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A Performance Assessment of NASA’s Heliophysics Program 1 Introduction and Background THE FIELD OF SOLAR AND SPACE PHYSICS Understanding the origins and manifestations of solar variability and the influence of the Sun on Earth’s atmosphere and geospace is a scientific pursuit driven both by intellectual inquiry and by societal needs. From ancient records of solar eclipses to medieval observations of sunspots and solar prominences during eclipse to Renaissance estimates of the Sun’s mass, solar physics has been a human endeavor for thousands of years, satisfying curiosity about how our nearest star works. Studies of Earth and its environment occurred in parallel, from ancient to modern times, with speculations and later key discoveries about the terrestrial magnetic field, the aurora, and meteors as atmospheric phenomena. While linkages between solar physics and geophysics were made in the nineteenth century, the physics-based field of solar-terrestrial relationships was born early in the twentieth century. At mid-century, the first space age satellites were launched and space physics changed forever our view of geospace. Today, the once-separate fields of solar physics and space physics now strive jointly to elucidate how changes in the Sun and the solar wind cause changes in the ionospheres, thermospheres, and magnetospheres surrounding Earth and other planets, as well as the heliosphere that marks the boundaries of our solar system. While changes in the total solar radiative output are small, the energetic photons (x rays and extreme ultraviolet light) and the highly variable particles and fields that escape the Sun can have profound effects on the space environment. Together, solar and space physics offers a pathway to the critical understanding of this highly coupled natural system. In addition, it addresses how the Sun’s radiation and space plasmas can affect life and technology on Earth, as well as the health of human and robotic space explorers beyond Earth. The interdisciplinary, interagency, and international enterprise of modern solar and space physics involves observing platforms in space, in the atmosphere, and on the ground that support a range of research, from fundamental, curiosity-driven investigations to predictive space weather applications. The field draws on the expertise of research physicists, instrument builders, technologists, and spacecraft engineers. In the United States, the National Aeronautics and Space Administration (NASA) and the National Science Foundation (NSF) support the field’s space- and ground-based research, while the National Oceanic and Atmospheric Administration (NOAA) applies these and other resources to deliver space weather forecasts for users in the government and private sector. Research teams often include international contributions, with foreign instruments mounted on U.S. research platforms and vice versa. By drawing on this large set of talent and resources, the research community is able to make progress in understanding the complex and highly nonlinear phenomena explored by solar and space physics.
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A Performance Assessment of NASA’s Heliophysics Program NASA’S HELIOPHYSICS DIVISION NASA’s Heliophysics Division, one of four divisions that make up NASA’s Science Mission Directorate (SMD), is responsible for managing NASA’s solar and space physics activities. In fiscal year (FY) 2008, SMD had a total budget of $4.7 billion, of which $561 million (or 12 percent) was allocated to the Heliophysics Division. The Heliophysics Division is responsible for operating 18 space-based research missions, the ongoing development of another five space-based research missions, a program of suborbital rocket- and balloon-borne research missions, and sound theoretical programs, data analysis, research, and technology development to motivate and support these missions. The Heliophysics Division manages these assets and activities through four programs: Living With a Star. Living With a Star (LWS) is an applied research program that seeks to understand how and why the Sun varies; how Earth, the solar system, and the heliosphere respond; and how this variability and response affect humanity. Through improved understanding of solar variability and its effects, LWS seeks to create a reliable, predictive capability for space weather. The Solar Dynamics Observatory (SDO) and a Radiation Belt Storm Probes (RBSP) mission, both under development, and Solar Probe Plus, under design, are the first three missions in the LWS program. Solar-Terrestrial Probes. Solar-Terrestrial Probes (STP) is a directed research program that seeks to understand the