves of all frequencies, including Global Positioning System (GPS) signals.
2. Preserve the space environment, in part by pursuing “research and development of technologies and techniques … to mitigate and remove on-orbit debris, reduce hazards, and increase understanding of the current and future debris environment” and by leading “the continued development and adoption of international and industry standards to minimize debris.” Satellite drag is relevant to orbit and reentry prediction and to long-term mitigation of orbital debris. The recent inability, for example, to forecast the demise of the Upper Atmosphere Research Satellite (UARS) spacecraft underscores limitations in current capabilities for modeling and understanding the interaction of Earth-orbiting objects with the upper atmosphere. Space junk now exceeds 22,000 objects larger than a softball (Figure 7.1); collisions are expected to become more frequent (and may have propelled the UARS satellite into a less stable orbit).
2 National Research Council reports Severe Space Weather: Understanding Societal and Economic Impacts: A Workshop Report (2008) and Limiting Future Collision Risk to Spacecraft: NASA’s Meteoroid and Orbital Debris Programs: An Assessment of NASA’s Meteoroid and Orbital Debris Programs (2011), both published by The National Academies Press, Washington, D.C.
3 Committee for Space Weather, Office of the Federal Coordinator for Meteorological Services and Supporting Research, National Space Weather Program Strategic Plan, FCM-P30-2010, August 17, 2010, available at http://www.ofcm.gov/nswp-sp/fcm-p30.htm.
FIGURE 7.1 Snapshot of debris larger than 10 cm in low Earth orbit on May 1, 2001. SOURCE: Hugh Lewis, University of Southampton.
climate of the space environment. Growth in the number of space weather customers since the National Oceanic and Atmospheric Administration (NOAA) initiated a customer subscription service in 2004 (Figure 7.2) is another important indicator of the increasing U.S. need for monitoring and characterization of space weather. Moreover, the number of customers has been growing rapidly despite the deep and long-lasting solar minimum for much of the time period shown.
FIGURE 7.2 Number of unique customer subscribers routinely receiving the Space Weather Prediction Center’s space weather services electronically. SOURCE: Updated from E. Hildner, H. Singer, and T. Onsager, Space weather workshop: A catalyst for partnerships, Space Weather 9:S03006, doi:10.1029/2011SW000660, 2011.
U.S. space-based operational environment monitoring, currently based on data collected by NOAA Geostationary Operational Environmental Satellite, NOAA Polar Operational Environmental Satellite (POES), and Department of Defense (DOD) Defense Meteorological Satellites Program (DMSP) satellites, is of recognized fundamental importance to both the space weather operational and the space weather research communities. However, despite the well-documented vulnerability of essential societal, economic, and security services, space environment monitoring remains resource challenged.4 For example, key energetic particle measurements now made by the POES and DMSP spacecraft are not currently slated to continue with the next generation of low-Earth-orbiting weather satellites. To address this and related problems will require, in the survey committee’s view, a National Space Weather Program (NSWP) that is
strengthened through organizational changes and an infusion of resources. The committee also envisions a greater role for NASA in the multiagency NSWP.5
NASA research satellites such as the Advanced Composition Explorer (ACE), Solar and Heliospheric Observatory (SOHO; with the European Space Agency [ESA]), Solar Terrestrial Relations Observatory (STEREO), and Solar Dynamics Observatory (SDO), which are designed for scientific studies, have over the past decade or more provided critical measurements essential for specifying and forecasting the space environment system, including the outward propagation of eruptive solar events and solar wind conditions upstream from Earth. Although these observational capabilities have become essential for space environment operations, climatological monitoring, and research, NASA currently has neither the mandate nor the budget to sustain these measurements into the future. A growing literature has documented the need to provide a long-term strategy for monitoring in space and has elucidated the large number of space weather effects, the forecasting of which depends critically on the availability of suitable data streams.6 An example is the provision of measurements of particles and fields at the L1 Lagrange point7 (or, using technologies such as solar sails, closer to the Sun on the Sun-Earth line), which is critical for short-term forecasting of such harmful effects of space weather as damage to Earth-orbiting satellites, reduction of GPS accuracy, and potentially deleterious geomagnetically induced currents on the power grid.
