Solar and Space Physics and Its Role in Space Exploration (2004)

The following one-page summaries describe key elements of the NASA Sun-Earth Connection program, including planned and recommended future Living With a Star and Solar Terrestrial Probe mission lines, the Explorer program, and critical supporting activities. The summaries utilize program information from NASA and the committee’s assessment of the relevance of the projects and activities to the NASA exploration vision.

Ongoing line of scientifically focused principal-investigator-led missions

The Explorer program has, since the beginning of the space age, been the bedrock of space-based solar and space physics research through a series of small- and medium-sized missions. Present-day Explorers like SAMPEX, ACE, TRACE, FAST, IMAGE, and RHESSI have enabled ground-breaking research on space plasma phenomena found in the Sun and interplanetary space as well as in Earth’s own magnetosphere and upper atmosphere. Explorer missions recently selected for flight will investigate the aeronomy of ice in the mesosphere and the onset mechanisms of magnetospheric substorms. Potential future Explorer missions may perform remote sensing of planetary magnetospheres, heliospheric boundaries, and termination shocks. The Explorer program’s strength lies in its ability to respond rapidly to new concepts and developments in science as well as in the program’s synergistic relationship with ongoing strategic missions. For example, ACE and IMAGE contributed solar-wind data and magnetospheric imaging, respectively, to the ISTP missions Polar and Cluster. Similarly, spectrally selective imaging by TRACE and RHESSI supplemented the comprehensive measurements of the USTP SOHO mission. Run according to NASA’s “faster, better, cheaper” management principles, Explorer missions are relatively low-budget and require little technology development, so they have the ability to adapt to the ever-changing, immediate needs of the space science community.

Explorer missions are currently providing:

• Data on the triggering of coronal mass ejections (TRACE) and the source of solar energetic particles (RHESSI),

• Early warning of the arrival of interplanetary disturbances (ACE),

• Global imaging of space weather effects in the magnetosphere (IMAGE), and

• Monitoring of Earth’s radiation belts (SAMPEX).

By nature of their quick and cost-effective design and operation, Explorer missions are well suited to meet the needs of whatever scientific questions or space weather issues may arise in conjunction with exploration. Explorer missions can work in tandem with other space science missions as well as with strategic exploration missions to fill gaps in space physics or astronomical knowledge and thereby pave the way for future discovery.

Phase C, hardware fabrication; launch October 2006

THEMIS answers fundamental outstanding questions regarding the magnetospheric substorm instability, a dominant mechanism of transport and explosive release of solar wind energy within geospace. THEMIS will elucidate which magnetotail process is responsible for substorm onset at the region where substorm auroras map (~10 R_e): (1) a local disruption of the plasma sheet current or (2) that current’s interaction with the rapid influx of plasma emanating from lobe flux annihilation at ~25 R_e. Correlative observations from long-baseline (2 to 25 R_e) probe conjunctions will delineate the causal relationship and macroscale interaction between the substorm components. THEMIS’s five identical probes will measure particles and fields on orbits that optimize tail-aligned conjunctions over North America. Ground observatories time auroral breakup onset. Three inner probes at ~10 R_e monitor current disruption onset, while two outer probes, at 20 and 30 R_e, respectively, remotely monitor plasma acceleration due to lobe flux dissipation. In addition to addressing its primary objective, THEMIS will answer critical questions in radiation belt physics and solar wind-magnetosphere energy coupling. THEMIS’s probes use flight-proven instruments and subsystems, yet demonstrate spacecraft design strategies ideal for constellation class missions. THEMIS is complementary to MMS and a science and a technology pathfinder for future STP missions.

• Establish when and where substorms start,

• Determine how the individual substorm components interact macroscopically,

• Determine how substorms power the aurora, and

• Identify how the substorm instability couples dynamically to local current disruption modes.

