Technical Digest

The Johns Hopkins University Applied Physics Laboratory (APL) has embarked on a decade-long strategic effort to enhance its level of innovation in an increasingly turbulent world. These initiatives and associated critical contributions reflect a vibrant organization that can look to its future with excitement. Through these pursuits, APL staff members have learned that just having great ideas is not enough. Good ideas are almost never immediately appreciated; persistence is needed to implement those innovative ideas in the face of inertia to maintain the status quo. This article first reviews APL’s efforts to overcome inertia in achieving some of its defining innovations. It recalls the persistence and deep expertise that APL has pursued to establish these inflection points in history. It then introduces the variety of articles in this special issue looking toward APL at its centennial in 2042. The expectation is that the breakthroughs these articles describe represent the Lab’s future defining innovations.

The Defense Advanced Research Projects Agency’s Revolutionizing Prosthetics program demonstrated the potential for neural interface technologies, enabling patients to control and feel a prosthetic arm and hand, and even pilot an aircraft in simulation. These landmark achievements required invasive, chronically implanted penetrating electrode arrays, which are fundamentally incompatible with applications for the able-bodied warfighter or for long-term clinical applications. Noninvasive neural recording approaches have not been as effective, suffering from severe limitations in temporal and spatial resolution, signal-to-noise ratio, depth penetration, portability, and cost. To help close these gaps, researchers at the Johns Hopkins University Applied Physics Laboratory (APL) are exploring optical techniques that record correlates of neural activity through either hemodynamic signatures or neural tissue motion as represented by the fast optical signal. Although these two signatures differ in terms of spatiotemporal resolution and depth at which the neural activity is recorded, they provide a path to realizing a portable, low-cost, high-performance brain–computer interface. If successful, this work will help usher in a new era of computing at the speed of thought.

Despite advances in knowledge and technology, approaches to health care discovery and delivery have not broadly kept pace with those advancements. While there have been notable improvements in shaping diagnosis and treatment resulting from knowledge made available through advances in technology, the field generally uses broad population characteristics as the basis for determining the health of, and how to treat, individuals. Today, with the confluence of big data and artificial intelligence (AI), we have an opportunity to tailor diagnoses and treatments precisely as needed for an individual—in other words, to practice precision medicine. The Johns Hopkins University Applied Physics Laboratory (APL) and Johns Hopkins Medicine (JHM), in partnership with the Bloomberg School of Public Health, Johns Hopkins Information Technology, and others across the institution, are working to usher in this new paradigm. These organizations jointly developed the Precision Medicine Analytics Platform (PMAP). This platform pulls data from many sources, aggregates the data, and then provisions needed data to approved researchers in a secure environment where they can apply advanced techniques and other tools to analyze the data. The guiding vision is to create and sustain the ability to accelerate gaining knowledge and value from data and from closing the loop between discovery and delivery, ultimately reducing health care costs and improving patient outcomes.

Breakthroughs the Johns Hopkins University Applied Physics Laboratory (APL) made in small satellites and hosted payloads in 2010–2020 are helping to pave the way for the future in ubiquitous sensing from space. Leveraging its extensive knowledge of space engineering, advanced miniaturization techniques, and a proven capability to meet new challenges, APL is making important contributions that enable a future in which our planet can be managed with prognostic sensing and communication at spatial and temporal scales heretofore unheard of. Small satellites will usher in this new era of utilizing space assets for improving life on Earth and extending humanity’s reach into the cosmos, with APL positioning itself to help lead the way with stand-alone, rideshare, and constellation mission concepts.

Over the past 15 years, the Johns Hopkins University Applied Physics Laboratory (APL) and others have developed and demonstrated impressive capabilities and technologies in optical communications. APL has conducted experiments, performed analysis, investigated designs, developed capabilities, coded algorithms, and conducted successful demonstrations. The critical optical communications challenge remaining for APL to solve over the next two decades is not in technology development. It is in partnering with the Department of Defense and national security space communities to apply and implement these technological achievements through the systems engineering and acquisition processes. This article discusses the history of optical communications, APL’s contributions in several domains, current challenges, and the way forward.

