Heliophysics Division Selected Major Accomplishments in 2007 from Alan Stern's LPSC presentation

• Successfully launched five missions (comprising ten spacecraft): Hinode (1), STEREO (2), ST-6 (1), THEMIS (5), and AIM (1).
• Selected BARREL as our Geospace Mission of Opportunity.
• Initiated the Explorer SMEX and MoO AO; Phase A down-select is planned for May 2009; three new Heliophysics/Astrophysics missions are to fly beginning in 2012.
• Continued development of the next solar physics mission - the Solar Dynamics Observatory (SDO)--toward launch in late 2008.
• Restructured the long-awaited Solar Probe mission to be a higher value, lower cost, non-nuclear mission in the medium cost category ("Solar Probe Plus").

Strategic Goal:
Understand the Sun and its effects on the Earth and the Solar System

We live in an exciting environment: the heliosphere, the exotic outer atmosphere of a star. The space beyond Earth's protective atmospheric cocoon is highly variable and far from benign. It is the one part of the cosmos accessible to direct scientific investigation, our only hands-on astrophysical laboratory. Our technological society is increasingly susceptible to space weather disturbances in this curious region. A host of interconnected physical processes, strongly influenced by solar variability, affect the health and safety of travelers in space and the habitability of alien environments. We call this new system science 'Heliophysics.' It stands for: Exploration of the Sun, its effects on Earth and the planets of the Solar System, and the space environmental conditions and their evolution.

Building on NASA's rich history of exploration of the Earth's neighborhood and distant planetary systems, we are poised to develop the quantitative knowledge needed to help assure the safety of the new generation of human and robotic explorers. The Heliophysics Program has been completely reevaluated to address the needs of the Vision for Space Exploration.

NASA's future research and exploration within its Heliophysics program aims to "explore the Sun-Earth system to understand the Sun and its effects on Earth, the solar system, and the space environmental conditions that will be experienced by explorers, and to demonstrate technologies that can improve future operational systems." We have unfolded this articulated strategic goal into the three broad science and exploration objectives:

• Open the Frontier to Space Environment Prediction: Understand the fundamental physical processes of the space environment from the Sun to Earth, to other planets, and beyond to the interstellar medium;
• Understand the Nature of Our Home in Space: Understand how human society, technological systems, and the habitability of planets are affected by solar variability and planetary magnetic fields; and,
• Safeguard the Journey of Exploration: Maximize the safety and productivity of human and robotic explorers by enabling the capability to predict the extreme and dynamic conditions in space.

These will be accomplished by studying the Sun, the heliosphere, and planetary environments as elements of a single interconnected system, one that contains dynamic space weather and evolves in response to solar, planetary and interstellar conditions. Such an understanding represents not just a grand intellectual accomplishment for our times - it also provides knowledge and predictive capabilities essential to future utilization and exploration of space. Herein, we describe current plans for NASA's research programs in this area and the guiding principles we will follow in pursuit of the forthcoming exploration challenges.

Identifying High-Priority Heliophysics Science. The intersecting ovals illustrate the intersection of three categories of science: scientific understanding that is enabled by exploration, science that transforms our knowledge, and science that informs and so enables exploration. At the intersection is the 'sweet spot' where the highest priority Heliophysics missions, represented by their acronyms, lie.

Program Elements

Scientific Theory, Modeling, Research and Analysis

Heliophysics science objectives are achieved through the efforts of a distributed scientific and technical workforce that envisions and develops the missions, and then applies the results from those missions for the benefit of society. Over the past decade and more, physics-based modeling has played an increasingly important role both in defining the missions and in interpreting the observations. It is anticipated that within three years vast arrays of datasets will be available for real-time assimilation into predictive models. Working with universities, other government facilities, and industrial labs, individual and group theory, modeling, and research and analysis efforts are identified through three competitive programs:

• The Supporting Research and Technology (SR&T) program comprises an ever-evolving suite of individual PI-proposed investigations that cover the complete range of science disciplines and techniques essential to achieve the Heliophysics Division objectives;
• The Theory Program supports larger PI-proposed team efforts that require a critical mass of expertise in order to make significant progress in understanding complex physical processes with broad importance, such as magnetic reconnection or particle acceleration; and,
• The Guest Investigator (GI) program is a synergistic component of the Heliophysics Great Observatory. The GI program enables the broadest community of researchers in universities and institutions across the country to use Great Observatory data in innovative scientific research.