Sun-Earth connection, targeting the least understood links in the chain of plasma processes that operate from the Sun to Earth’s environment. The first STP mission, the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) mission, launched in 2001, followed by the Solar Terrestrial Relations Observatory (STEREO) and Hinode (Solar-B) missions in 2006. They will be followed by the Magnetospheric Multiscale (MMS) mission, still under development. Heliophysics Explorer Program. The Heliophysics Explorer Program funds competitively selected, principal-investigator-managed missions to provide frequent, relatively low-cost flight opportunities for world-class investigations across the entire range of fundamental solar and space physics research. The Explorer Program is NASA’s oldest space science program, with dozens of successful missions starting with Explorer 1, the first successful U.S. satellite (see Box 2.1). Recent Heliophysics Explorer missions include the Two Wide-angle Imaging Neutral-atom Spectrometers B (TWINS-B); the Aeronomy of Ice in the Mesosphere (AIM) mission; the Interstellar Boundary Explorer (IBEX); and the Coupled Ion Neutral Dynamics Investigation (CINDI), a mission of opportunity instrument flown on a DOD satellite mission. Heliophysics Research Program. The Heliophysics Research Program undertakes scientific investigations using operational space-based platforms developed under the LWS, STP, and Explorer Programs, as well as suborbital platforms managed by the Research Program, including rockets, balloons, and aircraft. The Research Program also supports the ongoing operations of Heliophysics Division spacecraft, research and analysis grants (including theory), supporting research and technology, sounding rockets, and science data archiving and computing. THE DECADAL SURVEY The solar and space physics research community and its major supporters at NASA, NOAA, and NSF have worked together over the decades to determine the science goals and direction of the field. Adopting the model of decadal surveys used successfully by the astronomy and astrophysics community since the 1960s, the National Research Council (NRC) through the Space Studies Board produced in 2003 the first 10-year strategy for solar and space physics, The Sun to the Earth—and Beyond: A Decadal Research Strategy in Solar and Space Physics1 (hereinafter the “2003 decadal survey,” or the “decadal survey”). The 2003 decadal survey was derived from the deliberations of five discipline panels: The Sun and the heliosphere, The solar wind and magnetosphere interactions, 1 National Research Council, The Sun to the Earth—and Beyond: A Decadal Research Strategy in Solar and Space Physics, The National Academies Press, Washington, D.C., 2003.
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A Performance Assessment of NASA’s Heliophysics Program TABLE 1.1 Priority Order of Programs Recommended in the 2003 Solar and Space Physics Decadal Survey Type of Program Rank Program Responsible Agency Large 1 Solar Probe NASA Moderate 1 Magnetospheric Multiscale NASA 2 Geospace Network NASA 3 Jupiter Polar Mission NASA 4 Multispacecraft Heliospheric Mission NASA 5 Geospace Electrodynamic Connections NASA 6 Suborbital Program NASA 7 Magnetospheric Constellation NASA 8 Solar Wind Sentinels NASA 9 Stereo Magnetospheric Imager NASA Small 1 Frequency-Agile Solar Radiotelescope NSF 2 Advanced Modular Incoherent Scatter Radar NSF 3 L1 Monitor NOAA 4 Solar Orbiter NASA 5 Small Instrument Distributed Ground-Based Network NSF 6 University-Class Explorer NASA Vitality 1 NASA Supporting Research and Technology NASA 2 National Space Weather Program NSF-led/multiagency 3 Couple Complexity NASA/NSF 4 Solar and Space Physics Information System Multiagency 5 Guest Investigator Program NASA/NSF 6 SEC Theory and LWS Data, Analysis, Theory and Modeling NASA/NSF 7 Virtual Sun Multiagency Atmosphere-ionosphere-magnetosphere interactions, Theory, modeling, and data exploration, and Education and society. For the decade 2003 to 2013, the survey identified five science challenges that would advance understanding of solar and space physics: Challenge 1. Understanding the structure and dynamics of the Sun’s interior, the generation of solar magnetic fields, the origin of the solar cycle, the causes of solar activity, and the structure and dynamics of the corona. Challenge 2. Understanding heliospheric structure, the distribution of magnetic fields and matter throughout the solar system, and the interaction of the solar atmosphere with the local interstellar medium. Challenge 3. Understanding the space environments of Earth and other solar system bodies and their dynamical response to external and internal influences. Challenge 4. Understanding the basic physical principles manifest in processes observed in solar and space plasmas. Challenge 5. Developing a near-real-time predictive capability for understanding and quantifying the impact on human activities of dynamical processes at the Sun, in the interplanetary medium, and in Earth’s magnetosphere and ionosphere. To address these challenges, the decadal survey developed an integrated strategy to advance the relevant physical theories, incorporate those theories in models that describe a system of interactions between the Sun and