The survey committee found that the existing ad hoc approach to providing space weather-related capabilities is inadequate. To help ensure a stronger approach, the committee articulates a vision for an enhanced national commitment by partnering agencies to continuous measurements of critical space environment parameters, analogous to the monitoring of the terrestrial environment being conducted by NASA in collaboration with a number of other agencies such as NOAA and the U.S. Geological Survey (USGS). Anticipating that the criticality of such a program will grow relative to other societal demands, the survey committee envisions NASA as utilizing its unique space-based capabilities as the basis for a new program that could provide sustained monitoring of key space environment observables to meet pressing national needs (see Box 7.1).
In addition to ensuring the continuity of critical measurements, robust space environment models capable of operational deployment are also necessary for the prediction and specification of conditions where observations are lacking. The survey committee anticipates that it will take decades to achieve an infrastructure for monitoring and characterizing space environment weather and climatology that is equivalent to current capabilities in the modeling and forecasting of terrestrial weather and climate; thus, it is necessary to start immediately. Achievement of critical continuity of key space environment parameters, their utilization in advanced models, and application to operations constitute a major endeavor that will require unprecedented cooperation among agencies in the areas in which each has specific expertise and unique capabilities.
5 The committee’s objectives are also consistent with the recommendations contained in the 2010 NSWP strategic plan. The plan’s recommendations for the next decade included the following: (1) establish a NSWP focal point in the Executive Office of the President; (2) ensure continuity of critical data sources; (3) strengthen the science-to-user chain; and (4) emphasize public awareness of space weather critical needs (Committee for Space Weather, Office of the Federal Coordinator for Meteorological Services and Supporting Research, National Space Weather Program Strategic Plan, FCM-P30-2010, August 17, 2010, available at http://www.ofcm.gov/nswp-sp/fcm-p30.htm).
6 For example, see National Research Council, Severe Space Weather Events—Understanding Societal and Economic Impacts: A Workshop Report, The National Academies Press, Washington, D.C., 2008, and D.N. Baker and L.J. Lanzerotti, A continuous L1 presence required for space weather, Space Weather 6:S11001, doi:10.1029/2008SW000445, 2008.
7 A description of the Lagrange points is available at http://map.gsfc.nasa.gov/mission/observatory_l2.html.
Like Earth’s near-surface environment, where climate and weather occur, the extended operational environment that encompasses space weather and space climate varies continuously on multiple time-scales in response to forcing from the Sun, the heliosphere, and the underlying atmosphere. To advance space weather and space climatology capabilities, it is essential to improve, and design appropriately, the temporal and spatial coverage of space- and ground-based measurements. A mix of assets is needed: (1) space-based measurements that provide the coverage necessary for detecting space weather hazards, some of which cannot be discovered from the ground, and (2) ground-based measurements that provide more extensive spatial coverage and a link to historical measurements. In Box 7.2 the survey committee lists the highest-priority additional data needed, an initial step toward describing a notional new program for NASA, building on the unique strengths of that agency.
Essential components of a robust space environment operational program that will complement what exists today or, in some cases, provide much needed continuity of critical capabilities, include the following:
• Monitor the variable solar-heliospheric photon, particle, and magnetic field inputs with satellites at L1 and L5.
• Monitor the geospace global and regional responses to the varying solar-heliospheric inputs with Earth-orbiting satellites, one in a high-altitude orbit (geostationary Earth orbit [GEO], for ionospheric imaging) and one in a low-altitude orbit (low Earth orbit [LEO], for detailed regional sensing and radiation belt monitoring).
• Develop, validate, test, and transition to operations physical and assimilative models of coupled solar, heliospheric, and geospace properties for specification and forecasting of the extended operational environment.
• Integrate relevant research efforts with operational activities to achieve seamless research to operations/operations to research and identify emerging needs and advances.
• Leverage the strength of NASA’s community by taking advantage of principal-investigator-led missions, hosted payloads, and other innovative approaches such as the use of microsatellites.
• Coordinate with other complementary agency missions such as those of the National Science Foundation (NSF; supporting model development and ground-based observations), DOD and NOAA (providing operational forecasts and space weather monitoring), Department of Energy (DOE; supporting modeling and monitoring), and USGS (supporting ground-based magnetic observations).