THEMIS addresses two of NASA’s primary SEC themes: How does our planet respond to solar variations? and, How does solar variability affect society? THEMIS will play a key role in understanding Earth’s space environment and a prerequisite to understanding space weather. Specifically, the coupling of energy from the magnetosphere to the ionosphere is dominated by substorms, and if the time and place of substorm initiation can be predicted accurately, then better predictions of the resulting effects on the upper atmosphere and ionosphere can be made.

THEMIS is a macroscale mission, with objectives and orbits complementary to those of the micro- and mesoscale mission MMS.

JAXA (Japan)/PPARC (UK)/NASA, instrumentation built, in system integration stage, launch 2006

NASA will provide the focal plane package (FPP) for the optical telescope as well as components of the X-ray telescope and Extreme Ultraviolet Imaging Spectrometer. NASA has selected three U.S. teams to participate in the development of these scientific instruments.

Solar-B will provide a new comprehensive view of the dynamic solar atmosphere and enable a unique and timely interaction between theory and observations. The Solar-B international collaboration is based on the very successful Japan/UK/U.S. Yohkoh mission that observed x-ray and gamma-ray solar phenomena. Using a combination of optical, EUV, and x-ray instrumentation, Solar-B will study the Sun’s outer atmosphere, surface, and near-surface layers as a magnetically linked system. This approach will shed light on the way that the Sun’s magnetic field modulates solar luminosity and generates the million-degree corona and supersonic solar wind, and also how the magnetic field contributes to the explosive release of solar flares and coronal mass ejections into the solar system. Solar-B will provide the first space-based observations of the Sun’s vector magnetic fields, gathering continuous high-spatial- and high-temporal-resolution measurements over active-region scale fields of view. Such observations help determine the extent to which free energy stored in sheared or twisted (i.e., non-potential) magnetic fields heats the corona and powers solar flares and coronal mass ejections.

Solar-B will seek to understand:

• The creation and destruction of the Sun’s magnetic field,

• Solar magnetic explosions,

• The generation of EUV and x-ray radiation in the Sun, and

• Modulation of the Sun’s luminosity.

Solar activity is the primary driver of the space weather. By quantitatively understanding the solar physics that causes processes such as flares and CMEs (i.e., the relationship between the release of magnetic energy and the magnitude of the resulting flare), scientists will be able to more accurately predict major solar eruptions that significantly affect space weather. Knowledge of the three-dimensional magnetic structure of the eruptive material is also important for predicting its propagation through and interaction with the solar wind and its time of arrival at an interplanetary spacecraft. Solar-B will provide EUV and x-ray observations of unprecedented spatial resolution, wavelength coverage, and temporal continuity that will reveal the mechanisms of energetic particle acceleration in solar flares.

NASA STP, Phase C/D, launch 2006

STEREO is designed to develop an understanding of the fundamental nature and origin of coronal mass ejections—the most energetic eruptions on the Sun and the primary cause of major geomagnetic storms. Using remote sensing instruments, STEREO will image the three-dimensional evolution of CMEs from birth at the Sun’s surface through the corona and interplanetary medium. Using in situ instruments, STEREO will measure properties of particles and vector magnetic fields of both CMEs and the ambient solar wind at 1 AU. These observations will occur at two locations in solar orbit: one spacecraft in orbit in front of Earth and one behind. The resulting stereoscopic vision will help to construct a global picture of the Sun and its influences on the space environment.

STEREO will attempt to:

• Understand the causes and mechanisms triggering coronal mass ejections,

• Characterize the propagation of coronal mass ejections through the heliosphere,

• Discover the mechanisms and sites of energetic particle acceleration in the low corona and the interplanetary medium, and

• Develop a three-dimensional, time-dependent model of the magnetic topology, temperature, density, and velocity structure of the ambient solar wind.