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A Performance Assessment of NASA’s Heliophysics Program the space environment, obtain data on the system, and analyze and test the adequacy of the theories and models. This integrated strategy was embodied by the core recommendation in the second chapter of the decadal survey—a prioritized list of flight missions and theory and modeling programs. NASA’s responsibilities under the integrated strategy included launching three space-based research missions (Solar-B, STEREO, and the SDO), launching or starting development of 10 new space-based research missions during the upcoming decade (MMS, Geospace Network, Global Electrodynamic Connection, Jupiter Polar Mission, Solar Orbiter, Multi-Heliospheric Probes, Stereo Magnetospheric Imager, Magnetospheric Constellation, Solar Probe, and Solar Wind Sentinels), and continuing investments in small space-based (Explorer Program) and suborbital research missions, mission operations and data analysis, and supporting research and technology. The Integrated Research Strategy categorized these activities by cost as large, moderate, small, and vitality programs and prioritized activities within and across each category (see Table 1.1). The decadal survey generated a budget based on NASA’s cost estimates for these activities that was phased to maximize opportunities for concurrent observations of the same solar and space physics phenomena by multiple spacecraft. These coordinated investigations were a key aspect of the decadal survey’s Integrated Research Strategy, later termed the “Heliophysics Great Observatory” by NASA (see Box 1.1). The decadal survey also considered non-mission-specific initiatives that foster the development of a robust program in solar and space physics. Chapters 3 through 7 of the decadal survey set forth recommendations devoted, respectively, to the need for technology development, the advantages that accrue through collaborations and cooperation with other disciplines, the effects of the space environment on technology and society, the need for education and public outreach for solar and space physics, and steps that could strengthen and enhance the program. THE MIDTERM ASSESSMENT In the NASA Authorization Act of 2005, the Congress directed NASA, through the National Academy of Sciences, to review and assess each division in the Science Mission Directorate at 5-year intervals. In 2007, the NRC created the Committee on Heliophysics Performance Assessment to study the alignment of NASA’s Heliophysics Division program with the decadal survey. The committee was specifically tasked with answering three questions, which are addressed in Chapters 2 and 3 of this report: How well does NASA’s current program address the strategies, goals, and priorities outlined in the decadal survey and other relevant NRC reports? See Section 2.1. The committee has interpreted NASA’s “current program” to mean its recommended Heliophysics Roadmap, issued in 2005.2 What progress has been made toward realizing these strategies, goals, and priorities? See Sections 2.2 to 2.7. Can any actions be taken to optimize the science value of the program in the context of current and forecasted resources available to it? See Chapter 3. The committee was directed not to alter the scientific priorities or mission recommendations provided in the 2003 decadal survey but was asked to provide guidance (see Chapter 3) for implementing the recommended mission portfolio in preparation for the next decadal survey. The decadal survey is a positive and welcome development for the field, and this midterm assessment reinforces its recommendations. ACCOMPLISHMENTS SINCE THE DECADAL SURVEY Since the release of the decadal survey, NASA’s Heliophysics Division and the solar and space physics community have advanced on all of the major fronts of the research enterprise, including solar, ionospheric-thermospheric-mesospheric, magnetospheric, and heliospheric physics. Four examples of many notable accomplishments over the past 5 years are as follows: 2 NASA, The New Science of the Sun-Solar System Connection: Recommended Roadmap for Science and Technology 2005-2035, Washington, D.C., 2005.
