The newly published magnetic control plan for TRACERS, described in the journal Space Science Reviews, lays out in unusual detail how the team confronted this challenge. The stakes are concrete and quantifiable. The mission’s fluxgate magnetometer, MAG, must measure the local DC magnetic field with an accuracy of 100 nanotesla at a temporal resolution of 0.1 seconds, while the magnetic search coil, MSC, must capture AC fields from 1 to 1000 hertz. The overlapping frequency ranges were deliberately defined around the science performed by the two instruments, with the fluxgate covering zero to 50 hertz and the search coil extending to kilohertz frequencies. A third instrument, the MAGIC technology demonstration, also senses fields from zero to 50 hertz, but as a do-no-harm technology payload it imposes no requirements on the host mission.

Contamination comes in several distinct flavors. Static magnetic fields from magnetized or ferromagnetic materials directly corrupt the measured low-frequency and static field, while time-varying electrical currents contaminate the AC measurements. Perhaps less obviously, the ACE electron instrument is also a victim: stray magnetic fields near its aperture, at frequencies below the local electron gyrofrequency of roughly one megahertz, deflect incoming lower-energy electrons and blur the angular resolution of the measurement, altering the apparent direction at which particles arrive. The control plan therefore had to protect three separate classes of sensors, each with different sensitivities and different tolerances, mounted on a spacecraft packed with batteries, heaters, latch valves, reaction wheels, and electronics that all generate magnetic signatures of their own.

The first line of defense was distance. Magnetic fields from localized sources decay rapidly, roughly as the cube of the distance, so simply moving sensors away from noise sources buys enormous leverage. The baseline design placed the fluxgate and search coil sensors 100 centimeters from the spacecraft body on two-segment non-magnetic deployable booms. But in a twist that reshaped the entire magnetic strategy, a flight boom failed during environmental testing late in the mission, forcing engineers to adopt a 70-centimeter fixed rigid bracket instead. The change was made possible by the generous volume available when TRACERS was assigned the top, so-called cake-topper position on a SpaceX Falcon 9, but it meant the plan had to be re-evaluated around the reduced separation and the resulting amplification of apparent noise.

Source control came next. The team used a preferred and discouraged materials list, drawing on heritage guidance from NASA magnetic cleanliness studies, to steer part selections away from ferromagnetic components. Where magnetic parts were unavoidable, geometry became the tool: latching relays, which are inherently magnetic because of their internal permanent magnets, were arranged in mirrored pairs so their stray fields partially cancel. The batteries, whose asymmetric string-cell configuration generates a field dependent on charge and discharge current, were placed near the center of the spacecraft and arranged back-to-back to reduce the magnetic moment in two axes. Latch valve assemblies were oriented in opposite directions for the same reason, and heaters were fabricated with self-cancelling current trace paths. Notably, the team declined to use compensating permanent magnets, wary of creating strong local fields near the ACE electron instrument mounted on a spacecraft face sheet.

Electrical design rules targeted the time-varying half of the problem. All harnessing used balanced twisted pairs to provide dedicated return paths and minimize open current loops, and subsystems were forbidden from using chassis ground for current return, instead implementing local star grounding. The solar panels were back-wired, following techniques pioneered on the Magnetospheric Multiscale mission, so that interconnects ran anti-parallel and the bulk current flow in each panel largely cancelled itself. Special zones around the magnetometer sensors were built from non-ferromagnetic materials including aluminum, titanium, carbon fiber composites, and PEEK engineering plastic, with specialty titanium and aluminum connectors at field joints and careful grounding of the multilayer insulation to avoid open loops in ground wires.

Design alone, however, could not guarantee cleanliness, so the mission screened components and assemblies with four complementary techniques. The MAG team measured stray fields by moving test articles at fixed intervals past a magnetometer centered in a mumetal shield, repeating the test for each axis. The spacecraft provider used a much larger three-layer mumetal shield assembly for subsystems. The mission team built a semi-automated apparatus, documented in a 2024 paper, in which test articles rotate on a magnetically clean plate inside a one-meter cubic shield while three magnetometers at varying distances capture the modulated field, allowing a dipole moment to be fitted by spectral analysis. Complete instrument assemblies were simply waved by hand at a fixed distance from a stationary magnetometer as a quick clean-room check.