By revealing the physics behind the mechanisms that cause coronal mass ejections as well as the trajectories and properties of the ejections as they propagate through the heliosphere, STEREO will be able to generate unique alerts for Earth-directed events as well as alerts for events directed at the Moon, Mars, or an interplanetary spacecraft. STEREO’s study of energetic particle acceleration will enable predictions of the occurrence and intensity of particle events, necessary ingredients for evaluating their potential hazard to astronauts. A comprehensive model of the ambient solar wind will also enable better understanding of its short- and long-term impacts on Earth, nearby planets, and exploration initiative spacecraft. True predictive power necessitates an understanding of both sporadic solar events and the ambient solar wind—and especially their interaction—which STEREO is designed to investigate.

NASA LWS, Phase B, launch 2008

SDO is the first mission in NASA’s Living With a Star program and is being designed to understand, driving toward a predictive capability, the solar variations that influence life on Earth and humanity’s technological systems. From geosynchronous orbit, SDO will study how the Sun’s magnetic field is generated and structured and how this stored magnetic energy is converted and released into the heliosphere and geospace in the form of solar wind, energetic particles, and variations in the solar irradiance.

SDO will study:

• The mechanisms driving the quasi-periodic, 11-year cycle of solar activity;

• The synthesis, concentration, and dispersion across the solar surface of the active region magnetic flux;

• The relation between magnetic reconnection on small scales and the reorganization of large-scale field topology as well as magnetic reconnection’s significance in heating the corona and accelerating the solar wind;

• The origins of the observed variations in the Sun’s EUV spectral irradiance and their relation to magnetic activity cycles;

• The magnetic field configurations that lead to coronal mass ejections, filament eruptions, and flares that produce energetic particles and radiation;

• The degree to which the structure and dynamics of the solar wind near Earth can be determined from the magnetic field configuration and atmospheric structure near the solar surface; and

• The possibility of making accurate and reliable forecasts of space weather and climate.

Because solar activity is the primary driver of a range of potentially hazardous space weather effects, SDO’s observations of the magnetic causes and dynamic repercussions of events such as coronal mass ejections and flares will, in conjunction with realistic models, greatly improve the accuracy of space weather forecasts. In particular, it will provide solar surface vector magnetic field observations that, in combination with coronal plasma observations, will guide interpretation of the magnetic reconnection processes believed to be intrinsic to solar activity. SDO helioseismology observations can be used to monitor the evolution of active regions on the unobservable opposite face of the Sun, providing additional warnings of potential solar activity. Since space weather involves the interaction between sporadic ejecta from the Sun and the ambient solar wind through which the ejecta propagate, true predictive power necessitates an understanding of both. SDO will provide crucial information about the source of the ambient solar wind which can be combined with observations of dynamic solar processes to gain insight into the global heliospheric environment experienced by exploring astronauts and spacecraft. The EUV irradiance monitor on board SDO will also improve our ability to understand the effect of the Sun’s irradiance on Earth’s and Mars’s upper atmospheres, critical for maintaining good communications.

NASA STP, Phase A, launch 2010

The overall objective of the MMS mission is to obtain a detailed understanding of the physics of the magnetic reconnection process and the associated phenomena of plasma turbulence and charged particle acceleration. MMS will employ four identically instrumented spacecraft orbiting in tetrahedral formation to conduct definitive investigations of reconnection in key boundary regions of Earth’s magnetosphere. Reconnection is fundamental to our understanding of astrophysical and solar system plasma phenomena such as coronal mass ejections, solar flares, magnetospheric substorms, and the acceleration of relativistic particles throughout the cosmos. It is only in Earth’s magnetosphere, however, that reconnection is readily accessible for sustained study through the in situ measurement of plasma properties and the electric and magnetic fields that govern its behavior. MMS will acquire high-resolution measurements of Earth’s magnetosphere by its cluster of spacecraft whose separations can be varied from 10 km to a few thousands of kilometers.

MMS will:

• Probe the crucial microscopic physics involved in reconnection;

• Determine the three-dimensional geometry of the plasma, field, and current structure associated with it; and

• Relate the microscale processes to phenomena occurring at larger scales in adjacent regions.