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A Performance Assessment of NASA’s Heliophysics Program BOX 1.1 NASA’s Heliophysics Great Observatory and the Decadal Survey’s Integrated Research Strategy The investigation of solar system plasmas as coupled nonlinear systems requires synergy between observational and theoretical initiatives and between basic research and targeted research programs. NASA recognized this in establishing a fleet of 12 missions—consisting of the Advanced Composition Explorer (ACE), Solar and Heliospheric Observatory (SOHO), and Wind in L1 orbit; Cluster, Transition Region and Coronal Explorer (TRACE), Ramaty High-Energy Solar Spectroscopic Imager (RHESSI), Geotail, Fast Auroral Snapshot Explorer (FAST), Polar, and Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) in Earth orbit; and Ulysses and the Voyager probes—that NASA’s Heliophysics Division would later call its Heliophysics Great Observatory. SOHO, TRACE, and RHESSI observe the variable outputs of the Sun; ACE and Wind provide advance information on the disturbances traveling to Earth; Cluster, Geotail, FAST, POLAR, and TIMED observe the resulting space weather responses in the geospace environment; and Ulysses and Voyager measure responses in the heliosphere. The Heliophysics Great Observatory enabled the coordinated investigation of space plasmas as complex coupled systems driven from the Sun to Earth and into the heliosphere, as demonstrated by the observation and analysis of the famous “Halloween” solar storms of 2003. The decadal survey clearly recognized the mission synergies and balance that underpin the Heliophysics Great Observatory approach: mission selections and priorities in the Integrated Research Strategy were chosen in order to most efficiently maintain and augment such a research approach. The decadal survey anticipated a midterm period where Solar-B, Solar Terrestrial Relations Observatory (STEREO), and Solar Dynamics Observatory (SDO) would be providing more detailed information on the propagation of solar disturbances to Earth, while the Magnetospheric Multiscale (MMS) mission, the Geospace Network, and the Geospace Electrodynamic Connections (GEC) mission would be providing the information needed to understand how the disturbances were processed within the geospace system. Throughout this period the Explorer Program was expected to play a pivotal role in addressing new inquiries and strategic initiatives that would emerge during the conduct of the program. A revitalized sounding rocket program would also continue to provide unique capabilities associated with access to critical regions and diagnosis of small-scale features. However, as of this writing, the only two strategic missions to have been successfully implemented are Solar-B (Hinode) and STEREO. SDO and MMS are in development, and the Geospace Network and GEC have not received starts. Only one of the 10 large and moderate missions called for in the decadal survey (see Table 1.1), Jupiter Polar Mission, will be launched by 2013, the end of the 10-year period covered by the strategy. Thus, one of the foremost findings of this report is that the status of the Integrated Research Strategy is in jeopardy and that the loss of synergistic capabilities in space will seriously impede progress in the Heliophysics Division. Hinode, SOHO, and STEREO Missions Identify Origins of the Solar Wind. The solar atmosphere consists of closed magnetic loops anchored to the solar surface at both ends, and also of open flux tubes extending from the Sun into space. Early models proposed that the solar wind was heated and accelerated strictly within the regions of open magnetic field. An unprecedented complement of spacecraft instrumentation, including NASA’s SOHO and its STEREO and the Japanese Hinode mission, has recently revealed that some jets originate from the interfaces between the open and closed magnetic fields, driven by a process called magnetic reconnection (see Figure 1.1). CINDI Mission Maps Baseline for Earth’s Equatorial Ionosphere. CINDI is a NASA mission of opportunity flown on the DOD’s Communication/Navigation Outage Forecast System (C/NOFS) satellite, which launched in 2008. The CINDI instruments measure neutral wind and ion drift vectors along with total ion density, composition, and temperature. Initial data were taken during a time of extremely low solar activity when most of the atmosphere lay below the satellite’s altitude. Measurements made by CINDI during that time have revealed the daily expansion