From their quasi-stable orbits at the Earth-Sun L1 libration point, which is approximately 1.5 million kilometers from Earth, instruments on NASA’s ACE and the NASA/ESA SOHO spacecraft continuously monitor the solar wind and provide solar coronagraph imaging, respectively. Information from ACE is used to provide approximately 1 hour of warning of a geomagnetic storm. To sample solar wind structures 5 days before they reach Earth and to provide global coverage of disturbances moving Earth-ward through the inner heliosphere, a spacecraft could be located at L5, the gravitationally stable location approximately 60 degrees behind Earth in its orbit as seen from the Sun. From L5, solar activity behind the limb rotating Earthward could be observed; in addition, in situ sampling of solar wind structure at a longitude distinct from
BOX 7.2 CONTINUOUS MEASUREMENTS FOR SPACE WEATHER AND CLIMATOLOGY: COMPLEMENTING AND PRESERVING OBSERVATIONS OF THE SPACE ENVIRONMENT
Solar-Heliosphere System Forcing
- Solar X-ray, extreme ultraviolet, and ultraviolet spectral irradiance and images, magnetograms
- Solar coronal-heliospheric images
- Solar wind (speed, density, temperature, ion composition)
- Interplanetary magnetic fields
- Energetic particles (solar and galactic)
Atmosphere-Ionosphere-Magnetosphere System Response and Variability
- Neutral temperature
- Electron density profile and total electron content
- Total mass density
- Neutral winds
- Electric and magnetic fields
- Ionospheric scintillation (amplitude, phase, morphology)
- Composition of major species (especially O, and O+)
- Concentration of minor species (especially radiatively active gases)
- Wave activity on all scales (gravity and planetary waves, tides)
- Energetic particles (protons, electrons, ions, neutrals)
- Auroral morphology
that accessible at L1 and rotating Earth-ward is possible. An L5 mission would build on experience using STEREO B coronagraph measurements for space weather forecasting. Finally, in addition to new space-based elements, a comprehensive and sustained program of measurements in geospace would include ground-based measurements, supported by NSF and the Air Force, as well as space-based measurements from NOAA and DOD, with NASA taking on a new monitoring role with new resources, coordinating with operational agencies. New models are also needed to satisfy the demands posed by increased user diversity.
The survey committee envisions a national commitment to a new program in solar and space physics that would provide long-term observations of the space weather environment and support the development and application of geospace models to protect critical societal infrastructure, including communication, navigation, and terrestrial weather spacecraft, through accurate forecasting of the space environment. Because NASA has a long history of conducting collaborative forefront space weather research in concert with researchers in academia, the commercial sector, and other government laboratories, the survey committee envisions an expanded role for NASA in a future space weather and climatology program. The strengths inherent in the NASA community, combined with the benefit of synergy between forefront research and space weather operations, should be brought to bear to meet U.S. needs for accurate, reliable monitoring and forecasting of space weather and climatology.
A space weather and climatology program would encompass long-term planning for critical measurements, such as the L1 solar and solar wind measurements currently acquired from ACE and SOHO. The survey committee endorses DSCOVR as a temporary interagency solution to the current lack of continuity beyond ACE, which was launched in August 1997, of L1 plasma and field measurements essential to current space weather models, while advocating the need to have a plan beyond DSCOVR for continuous and comprehensive L1 coverage. NASA is uniquely qualified to develop, build, launch, and operate spacecraft in Earth orbit and beyond, including the recommended measurements at L1 and L5 (as described in a number of white papers8). Operating such spacecraft requires use of the Deep Space Network, for example.
Below, the survey committee describes new (notional) agency-specific activities that are needed to develop the required capabilities. The program builds on critical existing capabilities, which are described in Chapter 4 for all participating agencies. Organization of the new activities is not discussed here; however, a key recommendation is to recharter the NSWP at a level of the federal government appropriate for strategic support and coordination (see Chapter 4). Availability of new resources is assumed for the notional space weather and climatology program implementation elements for each agency.