Safe interplanetary travel will ultimately depend on the ability to predict the planetary and heliospheric environments through which the exploration spacecraft will have to pass. Magnetic reconnection is considered to be the main driver of the most energetic phenomena within the solar system plasma environment (e.g., solar flares, coronal mass ejections, and magnetic storms), and the ability to predict these phenomena to ensure the safety of astronauts and interplanetary spacecraft hinges on acquiring sound scientific understanding of magnetic reconnection, which MMS is designed to obtain.

NASA LWS, Pre-Phase A, GS-ITSP Probes launch 2010, GS-RBSP Probes launch 2012

Two radiation belt probes (GS-RBSP) and two ionosphere-thermosphere probes (GS-ITSP) will study the effects of solar-driven storms on regions of geospace that profoundly influence the operation of critical technological systems. Strong synergism exists with SDO (described above) and between the two Geospace Network components. Scientific and programmatic closure will be achieved by comparisons with geospace models.

The Geospace Network will seek to understand and characterize:

• Radiation belt dynamics and underlying physical mechanisms including the acceleration, global distribution, and variability of radiation belt electrons and ions that produce the harsh space environment for spacecraft and humans;

• Mid-latitude ionospheric variability and the irregularities that affect communications and navigation systems as well as space assets; and

• The energetic and dynamical coupling between the mid-latitude ionosphere/thermosphere, the plasmasphere, and the ring current.

The Geospace Network addresses two fundamental processes of space physics—particle acceleration and ionosphere-thermosphere-magnetosphere coupling—each of which plays important roles in space weather. Energetic particles in the radiation belts pose a serious radiation hazard to astronauts and spacecraft systems alike, especially during magnetic storms. These particles can have a detrimental impact on communications satellites and on astronauts who remain closer to Earth in the early exploration phase. Understanding of particle acceleration derived from the Geospace Network will contribute to basic knowledge of processes occurring in solar flares and in the radiation belts of other planets. Understanding of ionosphere-thermosphere-magnetosphere coupling is directly relevant to questions about how space weather effects influence a planet’s upper atmosphere.

NASA STP, Pre-AO, launch 2015

The overall objective of the GEC mission is to understand the electrodynamic processes in Earth’s lower ionosphere and thermosphere. The mission consists of four spacecraft that will fly in formation at altitudes as low as 135 km and can independently change orbit to directly measure electrical currents that connect from high altitudes to denser regions in the lower ionosphere. The mission seeks to determine the extent and nature of the magnetosphere-ionosphere-thermosphere coupling. While primarily targeted at terrestrial processes, the science of GEC is applicable to neutral/ionospheric boundaries throughout the solar system.

The GEC mission will investigate:

• Energy transfers from the magnetosphere to the ionosphere and thermosphere, and

• Ionosphere-thermosphere coupling, revealed by measurements of the dissipation of the transferred magnetospheric energy.

Current understanding and modeling of the upper atmospheres of planets is based on terrestrial observations and processes. The basic physics of magnetosphere-ionosphere-thermosphere coupling is common to other planetary systems, specifically terrestrial planets such as Mars, and is best studied in the more readily accessible terrestrial environment. GEC will significantly improve our understanding of space weather processes in the lower ionosphere that are particularly relevant to NASA’s research support to the DOD.

Under study, NASA Science and Technology Definition Team

Solar Probe is a mission of exploration through the heliosphere and into the Sun’s outer corona (4-10 solar radii), the latter being a region never before directly explored and a region where many of the fundamental physical processes that drive the Sun-Earth system are generated. The solar wind is an extension of the solar corona that carves out the heliosphere and shapes planetary magnetospheres. A comprehensive knowledge of our space environment depends on a detailed understanding of the basic local physics as well as global morphology and the dynamics behind this interplay. The Solar Probe mission includes both in situ and remote sensing instruments on the spacecraft to fully characterize and understand the source regions and mechanisms governing the generation and flow of the solar wind, which links the Sun’s magnetic field to the Earth and beyond.