The screening campaign was governed by an elegant allocation scheme. Rather than predicting the exact stray field at the sensors, the plan ensured the total stayed below a maximum allowable 100 nanotesla at the MAG sensor. Each object was pro-rated against the spacecraft’s total mass, with half of the budget held in reserve for discretionary release by the magnetic control board, and random orientations assumed so sources add in quadrature, a deliberately conservative approach that overestimates the aggregate field of many point sources. A de-minimis threshold of 1 nanotesla at one meter exempted negligible parts, and objects that failed individual screening could pass as part of a higher assembly, exploiting opportunistic cancellation. In practice, the latch valves emerged as the largest stray-field offenders by a significant margin and were dispositioned as use-as-is, with their DC contribution to be removed by post-processed in-situ calibration rather than risky magnetic compensation near the electron instrument.

Perhaps the most intricate chapter concerns the two fluxgate magnetometers themselves. Mounted 50 centimeters apart on a common bracket, MAG and MAGIC form an ad-hoc gradiometer that can separate the common geophysical field from spacecraft-generated noise, but their proximity creates mutual interference. The dominant effect arises from the global negative magnetic feedback that both instruments use to null the field inside their sensors and linearize their response: the feedback windings generate a quasi-DC stray field proportional to the ambient field being cancelled. Using a Biot-Savart model originally developed to optimize the Tesseract sensor’s internal feedback field, the team simulated the external stray field of both MAGIC sensor variants and validated the predictions in a two-meter Merritt coil facility at the University of Iowa, finding a robustly linear gain error of roughly 5 nanotesla at 20,000 nanotesla that can be corrected through on-orbit calibration. A second interference path, in which the two sensors’ 8192-hertz core drive signals beat against each other, was fully eliminated by synchronizing MAGIC’s voltage-controlled oscillator to MAG’s drive signal with a pulse-width-modulated control loop.

The final safety net is software. Swing tests, adapted from the Van Allen Probes program, suspended each spacecraft from a crane and fitted a dipole model to the oscillating stray field measured by stationary magnetometers, while controlled rotations mapped the field’s angular dependence. Preliminary uncertainties of about 50 percent are being reduced by a new gradient-fitting analysis that suggests the 100-nanotesla threshold was met with margin. For the residual noise introduced by the shorter bracket, the team leaned on a discipline that has advanced dramatically in recent years: singular spectrum analysis and machine-learning techniques, proven on missions from e-POP to Parker Solar Probe, have mitigated dynamic noise sources by 89 to 95 percent, meaning TRACERS can tolerate roughly a tenfold increase in stray field at the sensors. At 70 centimeters, the predicted amplification is only about two to four times, a change assessed to leave the mission’s first two science objectives untouched, with only a low-likelihood but medium-consequence risk to the baseline closure of the third objective, which requires characterizing field-aligned currents near 100 nanotesla and Alfvén waves near 1 nanotesla. Whether the plan succeeds will be judged on orbit, where in-situ calibration offsets will validate the DC program and any unexpected AC sources will be hunted down against the catalog built during integration, closing the loop on one of the most thorough magnetic hygiene campaigns ever flown on a small-satellite mission.

Subject of Research: Magnetic cleanliness engineering for the TRACERS twin-satellite mission studying magnetic reconnection in Earth's magnetospheric cusp

Article Title: The Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites (TRACERS) Magnetic Control Plan

Article References: Miles, D. M., Lasko, A., Blandin, M., Bounds, S., Caron, R., Carton, A., Dolan, J., Dvorsky, R., Finley, M. G., Flores, A., Goss, C., Greene, K., Halekas, J., Hospodarsky, G. B., Kletzing, C. A., Mark, D., Miller, I., Nguyen, P., Omar, S., … Washington, A. (2026). The Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites (TRACERS) Magnetic Control Plan. Space Science Reviews, 222(6), Article 70. https://doi.org/10.1007/s11214-026-01326-2