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A Performance Assessment of NASA’s Heliophysics Program FIGURE 1.1 Coronal jets, a key contributor to the solar wind, observed from different spacecraft. The bottom image, from the X-ray Telescope (XRT) on Hinode, shows jets as small triangular features populating the most northerly latitudes of the Sun. In this region, formerly believed to consist of only open field, reconnection between open and closed fields produces jets in numbers far greater than and with outflow speeds far greater than previously suspected. The two top images show one large jet produced by magnetic reconnection observed from two different perspectives. The right top image is from the STEREO A spacecraft orbiting the Sun ahead of Earth and the left top image is from the STEREO B spacecraft orbiting the Sun behind Earth. These images of coronal plasma jetting upward reveal its twisted structure as only multiple views truly can. SOURCE: Courtesy of Jonathan Cirtain, NASA Marshall Space Flight Center. and contraction of the ionosphere, using the height at which the densities of the constituent species O+ and H+ were equal as a key ionospheric marker. This information, together with measurements of the ion temperature, provides a baseline from which future variations in solar activity can be recorded (see Figure 1.2.). THEMIS Mission Determines Auroral Brightening Sequence (Magnetosphere). In 2008, NASA’s Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission, part of NASA’s Heliospheric Explorer Program, determined the sequencing of magnetic substorms in Earth’s magnetotail that are responsible for sudden brightening and expansion of Earth’s aurora. The five-spacecraft mission, in combination with ground-based observations, found that magnetic reconnection in the near-tail initiates the substorm and is followed by tailward ejection of plasma and rapid auroral brightening and poleward expansion (see Figure 1.3). Voyager Missions Cross the Termination Shock and Enter Heliosheath (Heliosphere). In 2004 and 2007, respectively, NASA’s Voyager 1 and Voyager 2 missions crossed the heliospheric termination shock, where the
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A Performance Assessment of NASA’s Heliophysics Program FIGURE 1.2 Spatial distribution of the oxygen/hydrogen ion transition height observed by CINDI during May and June 2008, showing the daily expansion and contraction of the ionosphere. SOURCE: Courtesy of Rod Heelis, William B. Hanson Center for Space Sciences, University of Texas at Dallas. FIGURE 1.3 Artist’s concept showing the explosive release of energy generated by magnetic reconnection processes, which are responsible for sudden increases in the brightness and movement of the northern lights. SOURCE: Courtesy of NASA.
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A Performance Assessment of NASA’s Heliophysics Program FIGURE 1.4 A schematic of the position of the Voyager 1 and 2 spacecraft (V1 and V2) as they leave our heliosphere, relative to the termination shock, heliosheath, heliopause, and bow shock. SOURCE: Courtesy of Jack R. Jokipii, University of Arizona. solar wind begins interacting with the interstellar medium. The Voyager spacecraft discovered the termination shock’s location at 84 (Voyager 2) and 94 (Voyager 1) astronomical units (AU) from the Sun and ascertained that the termination shock’s overall shape is blunt and that it is not a source of anomalous cosmic rays, as had been expected. Instead, the Voyagers identified a new, lower-energy population of particles at the termination shock. Beyond the termination shock, the Voyagers started providing the first data ever on the largest structure in our solar system, the heliosheath, where the solar wind slows to the speed of the interstellar medium. NASA’s IBEX mission, launched in 2008, will start providing remote imaging of the termination shock and heliosheath. In coming years, the Voyagers will cross the Sun’s hypothesized bow shock and enter interstellar space proper (see Figure 1.4). BUDGET CHANGES SINCE THE DECADAL SURVEY A number of budget-related factors, some within NASA’s control and some outside it, have altered NASA’s implementation of the decadal survey’s recommendations. When assessing the progress of NASA’s Heliophysics Division, it is important to understand how the costs and budgets of NASA’s solar and space physics programs have changed over the 5 years since the decadal survey was prepared.