Solar Probe will seek to determine:

• The origin of the solar wind;

• Why the hot corona exists around the Sun;

• How the solar wind is accelerated;

• The mechanisms that store, accelerate, and transport energetic particles;

• The role of the plasma turbulence near the Sun;

• The quantitative relation between remote observations and the underlying fundamental physics of the corona; and

• The coronal magnetic field strength.

Solar Probe is clearly linked to the exploration initiative in two ways. First, it is itself a mission of exploration to study the solar system frontier of the local environment of the Sun. Second and more generally, it is relevant since the Sun is the main driver of the space environment that future piloted and robotic missions must traverse. A main goal of the LWS mission line is a linked operational model system of the entire inner heliosphere in order to predict and characterize space weather. Solar Probe will directly explore the solar atmosphere where solar flares and CMES are formed and propagate, and where energetic particles are accelerated, thus providing unique information about the plasma close to the Sun as well as throughout the heliosphere. Solar Probe is also driving innovative technology development that might later be applicable to exploration missions, in particular, technology that will allow spacecraft to survive extreme temperature conditions (>2000 kelvin near the Sun).

NASA LWS, recommended in the solar and space physics decadal survey report

The Multisatellite Heliospheric Mission, designated as the Inner Heliospheric Sentinels mission in the 2003 SEC Roadmap document, consists of four spacecraft in different elliptical orbits around the Sun such that, during various phases of the mission, two diamond-shaped configurations sense simultaneously both radial and azimuthal structure within interplanetary solar disturbances. These solar sentinels will study the formation and evolution of eruptions and flares from the Sun to Earth’s magnetosphere, and they will try to explore and characterize the connection between solar events and geospace disturbances.

The Multisatellite Heliospheric Mission is intended to determine:

• How the global character of the inner heliosphere changes with time,

• How geo-effective structures (coronal mass ejections, shocks, corotating interaction regions) propagate and evolve from the Sun to 1 AU,

• Which solar dynamic processes are responsible for the release of energetic particles and geoeffective events, and

• Heliospheric models.

Solar interplanetary disturbances drive interplanetary shock waves that energize charged particles, which ultimately impact planetary environments and spacecraft. The Multisatellite Heliospheric Mission/Sentinels will lead to better understanding of the role of the interplanetary disturbances in modifying the radiation environment that poses dangers to the astronauts, spacecraft, and instruments of the exploration initiative.

European Space Agency mission, confirmed, launch October 2013

U.S. scientists are members of the ESA Science Definition Team and Payload Working Group; U.S. contribution to the science payload is foreseen; Solar Orbiter is a key element of International LWS.

By approaching as close as 48 solar radii, the Solar Orbiter will view the solar atmosphere with unprecedented spatial resolution and will measure in situ properties of the inner heliosphere, a region hitherto not directly explored. Over extended periods, the Solar Orbiter will deliver images and data of the solar polar regions and the side of the Sun not visible from Earth. The Solar Orbiter will co-rotate with solar active regions and be able to view the dynamic processes of flares and coronal mass ejections with very high precision.

The Solar Orbiter will investigate:

• The in situ properties and dynamics of plasma, fields, and particles in the near-Sun heliosphere;

• The fine detail of the Sun’s magnetized atmosphere using a camera capable of detecting solar features as small as 35 kilometers across;

• The links between activity on the Sun’s surface and the resulting evolution of the corona and inner heliosphere using solar co-rotation passes; and

• The Sun’s polar regions and equatorial corona from high latitudes.

The Solar Orbiter will explore the inner heliosphere where many of the processes critically affecting the exploration initiative occur. For example, by directly measuring the acceleration and transport of solar energetic particles, scientists hope to be able to make accurate predictions as to their occurrence and intensity. Moreover, Solar Orbiter will be able to gain a unique view of the origins of solar activity, and, by combining co-rotating remote sensing views with in situ observations of subsequent inner heliospheric processes, Solar Orbiter will help to characterize the consequences of solar activity and enable accurate prediction of space weather.