Intelligent systems are already having a remarkable impact on society. Future advancements could have an even greater impact by empowering people through human–machine teaming, addressing challenges with vast geographic scales, and accelerating interstellar discovery. Creating intelligent systems that can be trusted to operate autonomously is a grand challenge for humanity. In this article, we explore potential futures for trustworthy autonomous systems, identify some of the significant challenges, and illustrate potential pathways by describing developments underway at the Johns Hopkins University Applied Physics Laboratory (APL).

The Department of Defense has dealt with a multiplicity of threats throughout its history, including espionage and insider threats, as well as chemical, biological, radiological, nuclear, and explosive threats. As the department has increasingly incorporated cyber components into weapons and supporting systems in recent decades, threats from cyberattack have taken their place alongside these existing threats. At the same time, traditional cyber defenses designed to keep cyber invaders out of our systems have not always proven effective. This article discusses cyber resilience as a means for helping to ensure mission survivability despite adverse events in cyber. The article covers the state of cyber today, why cyber can be so vulnerable, and how resilience techniques can complement traditional cyber defenses to help ensure the larger mission. The article concludes with a discussion of cyber and cyber resilience in the future.

Hypersonic technologies have been investigated for more than six decades, and important operational capabilities exist in the form of reentry, space lift, and interceptor systems. Today, new classes of hypersonic weapons capabilities are emerging throughout the world. This article provides a brief overview of the history, today’s state of the art, and the future potential for hypersonics.

Data science emerged as a popular technical field by leveraging the advances in data storage, computing, and machine learning. Practical applications of data science are far-reaching and include marketing, fraud detection, logistics, crime prediction, social engagement, sports team management, and health care. Recognizing this profound impact, the Johns Hopkins University Applied Physics Laboratory (APL) Asymmetric Operations Sector (AOS) created the Data Science Initiative (DSI) to apply data science to national security challenges and health care. The DSI accelerated APL data science contributions to national security and health care by creating new research initiatives and establishing deep technical competencies that shaped and directed novel solutions across the AOS mission space.

Doomsday scenarios of near-Earth objects (asteroids and comets) hitting Earth are fodder for action movies and science fiction books, but the potential for such an event cannot be dismissed as mere fiction. In 2022, the Johns Hopkins University Applied Physics Laboratory (APL) will demonstrate an important step in planetary defense, mitigating the threat of a direct hit by developing the ability to prevent an impact to Earth. DART (Double Asteroid Redirection Test) is a NASA mission managed by APL with support from several NASA centers. DART launches in 2021 and will be the first demonstration of the kinetic impactor technique to change the motion of an asteroid in space. As the first kinetic impactor far from Earth, DART will prove the ability to deflect catastrophic threats and lead to innovations in impactor/redirect technologies. This article explains DART’s novelty and extrapolates how it might shape the future of planetary defense.

Additive manufacturing (AM, also known as 3-D printing) technologies offer the potential to revolutionize the creation of parts, disrupt supply chains, and positively affect every major industry in existence today. However, technical challenges are preventing the full vision of AM from being realized. The Johns Hopkins University Applied Physics Laboratory (APL) uses AM extensively to create prototypes and functional parts in support of its missions. This article summarizes the current state of the art, provides poignant examples of current AM capabilities, and offers a glimpse of the future potential.

Since 2010, the Johns Hopkins University Applied Physics Laboratory (APL) has been executing a strategy to enhance innovation at the Lab, both in its culture and in its practices. The expectation has been that this environment will increase the prospects for APL staff members to create new defining innovations—game-changing developments that profoundly advance science, engineering, and national security capabilities—even as the global innovation ecosystem rapidly changes. Established research findings on innovation principles, along with APL’s own experiments, informed the development of an integrated, complementary suite of innovation initiatives. This article tells the story of how these initiatives were introduced and how they have impacted, and continue to impact, APL’s culture and creative ideas.

