Raytheon Technologies (Netherlands)

The January 2022 Hunga Tonga–Hunga Haʻapai eruption was one of the most explosive volcanic events observed in the modern era, producing a vertical plume which peaked more than 50km above the Earth. The initial explosion and subsequent plume triggered atmospheric waves which propagated around the world multiple times. Here, we combine a comprehensive set of satellite and ground-based observations to analyse and quantify this wave response, from surface to ionosphere. A broad spectrum of waves was triggered by the initial explosion, including Lamb waves propagating at 318.2±6 ms-1 at surface level and between 308±5 to 319±4 ms-1 in the stratosphere, and fast gravity waves propagating at 238±3 to 269±3 ms-1 in the stratosphere. Atmospheric gravity waves at sub-ionospheric heights have not previously been observed propagating either at this speed or over the whole Earth from a single identifiable source. Latent heat release from water and hot ash in the plume remained the most significant individual gravity wave source at any location for the next 12 hours, producing circular wavefronts visible across the Pacific basin in satellite gravity wave observations. A single source dominating such a large region is also unique in the observational record. The Hunga Tonga eruption represents a key natural experiment in how the atmosphere responds to a sudden point-source-driven state change, which will be of significant use for improving atmospheric weather and climate models.

View Video Presentation: https://doi.org/10.2514/6.2022-1214.vid The Mars 2020 Entry Descent and Landing (EDL) system delivered the Perseverance rover to the surface of Mars on February 18th, 2021. A large fraction of the Jezero Crater landing site was covered with landing hazards including cliffs, inescapable dune fields and rocks. These hazards were identified or inferred using orbital imagery before launch so that they could be avoided using Terrain Relative Navigation (TRN) which was composed of two parts: the Lander Vision System (LVS) and Safe Target Selection (STS). During EDL, the LVS successfully estimated map relative position by fusing landmarks matched between descent imagery and a map of the landing site with Inertial Measurement Unit (IMU) data. This position estimate was used by STS to identify the safest target for landing that was also reachable given fuel and other constraints. The EDL system then used the powered descent phase to retarget to this location and land safely. The overall error between the targeted location and actual landing location was 5m which was an order of magnitude less than the 60m touchdown error requirement. This paper will describe the final tests of the LVS before launch, the checkout of the LVS during operations and the LVS performance during EDL.

The January 2022 Hunga Tonga–Hunga Haʻapai eruption was one of the most explosive volcanic events of the modern era, producing a vertical plume which peaked > 50km above the Earth. The initial explosion and subsequent plume triggered atmospheric waves which propagated around the world multiple times. A global-scale wave response of this magnitude from a single source has not previously been observed. Here we show the details of this response, using a comprehensive set of satellite and ground-based observations to quantify it from surface to ionosphere. A broad spectrum of waves was triggered by the initial explosion, including Lamb waves5,6 propagating at phase speeds of 318.2+/-6 ms-1 at surface level and between 308+/-5 to 319+/-4 ms-1 in the stratosphere, and gravity waves propagating at 238+/-3 to 269+/-3 ms-1 in the stratosphere. Gravity waves at sub-ionospheric heights have not previously been observed propagating at this speed or over the whole Earth from a single source. Latent heat release from the plume remained the most significant individual gravity wave source worldwide for >12 hours, producing circular wavefronts visible across the Pacific basin in satellite observations. A single source dominating such a large region is also unique in the observational record. The Hunga Tonga eruption represents a key natural experiment in how the atmosphere responds to a sudden point-source-driven state change, which will be of use for improving weather and climate models.

<h3>Abstract</h3> Satellite-based augmentation systems ensure the accuracy and integrity of aircraft position estimates derived from radio signals broadcast by the Global Navigation Satellite System. The United States’ Wide Area Augmentation System (WAAS) protects users of the Global Positioning System from threats generated by ionospheric disturbances. The means by which WAAS mitigates these threats depends upon their magnitude. This paper addresses: a) how WAAS monitors the level of ionospheric perturbation over North America; b) how various availability and integrity concerns have influenced the implementation of WAAS’s extreme and moderate ionospheric storm detectors; c) how the algorithms governing these implementations have evolved since WAAS’s commissioning in 2003; and d) how the largest ionospheric storms of the past two solar cycles can be ranked according to their impact on WAAS. A subsequent companion paper will address the evolution of the WAAS methodology for protecting users from the adverse influence of more moderate ionospheric disturbances.