NSF would be enabled to provide real-time monitoring by means of its set of ground-based facilities.9 Ground-based facilities include radars, lidars, magnetometers, and solar observatories such as the Global Oscillation Network Group, Synoptic Optical Long-term Investigations of the Sun, and the Advanced Technology Solar Telescope. NSF would also be enabled to provide key data streams from platforms such as Iridium and to support space weather model development.
NOAA and DOD
Both NOAA and DOD would be enabled to transition models, developed as part of this vision, into operations, and they would be enabled to utilize any new data streams provided by an implementation of this vision to enhance operational services.
DOE, in cooperation with DOD, would be enabled to provide both continuity of, as well as access to, real-time data streams from space weather sensors on geosynchronous and GPS satellite platforms.
The United States would have a healthy commercial sector enabled to develop tailored space weather products for specific applications.
8 The survey committee and panels reviewed 288 mission concept white papers, which were submitted in response to an invitation to the research community. The survey’s request for information is reproduced in Appendix H, and the submissions that were received in response are listed in Appendix I and supplied on the CD that contains this report.
9 Important ground-based assets are operated by the Department of the Interior U.S. Geological Survey’s Geomagnetism Program, which provides high-quality, ground-based magnetometer data continuously from 13 observatories distributed across the United States and its territories. The program collects, transports, and can disseminate these data in near-real time, and it also has significant data-processing and data-management capacities.
An Expanded Role for NASA
Today, NASA missions such as ACE, SOHO (a collaboration with ESA), STEREO, and SDO provide space weather information without which the forecasting of solar eruptions and their heliospheric propagation would not be possible. NASA and partner agencies NSF, the Air Force Office of Scientific Research, and the Office of Naval Research support research to develop the most advanced space environment models. Many of these models can be applied to space weather forecasting, with a potentially dramatic increase in forecasting capabilities. NASA already conducts operational activities in a number of areas, including space weather forecasting for its own human and robotic missions, human spaceflight activities, and communications such as those based on the Tracking and Data Relay Satellite System. NASA also routinely provides societally relevant information obtained from models and space-based measurements, such as from the Moderate Resolution Imaging Spectroradiometer Earth-monitoring system for the atmosphere, land, and oceans.
NASA’s Heliophysics Division has developed exceptional capabilities for continuous measurement of critical space environment parameters but does not have a program that sustains the observational capabilities that are required for meeting societal needs. Consequently, it currently does not support long-term heliophysics monitoring (with continuously evolving skill) in a manner analogous to the monitoring of the terrestrial environment and surface climate that the Earth Science Mission Directorate has implemented over the past two decades.
NASA is the appropriate agency to ensure that critical data sources for space weather forecasts and operations are sustained. A suitable vehicle may be a new heliophysics space weather and climatology program whose primary focus would be on obtaining societally relevant data and observations. This program could be implemented in concert with relevant research programs underway in academia and in government laboratories, and it would leverage opportunities in the commercial sector and capitalize on the strength of NASA’s science community. Recognizing the importance of modeling to the forecasting of terrestrial weather, the program would also support model development and model applications to space weather forecasting, applying the latest advances in modeling capabilities and the most advanced data sources to drive models. The new activity could make its space weather information available to interests in the United States and beyond, and coordinate its relevant activities with DOD and NOAA operations, as well as the commercial and international space weather communities.
Below is a concept to develop the space weather and climatology (SWaC) capability outlined above. In addition, Table 7.1 lists space missions enhanced to provide needed SWaC data, and Table 7.2 presents an illustrative funding scenario for a NASA SWaC program. This new program could be started as soon as fiscal year 2014, in response to a demonstrated national need. Assuming the availability of the necessary new funding, the following steps could be taken during the first 5 years:
• Year 1
—Initiate development of an operational solar wind and solar monitoring (L1) mission.
—Initiate NASA center activities to provide real-time data streams from missions and models, to evaluate and test models, and to continue operating space-weather-relevant research missions.
—Initiate a grants program to develop and advance to operational readiness space environment specification and forecasting models.
—Initiate continued coordination with space weather forecasting organizations at DOD, NOAA, NASA, and the commercial sector for transition of relevant observations and models to operations.