The Research and Exploratory Development (RED) Mission Area is the research engine of the Johns Hopkins University Applied Physics Laboratory (APL). Its pioneering research, whether internally or externally funded, targets game-changing breakthroughs in national security technologies and capabilities. Through its independent research and development (IRAD) program, the RED Mission Area invests in the early phase of technology development, emphasizing the exploration of bold ideas and the development of advanced prototypes. This article describes the mission area’s IRAD strategy and process and introduces a series of articles featuring a selection of current IRAD initiatives. This groundbreaking research being conducted today will invent the future for APL and its sponsors, ensuring our nation’s preeminence when APL turns 100.

By integrating artificial intelligence with next-generation sequencing technology, autonomous surveillance of ecosystem health is possible. This article describes the work a Johns Hopkins University Applied Physics Laboratory (APL) team is doing toward autonomous anomaly detection within biological ecosystems.

After establishing the four principles of Trustworthy Synthetic Biology—safety, assuredness, efficiency, and robustness—a team of researchers at the Johns Hopkins University Applied Physics Laboratory (APL) generated trustworthy plant sensor and reporter systems. Their work, initially funded as an APL independent research and development project, has since transitioned to a sponsor-funded project.

Because of their low power requirement and fast switching, Van der Waals layered chalcogenide superlattices have performed well in dynamic resistive memories in what is known as interfacial phase change memory devices.

A Johns Hopkins Applied Physics Laboratory (APL) team developed infrared (IR) metasurface imaging lenses designed to selectively focus specific states of polarized light (linear and circular) to different locations on a detector array. The lenses’ operational characteristics make them well suited to miniaturize future optical sensor systems planned for deployment on small platforms or personnel that cannot support the volume or mass of large optical sensor systems.

Holographic metasurfaces, tailored to exhibit a precise electromagnetic response from a low profile, are a powerful platform for wavefront manipulation and present the possibility to substantially simplify the architecture of increasingly popular (and increasingly complex) digital phased arrays. This article describes the work a Johns Hopkins University Applied Physics Laboratory (APL) team is doing in this area.

This article describes an ongoing Johns Hopkins University Applied Physics Laboratory (APL) fundamental additive manufacturing study to fabricate large-scale (up to 10 × 10 × 13 in.³) shape-memory alloy components with locally tailored actuation stroke, force, and activation temperature.

Metal matrix composites (MMCs), with their unique property combinations, have the potential to enable disruptive capabilities for extreme environment applications that require high performance from materials. A Johns Hopkins University Applied Physics Laboratory (APL) team successfully produced an aluminum-silicon carbide system with additive manufacturing (AM). The team also demonstrated the ability to grade the metal and ceramic three-dimensionally to form tailored material gradients. This effort merely scratches the surface of what is possible; future advances in AM materials development could result in materials with properties that are currently impossible to achieve with any other manufacturing process. These materials could benefit many applications.

This article describes a Johns Hopkins University Applied Physics Laboratory (APL) strategic independent research and development project exploring multifunctional hypersonic components and structures. The project was envisioned to develop transformational materials technologies and expertise that could be applied to relevant hypersonic vehicle programs supported at APL.

While the use of metal additive manufacturing (AM) has grown immensely over the past decade, there still exists a gap in understanding of process defects in AM, which often inhibit its use in critical applications such as flight hardware. The Johns Hopkins University Applied Physics Laboratory (APL) is developing novel techniques to replicate authentic surrogate defects in AM parts and characterize their effect on mechanical response. Advanced data processing methods, such as machine learning, are being leveraged to develop predictive failure models, which will help enhance our understanding of the effects of defects.