Image Credits: AI Generated

DOI: 10.1007/s11214-026-01326-2

Keywords: TRACERS, magnetic cleanliness, magnetometry, fluxgate magnetometer, magnetic reconnection, magnetospheric cusp, gradiometer, stray magnetic field, MAGIC, signal processing, spacecraft screening, NASA

At the core of the IMAP payload is the Compact Dual Ion Composition Experiment (CoDICE), an innovative instrument developed and managed by SwRI. What sets CoDICE apart is its unparalleled ability to combine multiple measurement capabilities within a single patented sensor, allowing it to simultaneously analyze various ion populations in the heliosphere. This sophisticated instrument leverages advanced ion detection and spectrometry techniques to determine the distribution, mass, and composition of particles streaming through the boundary between solar and interstellar space, including interstellar pickup ions and solar wind ions associated with high-energy solar events.

The challenges of operating in the harsh environment of space, where temperatures can swing dramatically between the blistering heat of direct sunlight and the frigid cold of deep space, have been ingeniously addressed in CoDICE’s design. SwRI engineers devised a unique thermal management system for CoDICE whereby one side of the instrument is coated with a reflective “gold” surface that deflects intense solar radiation, while the opposite side bears a matte black finish engineered to absorb heat. This thermal dichotomy ensures the instrument’s components remain within operational temperature limits, safeguarding reliability and longevity throughout its mission lifespan.

Spanning roughly the size and weight of a standard five-gallon paint bucket, CoDICE packs cutting-edge technology into a compact 22-pound frame. Its innovative design not only optimizes space and weight constraints critical for spacecraft payloads but also exemplifies advances in sensor integration and miniaturization. Dr. Mihir Desai, a leading scientist on the IMAP team, highlights the elegant simplicity and robustness of this design, underscoring how it advances the frontier of space instrumentation.

Beyond CoDICE, SwRI’s contributions to IMAP extend to other vital instruments. Notably, the Institute developed the IMAP-Hi and IMAP-Lo instruments responsible for detecting energetic neutral atoms (ENAs), elusive particles that reveal information about the boundaries of interstellar space. IMAP-Lo focuses on lower-energy neutral atoms with a single-pixel imager and a conversion subsystem crafted at SwRI, while IMAP-Hi traces higher-energy ENAs. These paired instruments, operating in tandem, provide a comprehensive, multi-energy perspective of particle environments far beyond what previous missions have delivered.

Moreover, SwRI engineered the high-voltage power supplies for the Solar Wind Electron (SWE) instrument, a device measuring thermal electron distributions within the solar wind. This capability is vital to understanding the solar wind’s plasma characteristics and its influence on near-Earth and planetary space weather. Additionally, SwRI built digital electronics components for four other IMAP instruments, cementing its role as a cornerstone in the successful execution of this complex mission.

IMAP represents the next evolution in NASA’s Solar Terrestrial Probes (STP) program, which seeks to deepen humanity’s grasp of heliophysics—the study of the Sun’s influence throughout the solar system. By charting the heliosphere’s precise shape, composition, and dynamic processes, IMAP will fill longstanding gaps in our understanding of how solar material interacts with the galaxy’s interstellar environment. This knowledge is crucial for forecasting space weather phenomena that pose risks to astronauts, satellites, and critical space infrastructure.

The interaction at the heliosphere’s edge forms a natural shield that modulates the influx of cosmic rays—high-energy particles accelerated from distant astrophysical sources—that can be hazardous to both space missions and terrestrial technologies. IMAP’s detailed measurements will clarify how this barrier operates and how energetic particles are accelerated across vast interplanetary distances. Such insights are key to advancing protective technologies and mission planning for future deep-space exploration.

Led by Princeton University’s Professor David J. McComas and supported by a consortium of 27 institutions world-wide, the IMAP mission encapsulates a monumental collaborative effort. The Johns Hopkins Applied Physics Laboratory in Maryland designed and built the spacecraft and will oversee mission operations once IMAP embarks on its quest through space. This joint enterprise underscores the intersection of scientific innovation, engineering prowess, and international cooperation necessary for tackling today’s most pressing questions in space science.