Abstract The Future of Systems Engineering (FuSE) is an INCOSE‐led multiorganizational collaborative initiative pursuing INCOSE's Vision 2025 and beyond. To accomplish this the FuSE initiative encompasses a number of topic areas with active projects to shape the future of systems engineering. This paper addresses the FuSE Security topic area and provides a roadmap of eleven foundational concepts for building the security vision. The purpose of this paper is to instigate and inspire thinking and involvement in the development and practice of the foundational concepts.

The DARPA Millimeter Wave Digital Arrays (MIDAS) program is demonstrating the first element level digital millimeter wave phased arrays covering the 18-50 GHz band. The performers are leveraging compound semiconductors, CMOS and heterogeneous integration to meet the stringent size and power constraints while pushing the state-of-the-art in RF and mixed-signal design. The 4×4 element dual-polarized transceiver tile will be a building block to enable scalable arrays mobile-to-mobile ad-hoc networking and emerging proliferated low-earth orbit (LEO) satcom. Element-level digital beamforming has the potential to enable multi-beam operation for reduced network discovery time and increased network throughput.

Business travel leads to the consumption of large amounts of energy. Circuit World (CW), a Unity virtual environment, uses avatars and realistic simulations of electrical circuits to test the effectiveness of teaching complex engineering tasks without travel. To evaluate CW, a study compares how well participants learn to repair a circuit when trained face-to-face, via Zoom, and within CW wearing an HMD. After training and completion of a knowledge quiz, learners are given a circuit to repair by themselves using a non-immersive desktop version of CW. Participants repair it again two weeks later to test retention. Each study session involves three people: learner, trainer, and researcher. The learner and trainer control avatars and the researcher, invisible, observes over the learner's shoulder. Collected data includes task performance logs from CW, knowledge quiz scores, and, based on video recordings, eye gaze tracking, behavioral coding, and measures of facial synchrony between trainer and learner.

This paper evaluates the merits of a multi-variable Gaussian process regression (GPR) model for remaining useful life (RUL) estimation. The paper presents an optimization method that trains the GPR model to find the best kernel type and hyper-parameter combination. Furthermore, the paper evaluates the performance of the GPR model for small training datasets and with a reduction (missing) of input features. A comparison is made to the multi-layer perceptron (MLP) neural network which forms the basis of deep learning models. To illustrate model performance, an air filter clogging RUL dataset is used. The performance results show that both GPR and MLP models have similar sensitivity to training set size but GPR also computes the uncertainty. Empirically, MLP is more robust to a test set with a missing input while the data suggests that the GPR performs better when the training data also did not include the same input.

Abstract There is considerable number of architectural frameworks and standards with many pertinent definitions of concepts that are often not compatible with each other, hindering collaboration, especially in the context of System of Systems (SoS). To address this issue, we propose an ontology for SoS that uses Object Process Methodology (OPM) ISO 19450 to facilitate collaboration among organizations with focus on safety aspects. The current effort focuses on the foundational extended taxonomy that uses a minimal set of terms to model system‐ and SoS‐related concepts and relations among them to streamline collaboration among involved SoS stakeholders, with focus on safety. The ontology is illustrated through an example of a self‐parking facility.

Aircraft industry is seeing a paradigm shift towards more electric-based operation, increasing requirements for electrical wiring systems exponentially in terms of frequency and voltage stress. Traditionally, aircraft power transmission cables are unshielded and placed close to ground plane and communication infrastructures. These demand rethinking of aircraft standards viz DO-160G and different cable interconnection systems. This paper investigates various cable options to handle the increased load demand and its impact on electromagnetic interactions and reflected wave phenomenon. It was noted that separately shielded cable generates 59% less common-mode noise generation but aids in 23% higher reflected wave overvoltage as opposed to unshielded cable configuration.

ABSTRACT The Aerospace &amp; Defense (A &amp; D) industries maintain a high level of interest in the expansive amount of work performed in developing and qualifying Pb-free solder alloys. The three main areas of interest continue to be thermal cycle, mechanical shock, and vibration. The past twenty years have seen an unprecedented increase in alloy development such that the concepts of “generations of solders and “families of solders” have been coined to help manage the numerous individual alloys on the market today. This paper will discuss work done with Pb-free solder alloys, many with the addition of constituents focusing on varying property enhancements. The purpose is to provide a “snap shot” summary of progress to date and relate perspectives both as advantages and concerns solely in a constructive manner to aid researchers in planning their next steps in development and qualification of these alloys.