Optimal quantum control theory identifies the quantum equivalent of a matched filter, which maximizes the signal-to-noise ratio, enabling exploitation of extremely high sensitivity of quantum sensors to detect known signals of interest. This article describes a Johns Hopkins University Applied Physics Laboratory (APL) team’s work in this field.

With deep neural networks (DNNs) being used increasingly in many applications, it is critical to improve our understanding of their failure modes and potential mitigations. A Johns Hopkins University Applied Physics Laboratory (APL) team successfully inserted a backdoor (train-time attack) into a common object detection model. In conjunction with this research, they developed a principled methodology to evaluate patch attacks (test-time attacks) and the factors impacting their success. Their approach enabled the creation of a novel optimization framework for the first-ever design of semitransparent patches that can overcome scale limitations while retaining desirable factors with regard to deployment and detectability.

In this article, we describe the work of a team of researchers from the Johns Hopkins University Applied Physics Laboratory (APL) and Johns Hopkins University (JHU) to develop adaptive crowd navigation policies for robots by reasoning and predicting future pedestrian motion.

For complex artificially intelligent systems to be incorporated into applications where safety is critical, the systems must be safe and reliable. This article describes work a Johns Hopkins University Applied Physics Laboratory (APL) team is doing toward verifying safety in artificial intelligence and reinforcement learning systems.

The Motifs to Models team at the Johns Hopkins University Applied Physics Laboratory (APL) leverages the existence proof provided by biological circuitry—of robustness, adaptability, and low-sample learning at very low size, weight, and power—to explore novel computational substrates toward critical sponsor needs in computation and artificial intelligence.

In the NeuroSwarms framework, a team including researchers from the Johns Hopkins University Applied Physics Laboratory (APL) and the Johns Hopkins University School of Medicine (JHM) applied key theoretical concepts from neuroscience to models of distributed multi-agent autonomous systems and found that complex swarming behaviors arise from simple learning rules used by the mammalian brain.

New propulsion technologies are critical to developing new capabilities in Department of Defense platforms. An innovative approach taking nuclear heat and directly generating DC electric power with solid-state thermoelectric devices, without the need for a steam power plant, can lead to reliable and compact systems while offering several system-level advantages. These advanced thermal-to-electric device developments are also applicable to efficient radioisotope thermoelectric generators (RTGs) for space outer-planetary missions. Similarly, many platforms, and special operations in particular, need very compact (lightweight, small volume) pulse electric power sources with high specific power density in the range of ~1,000 kW/kg and a long shelf life. This article describes progress with fundamental scientific advances relevant to these thermal-to-electric conversion applications leveraging recent advances in nano-engineered thin-film thermoelectric materials.

Fixed-wing unmanned aerial vehicles (UAVs) offer significant performance advantages over rotary-wing UAVs in terms of speed, endurance, and efficiency. However, these vehicles have traditionally been severely limited in terms of maneuverability. Through technical advancements in controls and platform design, the Johns Hopkins University Applied Physics Laboratory (APL) is widening the flight envelope for autonomous fixed-wing UAVs.

Liquid crystal elastomer (LCE)–based soft robots with reversible actuation could be beneficial for both Department of Defense and civilian applications, including in exploration of confined spaces, payload delivery, remote sensing and data collection, and small biomedical devices. In the work described in this article, we developed a first-principle model for designing high-work-capacity LCEs. Further, we built bilayer structures for actuation applications. We then built a Bluetooth-controlled soft robotic system and quantified its performance. The article also discusses the outlook for LCE-based soft robotics for Department of Defense applications.

A team at the Johns Hopkins University Applied Physics Laboratory (APL) developed SIMoN (System Integration with Multiscale Networks), a framework that connects predictive resource models from domains such as water, electricity, climate, and population, and passes data about resource usage and availability between models. SIMoN is useful for interfacing models with different native environments and geospatial definitions and can potentially be adapted to many other applications.