SwRI’s leadership in managing the payload office and delivering cutting-edge instruments underscores its integral role in this historic mission. Spearheading the efforts, Executive Director Susan Pope serves as IMAP’s payload manager, while Dr. Mark Tapley carries responsibilities as the payload systems engineer. Their leadership ensures the coordination and harmonious integration of all instruments, amplifying the mission’s scientific return by enabling coordinated, multi-instrument observations.

The extraordinary complexity of measuring charged and neutral particles across an extraordinarily vast spatial domain demands instruments that are reliable, highly sensitive, and capable of enduring harsh conditions. IMAP’s suite of instruments, many featuring novel designs and advanced materials, represents a leap forward in heliophysics instrumentation that will set the stage for future explorations. As the mission embarks on its multi-year survey, it promises to deepen humanity’s understanding of our cosmic neighborhood and the forces shaping it.

This mission comes at a pivotal time when understanding solar influences on space weather and planetary environments is critically important not only for scientific discovery but also for the practical protection of both Earth-bound and orbital technologies. With IMAP’s impending launch, the scientific community eagerly awaits the data that will illuminate the complex processes governing our heliospheric boundary and the interplay between the Sun and galaxy.

For further details on this transformative mission and SwRI’s instrumental contributions, interested readers can visit SwRI’s heliophysics research portal, which offers extensive resources on solar and space physics research initiatives. IMAP’s launch represents a landmark achievement in solar and interstellar exploration, one that will fuel scientific inquiry and technological development for decades to come.

Subject of Research:
NASA’s Interstellar Mapping and Acceleration Probe (IMAP) mission and the role of Southwest Research Institute in developing its payload instruments, with a focus on the Compact Dual Ion Composition Experiment (CoDICE).

Article Title:
Southwest Research Institute Pioneers Advanced Ion Composition Sensor for NASA’s IMAP Mission to Map the Heliosphere

News Publication Date:
September 22, 2025

Web References:
https://www.swri.org/markets/earth-space/space-research-technology/space-science/heliophysics?&utm_medium=referralutm_source=eurekalert!&utm_campaign=imap-pr

Image Credits:
Southwest Research Institute

Keywords

Solar physics, Heliosphere, Solar wind, Cosmic rays, Interstellar space

The comet, traveling through our solar system at a breathtaking speed of 130,000 miles per hour—making it the fastest solar system visitor ever recorded—has generated considerable intrigue among astronomers and space enthusiasts alike. Such velocity suggests that it has been roaming interstellar space for eons, possibly billions of years, propelled by gravitational forces from numerous stars and other celestial bodies it has encountered on its journey. Unlike comets originating in our solar system, 3I/ATLAS’s trajectory can be described as hyperbolic, suggesting a distinct and unpredictable origin.

Hubble’s observations allow astronomers to refine their estimates regarding the comet’s nucleus size, revealing an upper limit diameter of 3.5 miles, while possibly being as small as 1,000 feet. Although the core remains elusive and obscured in the brightness of its dust envelope, Hubble continues to hone our understanding of this remarkable interstellar body. With additional observations slated from other NASA missions—including the James Webb Space Telescope and the Neil Gehrels Swift Observatory—there is great anticipation to unveil further details about the comet’s composition and potential origins.

In conjunction with the compelling images of 3I/ATLAS, Hubble also documented a dust plume fomented by the heat of the Sun that appears to emerge from the comet. The data indicate a dust-loss rate reminiscent of comets first detected at distances similar to that of 3I/ATLAS from the Sun, affirming behaviors aligned with previously observed comets in our own solar neighborhood. This sedimentary activity underlines the dynamic nature of the comet as it interacts with solar radiation, highlighting its ongoing evolution as it travels through the solar system.

One notable observation made by astronomers is the resemblance of 3I/ATLAS to some comets originating from within our own solar system. Such parallels emphasize the shared characteristics that could provide critical context to the study of cometary bodies, revealing whether interstellar visitors may possess physical attributes akin to their solar counterparts. However, it’s crucial to acknowledge the profound differences that set 3I/ATLAS apart, notably its non-solar origin from an unknown stellar system, eluding precise identification.