TABLE 7.1 Enhanced Space Missions for Space Weather and Climatology
||Advanced warning of solar activity, background solar wind, and solar disturbances (e.g., coronal mass ejections) aimed at Earth and other locations in the solar system||
||Provides high-accuracy, ~ 30- to 45-min advanced warning of impending geomagnetic storms, validates models, and detects coronal mass ejections||
||Provides instantaneous global distribution of geospace neutral and electron densities (important, e.g., for GPS and satellite drag)||
||Provides high spatial resolution and regional detail of conditions important, e.g., for GPS and satellite drag||
NOTE: ACE, Advanced Composition Explorer; DMSP, Defense Meteorological Satellites Program; DSCOVR, Deep Space Climate Observatory; ESA, European Space Agency; GUVI, Global Ultraviolet Imager; IMAP, Interstellar Mapping and Acceleration Probe; NOAA, National Oceanic and Atmospheric Administration; SOHO, Solar and Heliospheric Observatory; STEREO, Solar Terrestrial Relations Observatory; and TIMED, Thermosphere-Ionosphere-Mesosphere Energetic and Dynamics
• Year 2
—Conduct the development and build phase of an operational L1 mission.
—Expand NASA center activities to coordinate acquisition of space weather data with other agencies (NOAA, DOD, DOE) and incorporation of data into a proposed new space weather clearinghouse, providing access to previously unavailable space weather data.
—Expand the grants program to develop and advance to operational readiness space environment specification and forecasting models.
TABLE 7.2 Illustrative Funding Scenario for a NASA Space Weather and Climatology Program (in $millions)a
a Assumes L1 launch in year 4, $500 million over 10 years, start over year 10; assumes L5 launch year 8, $575 million over 9 years, start over year 12; assumes 5-year multi-satellite Earth orbit technology development in years 5-9, launch year 10.
b Model development, data assimilation
• Year 3
—Conduct the build phase of an operational L1 mission.
—Begin development of a solar and solar wind monitoring mission for L5.
—Evaluate the effectiveness of the proposed new space weather clearinghouse in meeting multiagency operational forecast needs.
—Continue the grants program to test the operational readiness of space environment specification and forecasting models and coordinate with DOD and NOAA partners.
• Year 4
—Build, integrate, and launch an operational L1 mission.
—Continue development of a solar monitoring mission for L5.
—At a NASA center, begin to integrate and distribute operational L1 measurements.
—Continue the grants program to transition to operations the environment specification and forecasting models for use by NASA and NOAA and DOD operations.
• Year 5
—Operate the operational L1 mission, and initiate a concept study of a follow-on mission.
—Continue development of a solar monitoring mission for L5.
—Initiate a geospace monitoring mission concept study.
—At a NASA center, plan for integration of operational L5 and geospace monitoring measurements into space environment specification and forecasting models.
—Continue the grants program to facilitate a transition to operational readiness of space environment specification and forecasting models that will include new data sets as they become available.
A new plan is also needed that synthesizes and capitalizes on the strengths of the participating agencies listed above as well as opportunities in the commercial sector, such as Iridium/AMPERE. The committee sees NASA as assuming a leading role in creating a clearinghouse for coordinating the acquisition, processing, and archiving of underutilized real-time and near-real-time ground- and space-based data needed for space weather applications. For example, highly valued energetic particle measurements made by GPS and Los Alamos National Laboratory GEO satellites for specification of the radiation belts are not now routinely provided. Likewise, model development has been supported by individual agencies rather than being coordinated across relevant stakeholders.
The survey committee also foresees NASA assuming a leading role in coordinating model development through a center such as the Community Coordinated Modeling Center, which both serves as a repository for models and coordinates model development and transition to operations at NOAA, NASA, and DOD. Additional funding will be required by NOAA and DOD to support the integration of data acquired and models developed by the envisioned new NASA program in order to address the specific needs of the user communities. The illustrative scenario shown in Table 7.2 for a NASA SWaC program incorporates support for the proposed data clearinghouse and modeling effort. Combined with existing and recommended activities, a program such as the proposed SWaC effort can put the nation’s space weather forecasting and space weather and space climate monitoring program on a solid footing.
The program described above would help meet the growing space weather needs of the United States. However, given scarce resources, the survey committee recommends implementation only under circumstances that would not delay the development or the timely execution of the recommended programs for NASA that are shown in Figure 6.1.