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A Performance Assessment of NASA’s Heliophysics Program FIGURE 1.5 Recommended budget phasing of NASA programs from the solar and space physics decadal survey. SOURCE: National Research Council, The Sun to the Earth—and Beyond: A Decadal Research Strategy in Solar and Space Physics, The National Academies Press, Washington, D.C., 2003, p. 8. Figure 1.5 is the recommended 2003-2013 budget for priority NASA programs in the decadal survey, based on a level Heliophysics Division budget of approximately $650 million per year.3 The decadal survey anticipated that by early FY 2009, NASA would have made progress as follows: Development complete for Solar-B, STEREO, and SDO. Development of MMS nearly complete. Development of the Geospace Network largely complete. Development of GEC and the Jupiter Polar Mission more than half complete. Development of Solar Orbiter, Multispacecraft Heliospheric Mission (MHM), and Stereo Magnetospheric Imager (SMI) well under way. Development of Magnetospheric Constellation (MagCon) just under way. Unfortunately, the actual program and budget have not matched the anticipated program or budget. Figure 1.6 is the actual 2003-2008 budget and projected 2009-2013 budget for the same NASA Heliophysics Division programs. Over the past 6 years, a number of budgetary and cost factors, both within and outside NASA’s control, have affected implementation of the Integrated Research Strategy recommended by the decadal survey. 3 National Research Council, The Sun to the Earth—and Beyond: A Decadal Research Strategy in Solar and Space Physics, The National Academies Press, Washington, D.C., 2003, p. 8.
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A Performance Assessment of NASA’s Heliophysics Program FIGURE 1.6 NASA Heliophysics Division actual and projected budget implementation. SOURCE: Data courtesy of NASA. Cost Growth in Missions Under Development at the Time of the Survey The 2003 decadal survey endorsed completion of three major NASA missions under development in 2003: Solar-B, STEREO, and SDO. The budget totals for completing Solar-B and STEREO are close to the budgets in the decadal survey. However, the decadal survey assumed that SDO could be completed in 2008 for an additional $315 million. In reality, SDO will require at least $700 million more before its launch in late 2009 or in 2010. Cost Growth in Development of Missions Recommended in the Survey The first new NASA mission recommended by the decadal survey—MMS—and an RBSP mission have experienced significant cost growth. The decadal survey allocated $350 million for MMS development and characterized the level of technical concern associated with its completion as “low.” The latest estimate for MMS is $990 million. Factors leading to MMS’s cost escalation are described in detail in Section 2.2 of Chapter 2. Decadal survey costs for the Geospace Network, a mission to investigate energy transfer within and between Earth’s ionosphere and radiation belts, were estimated at $400 million. NASA has yet to start development of the mission as originally intended. Rather, an RBSP mission, which by itself does not constitute a complete Geospace Network mission, has been started with an expected cost of more than $600 million. Factors leading to RBSP’s cost escalation are described in detail in Section 2.2 of Chapter 2. Underestimation of Decadal Survey Costs for Mission Operations and Data Analysis The decadal survey assumed an annual budget of $60 million for Heliophysics Division mission operations and data analysis (MO&DA). Actual costs from FY 2004 to FY 2008 have ranged between approximately $80 million and $120 million and are projected to remain between $70 million and $80 million from FY 2009 to FY 2013.