David Jewitt, an esteemed astronomer at the University of California, Los Angeles, and principal investigator for the Hubble observations, articulated the enigma surrounding the comet’s journey. He likened viewing 3I/ATLAS to glimpsing a high-velocity projectile, emphasizing the challenges in tracing back its cosmic trajectory and true origins—underscoring the intertwined complexities of celestial mechanics and astrodynamics.

The comet’s discovery by the NASA-funded Asteroid Terrestrial-impact Last Alert System (ATLAS) on July 1, 2025, at a distance of 420 million miles from the Sun, marked a significant milestone in the ongoing exploration of interstellar bodies. The ATLAS initiative serves as an early warning mechanism for asteroid impacts, and its identification of 3I/ATLAS represents an important contribution to the growing body of knowledge regarding such wandering celestial artifacts.

Researchers have posited that this is just the beginning of unveiling a previously obscured population of interstellar objects. Astronomers, equipped with cutting-edge observational technology, are poised to uncover further intriguing specimens that traverse our solar system, shedding light on their formation and characteristics. Each successive discovery adds to our understanding of cosmic evolution while opening exciting avenues of research into the fabric of our galaxy.

Even as the comet approaches an unseen proximity to the Sun, where its brightness may hinder future observations, expectations remain high for further insights as it will become visible again later in the year. The cosmic journey of 3I/ATLAS exemplifies the mysteries lurking beyond our immediate celestial neighborhood, promising to enrich our conception of the universe and our place within it.

The collaborative effort between NASA and international partners, along with the continued operation of the Hubble Space Telescope, will pave new paths in the search for knowledge about our cosmic surroundings. As investigations proceed, the findings from this remarkable interstellar encounter are destined not only to invite curiosity but also to ignite the imagination concerning the vastness of space and the mysteries still waiting to be unveiled.

Furthermore, as our understanding of interstellar comets like 3I/ATLAS evolves, researchers will turn their attention to the potential implications these objects hold for solar system formation theories. This serves to inspire a generation of astronomers and physicists, rekindling a sense of wonder about the natural world and the mechanisms behind the profound phenomena we observe in our galaxy and beyond.

Subject of Research:
Article Title: Hubble Space Telescope Observations of the Interstellar Interloper 3I/ATLAS
News Publication Date: July 2025
Web References: NASA
References: The Astrophysical Journal Letters
Image Credits: NASA, ESA, David Jewitt (UCLA); Image Processing: Joseph DePasquale (STScI)

Keywords

Interstellar comet, Hubble Space Telescope, 3I/ATLAS, astronomers, interstellar, cosmic, celestial mechanics, dust plume, NASA, solar system.

Lyman-alpha light, a specific ultraviolet wavelength, is crucial for astronomers studying the universe. It emerges during interactions involving hydrogen, a fundamental element in stellar and galactic evolution. These emissions are invaluable for understanding the composition, temperature, and motion of distant celestial bodies. The utility of Lyman-alpha observations extends to probing the characteristics of the interstellar medium and evaluating the processes that contribute to star formation and galactic formation.

During its historic journey to Pluto, the New Horizons spacecraft utilized the Alice spectrograph—a specialized instrument developed by SwRI—to collect baseline data regarding Lyman-alpha emissions. This spectrograph is adept at dissecting light into its constituent colors, enabling a thorough analysis of the ultraviolet spectrum. By employing Alice, researchers gathered fundamental insights about the Lyman-alpha emissions that envelop our solar system, enhancing our knowledge of the interstellar environment.

Following the successful completion of its primary mission objectives at Pluto, the New Horizons team began to conduct extensive surveys of Lyman-alpha emissions more frequently as the spacecraft ventured further from the Sun. This expanded exploration culminated in comprehensive scans of approximately 83% of the celestial sphere in 2023, effectively creating a map that highlights the distribution of Lyman alpha emissions across the sky surrounding our solar system. The scale of this observation is unprecedented, making it a landmark achievement for both the mission and astrophysics.