Materials that selectively actuate in response to chemicals in the environment can serve as the foundation for new sensing platforms that take advantage of innate chemical reactivities to provide low-power, selective sensing of chemical agents. A Johns Hopkins University Applied Physics Laboratory (APL) team designed an organophosphate-sensing platform, called DetectsVX, that uses a hydrogel. Initial demonstrations of sensors based on this selectively actuating material have been successful, and the team is currently pursuing innovations in both hydrogel chemistry and sensing mode.

Although predicting the future is a difficult task, in many ways the Research and Exploratory Development Department (REDD) at the Johns Hopkins University Applied Physics Laboratory (APL) exists to do just that. The department’s researchers seek to envision future challenges for APL and the nation and develop innovative solutions to those challenges. This brief article begins with a framework for thinking about what APL research and development will look like when the Lab reaches its centennial. Then it discusses some key areas of research that we predict will be active in 2042.

As the Johns Hopkins University Applied Physics Laboratory (APL) looks toward its 100th anniversary in 2042, its leaders are undertaking strategic planning efforts to imagine the challenges the future Lab—and indeed the future nation and world—will face. APL’s Asymmetric Operations Sector (AOS) created envisioned futures for 13 challenges spanning its four mission areas, Cyber Operations, Special Operations, Homeland Protection, and National Health, and is focusing its efforts on creating disruptive technical solutions to realize these envisioned futures. This article describes the envisioned futures and the strategic efforts involved in their formulation.

As the role of technology continues to expand around the world, rigorous, multidisciplinary analysis is increasingly needed to inform technical solutions to the nation’s most pressing challenges. With their deep technical and operational knowledge, analysts at the Johns Hopkins University Applied Physics Laboratory (APL) have long partnered with senior government decision-makers to help them solve immediate challenges and to envision and prepare for future challenges. These partnerships will be stronger than ever when APL celebrates its 100th anniversary in 2042, as APL continues to provide the robust, insightful, and well-communicated analysis that our nation’s senior leaders require.

Astrobiology is an exciting field of science focused on understanding the origins, evolution, distribution, and future of life in the universe. NASA focuses much of its research and technology developments on astrobiology, and the Johns Hopkins University Applied Physics Laboratory (APL) is a major contributor through research, technology, and missions. Astrobiology efforts at APL range from constraining when life first emerged on Earth and researching biosignature (i.e., signals of past or present life) preservation, to developing instruments and missions aiming to detect biosignatures and characterize the capability of an extreme planetary environment to harbor and support life. Beginning with APL’s Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on the Mars Reconnaissance Orbiter (MRO), which searches for past wet and potentially habitable regions on Mars, APL has continued to develop cutting-edge techniques and instruments to search for biosignatures, remotely and in situ. Additionally, APL is leading and serving as a key partner in several exciting NASA missions that will occur in the coming decades with habitability and biosignature detection goals. In this article, we summarize current efforts and look forward, over the coming 25 years, to the potential astrobiology exploration and discoveries that await.

Since the development of the proximity fuze in 1942, the Johns Hopkins University Applied Physics Laboratory (APL) has been leading the nation in the development of air and missile defense capabilities to defend our military forces, our allies, and the nation. Throughout these 78 years APL has strived to solve many of the most critical challenges in air and missile defense and in doing so has made critical contributions to the nation. As we look toward APL’s centennial in 2042, global threats to our nation’s military, allies, and homeland are evolving at a pace that will significantly challenge today’s air and missile defenses. This article describes the grand challenges in future air and missile defense and how APL, by anticipating these future warfighting environments and leveraging technology innovations, is working to revolutionize air and missile defense to ensure our nation’s preeminence in the 21st century.

This article describes the context, foundation, and features of APL’s Communications Department, which formed in the summer of 2020. Although the department is not yet a year old as of this writing, a story of its trajectory might reveal insights about its future.