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A Performance Assessment of NASA’s Heliophysics Program FIGURE 1.7 NASA Heliophysics Division budgets. NOTE: This figure (but not Figures 1.5 and 1.6) has not been normalized for year-to-year changes in full-cost accounting methods and includes funding for NASA’s Astrophysics Explorer missions. SOURCE: Data courtesy of NASA. Budgets for NASA’s Heliophysics Division Did Not Meet Projections Figure 1.7 shows the actual budget for NASA’s Heliophysics Division from FY 2002 to FY 2008, as well as the 5-year projections from the President’s FY 2004, FY 2005, and FY 2009 budgets. At the time of the decadal survey, the 5-year profile in the President’s FY 2004 budget projected growth from about $800 million in FY 2004 to about $1,250 million in FY 2008. The actual appropriated budget for NASA’s Heliophysics Division varied between approximately $710 million and $840 million over the same years, including about $250 million per year in Deep Space Network (DSN) costs that were transferred out of the Heliophysics Division budget starting in FY 2009. Approximately $1.3 billion of the projected growth in the Heliophysics Division budget was eliminated in the President’s FY 2005 budget to help fund new human space exploration programs under the Vision for Space Exploration. The decadal survey did not take the FY 2004 budget projection on faith and instead constructed priorities based on a budget of approximately $650 million per year for FY 2006 and beyond. This budget level included responsibility for funding one decadal survey priority, the Jupiter Polar Mission (JPM), which is now part of NASA’s Planetary Science Division. After backing out DSN costs, in terms of program content, actual appropriations have been quite close to the $650 million assumed in the survey. Reductions in Budgets for Regular Flight Opportunities The decadal survey assumed an annual budget of $125 million for the Heliophysics Explorer Program to sustain a regular series of opportunities for competitively selected mission investigations. As Figure 1.8 shows, the annual budget for Heliophysics Explorers ranged between approximately $50 million and $120 million from FY 2004 to FY 2008. The FY 2008 funding of $50 million is projected to grow to $90 million by FY 2013, including both selected Heliophysics Explorer missions and half of the future Explorer budget for upcoming Explorer competition selections. The Solar-Terrestrial Probes budget has undergone similar large swings in funding. As shown in Figure 1.9, the
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A Performance Assessment of NASA’s Heliophysics Program FIGURE 1.8 Heliophysics Explorer Program actual and projected budget, assuming that heliophysics proposals win half of future Explorer Program funding. SOURCE: Data courtesy of NASA. FIGURE 1.9 Solar-Terrestrial Probes actual and projected budget. SOURCE: Data courtesy of NASA.
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A Performance Assessment of NASA’s Heliophysics Program FIGURE 1.10 NASA Heliophysics Division spacecraft mission launch rate. NOTE: In this figure, the 2010 mission is SDO and the 2011 mission is RBSP. SOURCE: Data courtesy of NASA. STP budget rose to approximately $140 million in FY 2004 and then dropped to approximately $70 million in FY 2008. The STP budget is projected to grow to between $160 million and $170 million by FY 2011 to FY 2013. These swings in funding have reduced the frequency of Explorer, STP, and overall Heliophysics Division spacecraft missions, decreasing opportunities for scientific investigations. Figure 1.10 shows the launch rate for NASA Heliophysics Division spacecraft missions, which peaked at two to four missions per year in 2006 to 2008 but is projected to decrease to between zero and one mission per year in the 2009 to 2013 time frame. (Under an ongoing competition whose outcome is not available at the time of this report, NASA may select one or more Heliophysics Small Explorer missions in early 2009 that may launch before 2013.) OTHER PROGRAM CHANGES SINCE THE DECADAL SURVEY In addition to cost growth, underestimated costs, and budget changes, changes in mission priorities, schedules, and launch vehicles have altered NASA’s implementation of the decadal survey’s recommendations and may continue to do so in the future. Reordering of the Mission Sequence Recommended in the Decadal Survey In the President’s FY 2009 budget, NASA proposed advancing the Solar Probe mission ahead of other missions in the 2003 decadal survey’s recommended mission sequence. The decadal survey recommended starting Solar Probe, the only mission priority in the large-program category, only after additional funding for NASA’s