A pivotal aspect of this research was the isolation of galactic emissions from other sources of Lyman-alpha light. The scientists designed a comprehensive model to account for solar Lyman-alpha emissions, allowing them to subtract these contributions from Alice’s spectrographic data. The results illuminated a relatively uniform background brightness of Lyman-alpha light that was tenfold stronger than previously anticipated, shedding light on the intricate dynamics occurring within nearby galactic structures.

Dr. Randy Gladstone, leading investigator of the study, emphasizes the significance of comprehending the Lyman-alpha background. He notes that it offers revealing insights into the interactions between our solar system and its surrounding cosmic environment. The research proposes that hot interstellar gas bubbles, such as the one encapsulating our solar system, may exhibit regions of intensified hydrogen gas emissions observable at the Lyman-alpha wavelength. This reaffirms our notions about the interconnectedness of galactic phenomena.

The findings prompted scientists to reconsider previous theories about the nature of a hydrogen wall believed to surround the Sun’s heliosphere. This wall was posited as a barrier formed by the accumulation of interstellar hydrogen atoms at the boundary of the heliosphere, influencing the measurements of Lyman-alpha emissions. Notably, the collected data from New Horizons revealed no substantial contributions from this hypothesized structure, challenging long-held views and prompting deeper investigations into the realities of our galactic surroundings.

This research serves not only to validate existing knowledge but also fosters the emergence of new questions about the nature of space and the universe at large. Co-author Dr. Alan Stern expresses enthusiasm about the findings, as they provide a fresh perspective on the galactic structures surrounding the solar system. These landmark observations open a path for future explorations that could further broaden our comprehension of astrophysics and the forces at play within our galaxy.

The meticulous culmination of these observations and analyses has been documented in a research paper titled “The Lyman-alpha Sky as Observed by New Horizons at 57 AU,” authored predominantly by Dr. Gladstone and his team. This paper is now featured in The Astronomical Journal, making the insights accessible to a broader audience of scientists and researchers. The possibility for continued inquiries into Lyman-alpha emissions presents a promising avenue for the exploration of interstellar physics and the ongoing evolution of our understanding of the universe.

As scientists build on the groundwork laid by this study, they remain optimistic about the potential for future missions and observations to further unravel the mysteries of the cosmos, leading to enhanced comprehension of the phenomena shaping the universe. The ongoing journey of discoveries in the realm of astrophysics stands testament to the advances made possible by technological innovations in space exploration. The insights gained from the New Horizons mission not only illuminate our immediate galactic environment but also inspire an enduring curiosity about the expansive universe that extends far beyond our solar system.

Continued exploration will be fundamental in expanding our understanding of Lyman-alpha emissions and their role in the greater galactic context. As new data comes to light, the scientific community eagerly anticipates further revelations about the interstellar medium and the cosmic tapestry of which our solar system is a minor yet significant part. The collaboration of diverse scientific minds within missions like New Horizons ensures that the legacy of exploration contributes to a profound collective understanding of the universe, fostering an environment of growth for future astronomical discoveries.

The impact of this research extends beyond academia; it calls for public interest and engagement in space science. As findings such as these reach the general populace, they inspire the next generation of astronomers and scientists to pursue careers in STEM fields. The continuous unfolding of knowledge from space missions underscores the importance of investment in scientific research, which ultimately enriches our understanding of the world beyond our own.

Through the lens of the New Horizons mission and its groundbreaking work on Lyman-alpha emissions, we find an invigorating narrative of scientific inquiry. This narrative demonstrates the intertwined relationship between exploration, inquiry, and discovery as we continue to navigate the vast expanse of the cosmos and our place within it. The pursuit of knowledge leads us through a chapter of remarkable achievements, driven by human curiosity and the unyielding quest to unveil the mysteries scattered across the universe.

Subject of Research: Lyman-alpha emissions and their implications for interstellar medium exploration.
Article Title: The Lyman-alpha Sky as Observed by New Horizons at 57 AU
News Publication Date: April 28, 2025
Web References: The Astronomical Journal
References: Not applicable.
Image Credits: Credit: Southwest Research Institute

Keywords

Lyman-alpha emissions, New Horizons mission, galactic map, ultraviolet light, hydrogen atoms, interstellar medium, astrophysics.