Mission concept, recommended in the solar and space physics decadal survey report

MAP will address the question of how the upper atmosphere of Mars is affected by solar variability. The interaction of the martian atmosphere with the solar wind is uniquely complicated by the absence of a global magnetic field and the presence of patchy crustal remnant fields on Mars. MAP will be a low-altitude, circular polar orbiter with a minimum mission duration of one martian year. The mission will probe Mars’s upper atmosphere, ionosphere, and the interactions of Mar’s atmosphere and strong, patchy magnetic field with the solar wind.

The MAP mission will determine:

• Upper martian atmospheric composition, thermal profile, and global circulation;

• The properties of the martian ionosphere, its sources and sinks, its electrodynamic response to the solar wind, and its variability; and

• The response of the upper martian atmosphere to solar activity.

The landing of larger and more complex payloads—and eventually humans—on Mars will require ever more sophisticated entry, descent, and landing systems and will place increasing demands on the predictability of upper atmospheric properties like the thermospheric density profile. Both “aero-capture” at low altitudes (~30-80 km) and “aero-braking” at somewhat higher altitudes are currently envisioned for Mars exploration. The successful implementation of these orbital insertion and modification techniques will yield large savings in fuel and will increase the total payload delivered to the planet’s surface. However, they will require mature models of the martian upper atmosphere, validated by measurements from the Mars Aeronomy Probe. The atmospheric structure and dynamics and, in particular, the density profile are affected by variations in inputs from the Sun such as flares and coronal mass ejections, by inputs from the lower atmosphere like gravity waves, and by underlying crustal magnetic fields. The measurements to be returned by the Mars Aeronomy Probe and the subsequent modeling and data analysis will lead directly to predictive models for these important upper atmospheric effects.

NASA STP, recommended in the solar and space physics decadal survey report

Jupiter has a giant magnetosphere that has morphological similarities to Earth’s magnetosphere, but Jupiter’s strong magnetic field, high rotation rate, and the strong volcanic mass loading from Io create an intense outward centrifugal force that stretches the magnetic field into a disk-like configuration. Previous flyby missions and the Galileo orbiter have explored only the equatorial region of the jovian magnetosphere. From a polar orbit, a Jupiter Polar Mission can study the plasma dynamics and moon-ionosphere electromagnetic coupling, processes that transfer angular momentum from the spinning central object to the surrounding plasma and have implications for the early phases of the formation of solar and planetary systems.

The Jupiter Polar Mission can identify:

• The relative contributions of planetary rotation and the solar wind to the energy budget of the jovian magnetosphere,

• How the plasma circulates in the magnetosphere,

• The role of Io’s volcanism in providing mass that drives the circulation process,

• The charged particles responsible for the jovian aurora and how those particles become energized, and

• The electrodynamic processes that couple the jovian moons to the planet’s high-latitude ionosphere.

The objective to explore Jupiter’s moons and understand the history of the solar system makes a Jupiter Polar Mission important to the exploration initiative. A Jupiter Polar Mission would provide estimates of the angular momentum loss through the planet’s coupling to the magnetosphere, a process that is important in all giant-planet magnetospheres and that may have played a major role in the early evolution of the solar system. From a space physics perspective, Jupiter is an excellent test bed of fundamental magnetospheric processes (plasma transport, auroral emissions, particle acceleration, wave generation, and so on) under conditions very different from those experienced at Earth. A Jupiter Polar Mission will study the processes that establish the environments within which the Galilean satellites, such as Europa, reside. In turn, those environments are critical to establishing the suitability of these satellites as incubators for life. Furthermore, Jupiter’s moons are major sources of magnetospheric plasma and are electrodynamically coupled to the planet, triggering radio emissions and auroras in Jupiter’s polar regions.