The Johns Hopkins University Applied Physics Laboratory (APL) has had a long history of campus land planning, beginning with its purchase of a 290-acre property in Laurel, Maryland in 1952. With the APL campus currently encompassing nearly 500 acres including owned and leased properties, the Laboratory faces several challenges in planning for future development. First it is hitting ceilings on available land on which to build. The continued tightening of government regulations, including environmental and zoning requirements, limits APL’s property development potential to approximately 250 acres. Second is the increasing complexity of the facilities APL requires today. Facilities often need to be uniquely tailored to meet specific sponsor or program needs, limiting their ability to be repurposed later. Third is the continued land planning efforts necessary to address the ever-evolving workplace requirements and needs of APL staff. Beyond simply indicating where staff are to work, development plans must fully consider how staff need to work. In response to these challenges, the Laboratory undertook a new master planning effort for its campus. The subsequent new Campus Master Plan, developed during the Campus Development Process, is grounded in the Laboratory’s core values and addresses the evolving aspects of technology, sponsor needs, environmental and regulatory requirements, and workplace culture and effectiveness.

When the Johns Hopkins University Applied Physics Laboratory (APL) reaches its 100th anniversary in 2042, its workforce can be expected to comprise a broad set of technical capabilities and staff attributes, some new and others enduring and recognizable from the Lab’s history. This article reviews APL’s workforce of 2020, discusses how that workforce and the work being performed are changing, and looks ahead at the workforce of APL at its centennial.

Graduate-level education has been the cornerstone for developing the capabilities of staff members of the Johns Hopkins University Applied Physics Laboratory (APL) and those of neighboring governmental and industrial organizations for over five decades. This article briefly discusses the development of graduate-level engineering and applied science education at APL along with its strong historical ties to the Johns Hopkins University Whiting School of Engineering. In particular, this article focuses on the 2020 education upheaval caused by the COVID-19 pandemic and offers thoughts about what the future may hold in store for graduate-level professional education at APL and its Whiting School partner.

Autonomous systems are becoming increasingly integrated into all aspects of our lives. To work toward ensuring these systems are safe, secure, and reliable and operate as designed, the Johns Hopkins University established the Johns Hopkins Institute for Assured Autonomy (IAA), run jointly by its Applied Physics Laboratory (APL) and the Whiting School of Engineering. The IAA takes a holistic approach to assuring autonomous systems by working across three pillars: increasing reliability of the technology, improving interactions within the integrated ecosystem, and engendering trust through policy and governance. This article discusses the need for the IAA, its goals and approach, and some of its initial research efforts.

For nearly 60 years the Johns Hopkins University Applied Physics Laboratory (APL) has collaborated with Johns Hopkins Medicine (JHM) to study pressing health and health care problems and develop innovative solutions. Early accomplishments in ophthalmology, neurophysiology, oncology, and cardiology led to better understanding of and new and improved treatments for various conditions. Today, through its National Heath Mission Area, APL is furthering its partnership with JHM to apply rigorous data analysis and systems engineering practices to the diagnosis and treatment of disease. The collaboration leverages the institutions’ systems engineering and medical expertise to create a learning health system that will speed the translation of knowledge to practice while enabling new discoveries through the development and application of advanced analytic tools. This article briefly describes how the partnership has revolutionized health and health care and is poised to continue to do so.

This article and the illustrations that follow highlight what members of APL’s Young Professionals Network (YPN) think the Lab might look like when it reaches its centennial. YPN aims to assist early-career staff members build community and develop their careers, while giving them the opportunity to help shape the future of the Lab by providing input on APL leadership’s strategic planning directions. Today’s YPN members will be at the height of their careers—and possibly APL’s leaders—in 2042, so their insights are especially valuable.

This article pays tribute to Kenneth Moscati, longtime senior illustrator for the Technical Digest, who died March 15, 2021. Ken made major contributions to APL’s technical illustrations, large environmental displays, and publications, particularly the Technical Digest.