Low Cost Access to Space (LCAS)

The LCAS suborbital program, whose key elements are the sounding rocket and balloon programs, is an essential component of NASA's Heliophysics research program. LCAS investigations make cutting-edge science discoveries using state-of-the-art instruments developed in a rapid turn-around environment. They fill important gaps in the prescribed program, augmenting strategic-line missions and training the next generation of space explorers. The LCAS program provides essential support for the development of new instrumentation and important hands-on training for future engineers and scientists. It also offers the high-context learning environment necessary for NASA's future explorers to gain the management skills necessary for more complex missions.

Sounding Rockets

Sounding Rockets present unique low cost platforms that provide direct access to the Earth's mesosphere and lower thermosphere (40 - 120 km), to precipitation regions of the Earth's magnetosphere, and allows researchers to reach above the Earth's atmosphere to observe the Sun. Rockets offer the ability to gather in situ data in specific geophysical targets (e.g., the aurora and noctilucent clouds), calibration underflights of orbiting missions, and the ability to recover and re-fly instrumentation.

Balloons

Balloon missions flown in the continental U.S. and Antarctica serve as "proof of concept" for new technology and future space-borne instruments (recent examples include the RHESSI hard X-ray and y-ray imaging spectrometer and the SoHO/LASCO). Science capabilities include the mapping of when and where the radiation belts drain into the Earth's atmosphere and how the Earth's global electric field can be short-circuited by Solar flares.

LWS Targeted Research & Technology

The goal of the Living With a Star (LWS) Program is to develop the scientific understanding needed for the United States to effectively address those aspects of the connected Sun-Earth system that may affect life and society. The LWS Targeted Research and Technology (TR&T) program element solicits proposals leading to a physics-based understanding of the integral system linking the Sun to the Earth both directly and via the heliosphere, magnetosphere, and ionosphere. The program's objectives can be achieved by data analysis, theory and modeling, and the development of tools and methods (e.g., software). LWS is a crosscutting program whose goals and objectives relate to NASA's Exploration Initiative, as well as NASA's Strategic Enterprises, namely (and in no priority order):

• Aeronautics - LWS characterizes those aspects of the Earth's radiation belt environment needed to design reliable electronic subsystems for use in air and space transportation systems;


• Biological and Physical Research - LWS defines the radiation environment beyond the Earth's magnetosphere to enable exploration of interplanetary space by humans;


• Earth Science - LWS improves our understanding of the effects of solar variability and disturbances on terrestrial climate change;


• Exploration Systems and Space Flight - LWS develops the knowledge needed to predict solar energetic particle events that affect the safety of humans and technology in space; and


• Space Science - LWS quantifies the physics, dynamics, and behavior of the Sun-Earth system over the 11-year solar cycle.

The LWS TR&T Science Definition Team (SDT) Report, 2003, located at URL: http://lws-trt.gsfc.nasa.gov/trt_news.htm identified particular scientific topics to be addressed using measurements by the LWS space flight missions, as well as data from other missions, and also by employing theory and modeling efforts. Among these topics are: the role of solar variability in climate and in stratospheric chemistry; ionospheric perturbations and scintillations; neutral thermosphere composition and density; geomagnetically-induced currents; energetic particles in the magnetosphere and atmosphere; and radiation associated with explosive events on the sun. The hazards to and effects on society, space-based systems, and human space flight are of particular importance to this program.

Significant progress toward quantitative understanding and predictive capability with respect to these problems will require large-scale, integrated modeling activities. Recognizing the need for activities that would be broader and more sustained than those that can be supported by a traditional NASA grants program, the TR&T Science Definition Team Report recommended that "...large modeling activities that address coupling across traditional science domains in the Sun-Earth chain specifically be included as strategic capabilities." The TR&T SDT also recommended the formation of a TR&T Steering Committee in order to update periodically the designated strategic capabilities for future NRAs. The report of this Steering Committee is available at the Web site given above.