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A Performance Assessment of NASA’s Heliophysics Program Heliophysics Division materialized.4 NASA has compromised the survey’s mission sequence by advancing Solar Probe ahead of the fourth, MHM, the fifth, GEC, and the seventh, MagCon, moderate-mission priorities identified in the survey, none of which has begun development. NASA has also begun an apparent reformulation of MHM and Solar Wind Sentinels (SWS), the eighth-ranked moderate mission priority in the survey, ahead of a clear execution plan for MHM, GEC, and MagCon. Schedule Delays and Deferments for Missions Recommended in the Survey Nearly all of the moderate NASA space missions recommended in the decadal survey have seen multiyear delays (MMS from 2010 to 2014) or have been indefinitely deferred (Geospace Network, MHM, GEC, MagCon, and SMI). These delays and deferrals reduce opportunities for concurrent and synergistic observations, seriously compromising the decadal survey’s integrated strategy, especially in terms of the Heliophysics Great Observatory. Reduction in Range of Available Launch Vehicles Historically, the Heliophysics Division has relied heavily on small and medium-sized spacecraft launched on small- (Pegasus) and medium-class (Delta II) launch vehicles. The decadal survey’s moderate spacecraft mission recommendations assumed availability of a medium-class launch capability. In the past, Medium Explorer (MIDEX) missions in the Explorer Program, such as the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) and THEMIS, have also used medium-class launches. With the migration of the Air Force’s Global Positioning System spacecraft from the Delta II launch vehicle to the Evolved Expendable Launch Vehicles, the long-term outlook for the Delta II launch vehicle line is in doubt, and it could be retired as early as 2012. Unless a means of extending its life or replacing the Delta II line at reasonable cost is found, the Heliophysics Division will have no capability for launching medium-sized spacecraft. This will either force a migration of these missions to larger launch vehicles, with associated increases in launch and mission costs, or force a dramatic change in the implementation plan for the currently recommended program. Division Name Change Since the decadal survey, there has been a change in the title of the division in NASA’s Science Mission Directorate responsible for carrying out the survey, from the Solar and Space Physics Division to the Heliophysics Division. Both the decadal survey and the work of the Heliophysics Division address the full breadth of the solar and space physics field, including solar, magnetospheric, ionospheric, thermospheric, mesospheric, and heliospheric physics. However, as noted by NASA’s Geospace Mission Operations Working Group, the wording “Heliophysics Division” can be misconstrued to mean a more limited emphasis on the study of solar physics. The risk is that the field’s actual scope and the integrated nature of much of the field’s current research will not be well represented to the world at large beyond NASA. CHALLENGES TO FUTURE PROGRESS Over the past 5 years, NASA investments in the missions that would later comprise the Heliophysics Great Observatory and other research activities prior to the decadal survey continue to pay high dividends, enabling breakthrough discoveries that result in a better and deeper understanding of how various coupled, nonlinear systems drive changes in space plasmas from the Sun to Earth and into the heliosphere. The decadal survey built on this model of research and recommended the Integrated Research Strategy, which sought to extend and augment the Heliophysics Great Observatory approach as well as to enhance NASA’s other solar and space physics research 4 National Research Council, The Sun to the Earth—and Beyond: A Decadal Research Strategy in Solar and Space Physics, The National Academies Press, Washington, D.C., 2003, p. 8.
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A Performance Assessment of NASA’s Heliophysics Program and supporting activities. But as Chapter 1 has shown, very little of the recommended NASA priorities from the decadal survey will be realized during the period covered by the survey. Mission cost growth, reordering of survey mission priorities, and unrealized budget assumptions have delayed or deferred nearly all of the NASA missions recommended in the survey. Some of these factors were largely outside NASA’s control, but as the assessments in Chapter 2 detail, many were driven by subsequent NASA decisions about mission science content, mission size, and mission sequence. Overcoming these challenges, as well as other key issues like launch vehicle availability, will be critical if NASA is to realize more of the decadal survey’s priorities over the next 5 years and to succeed in its solar and space physics research enterprise over the long term. Chapter 3 provides recommendations about how NASA can better fulfill the 2003 decadal survey and improve future decadal surveys in solar and space physics.