Ongoing programs, active, prime missions and extended missions with multiple launches per year

After commissioning (typically 30 days after launch), all missions are transferred from a development phase to a mission operations and data analysis (MO&DA) phase. The duration of the MO&DA phase varies, but it typically extends through the prime mission—one to several years—and often through an extended mission, sometimes lasting many more years. The prime mission funding is guaranteed under the mission budget, and the extended mission funding is competitively awarded through periodic review of all ongoing missions. During the prime mission, an average of approximately 25 to 33 percent of the MO&DA budget is spent on missions operations, and the remainder is spent on science data analysis. As a percentage of total costs, the mission operations costs decrease during the extended mission. Part of the MO&DA budget goes to a Guest Investigator program that allows additional scientists to participate in exciting science from ongoing missions. The number of funded Guest Investigator proposals is a direct measure of the value of a mission to the community.

MO&DA is the lifeblood of the solar and space physics flight program. Furthermore, optimum science return in the connected Sun-heliosphere-planetary system often requires the extension of compelling sciences missions beyond their prime-mission lifetime both to exploit the continuing capabilities of the instruments and to take advantage of synergy that may arise with data from a more recently launched mission. The new science achieved during an extended mission is typically cutting-edge, providing measurements and comprehensiveness that would cost considerably more to produce in new hardware missions.

MO&DA is the vehicle through which data from all missions are returned to Earth, analyzed, archived, and made available for public use.

Ongoing programs

Research and Analysis programs include the Supporting Research and Technology (SR&T) program, the Sun-Earth Connection (SEC) Theory program, the Living With a Star (LWS) Targeted Research and Technology program, and the Sun-Earth Connection Instrument Development program.

Each of these Research and Analysis programs makes major contributions to many aspects of Sun-Earth Connection science:

• SR&T programs support individual research projects that use a wide variety of techniques including theory and modeling, analysis and interpretation of space data, development of new instrument concepts, and laboratory measurements of relevant atomic and plasma parameters.

• The SEC Theory program supports efforts to use relatively large “critical mass” groups of investigators to tackle SEC program-related problems that are beyond the scope of the nominally smaller SR&T projects.

• The LWS Targeted Research and Technology program is similar in scope to the SR&T program, but its goal is to address specifically those aspects of the connected Sun-Earth system that affect life and society on Earth.

• The Sun-Earth Connection Instrument Development program supports spacecraft-based instrument technologies that show promise for use in scientific investigations on future SEC missions.

The Research and Analysis programs contribute significantly to the knowledge base needed to pursue the exploration initiative. Theoretical and modeling studies provide a conceptual foundation for interpreting measurements and observations in the Sun-heliosphere-planetary system, including those related to martian aeronomy, the jovian system, empirical data in Earth’s near-space environment, and other regions relevant to the exploration initiative. Research and Analysis programs provide important support for innovative ideas and technology development, and they are especially well suited for training students at both undergraduate and graduate levels.

Ongoing program, active, multiple launches per year

The Suborbital program provides a wide range of cutting-edge science that enables some of the highest-resolution measurements ever made. Many of the instruments used on satellites were first developed on sounding rockets. For example, the “top-hat” electrostatic analyzer—a staple for determining particle distributions on virtually every space plasma physics mission currently flying—was first validated on sounding rocket flights. More recent examples include new detectors for dust particles in space and wave-particle correlators. Development of new instruments using the Suborbital program provides a cost-effective way of achieving high technical readiness levels with actual spaceflight heritage.

The Suborbital program provides investigations into:

• Mesosphere/ionosphere interactions,

• Auroral physics,

• Equatorial ionosphere investigation of the electrojet and spread-F phenomena,

• Polar cusp studies,

• High-resolution solar coronal imaging, and

• Magnetic reconnection.

Suborbital missions stand to produce great technological and human capital benefits for the exploration initiative because of the programs’ efficient approach to technology development and the hands-on training of the future workforce that these student-friendly missions enable. Instrument development on suborbital missions provides a key test bed for proving new experimental techniques so that exploration is carried out in the most efficient manner possible. Because these missions are low-cost with higher risk tolerance, students have the opportunity to participate directly in hardware development and operations. The experience gained is pivotal in training effective future principal investigators. Also, the results of studies performed by many suborbital missions will have direct implications on the science and technology necessary to support humans in Earth’s orbit during the early years of exploration.