High speed and high rotor tip-speed, in particular, combined with high magnetic and electrical loading, are key enablers for obtaining high specific power in electric machines. The rotor described in this paper pushes the tip speed to about 80% of the speed of sound. An outer rotor design with a carbon-fiber retaining ring on the outer diameter (OD) was chosen to maintain high magnetic loading in the airgap while ensuring structural integrity at high speed. To achieve manufactural feasibility, a cantilevered rotor structure was proposed to suspend the rotor around the stator. This architecture introduces significant rotordynamic challenges, one of which is the ”trunnion effect,” a rotordynamic effect uncommon in traditional electric machines. This effect was identified when a discrepancy was observed during a rotor test and a root-cause analysis was performed to explain it. The original rotor dynamic model was modified to include this effect, and verified through a ping test. The trunnion effect, which significantly reduces the critical speeds, can be offset by selecting appropriate dimensions for the rotor end plate using the revised model. Thus, even in the presence of this effect, the proposed unconventional motor topology is confirmed to function reliably.

Mars Polar Science is an integrated, compelling system that serves as a nearby analogue to numerous other planets, supports human exploration, and habitability. Mars possesses the closest and most easily accessible layered ice deposits outside of Earth, and accessing those layers to read the climate record would be a triumph for planetary science.

There has been a boost in optoelectronic device technology that can leverage strengths of both optical and electronic worlds to support high-voltage and high-speed operation. It is critical to characterize the RF performance from the measured signals of these devices in order to evaluate their performance, optimize their designs and also aid in better understanding of the device physics. Conventional curve-fitting models either fail to fit measured signals with high accuracy or provide limited, if any, information about the device physics. Here, we propose a Prony-based curve-fitting method to characterize RF pulse measurements from such optoelectronic devices. The performance of the overall algorithm on measurement data shows high accuracy, with the capability to extract key pulse parameters such as full width at half maximum and rise time. Additionally, the capability of the method to extract time constants associated with semiconductor traps can help in better understanding of optoelectronic device physics.

A compact frequency-doubled diode-pumped Nd:YAG master-oscillator power-amplifier laser system with programmable microsecond pulse length has been developed. Analog pulse shaping of the output from a single-frequency continuous-wave Nd:YAG oscillator, and subsequent amplification, allowed the generation of rectangular pulses with pulse lengths on the order of the Nd:YAG fluorescence lifetime. Temporally flat-top pulses of 1064 nm light with 520 mJ pulse energy, 2.6 kW peak power, and 200 μ s duration, with linewidth below 10 kHz, were obtained at a repetition rate of 2 Hz. Second harmonic generation in a LBO crystal yielded pulses of 262 mJ and 1.3 kW peak power at 532 nm. The peak power can be maintained within 2.9% over the duration of the laser pulse, and long-term intensity stability of 1.1% was observed. The spatially flat-top beam at 1064 nm used in the amplifier is converted to a Gaussian beam at 532 nm with beam quality factor M 2 = 1.41(14) during the second harmonic generation. This system has potential as a pump source for Ti:sapphire, dye, or optical parametric amplifiers to generate tunable high-power single-frequency radiation for applications in precision measurements and laser slowing.

Abstract A core challenge in modern systems engineering is executing the Digital Transformation to produce Digital Engineering (DE) products that meet traditional program needs. Model Based Systems Engineering (MBSE) focuses the formal application of models to support the systems engineering process, but is often difficult to apply in practice due to a lack of a well‐defined methodology. This paper first introduces an openly available MBSE methodology concentrating on a development process for system architecture models, a style guide defining how the process steps are executed, and a validation suite which serves as a tool to help execute development. Then, this paper describes the experience in applying this process to a DoD program developing a space‐based sensor system to a Critical Design Review (CDR) level of maturity. Real‐life successes and lessoned learned are described through model metric data pulled directly from the SysML development model. This paper concludes by identifying opportunities for future research/work from which to further build the DE/MBSE capabilities of the model.

Objective evidence shows whether contemporary engineering students are engaged by transdisciplinary education. This is done by first using a diffusion of innovations approach that isolates “transdisciplinary engineering” occurrences on the Internet from occurrences of disciplinary engineering, and then showing trends, forming conclusions, and making recommendations.

Software and information technologies are becoming increasingly integrated and pervasive in human society, and range from automated decision making to running critical infrastructure like utilities and financial institutions. There is also a growing awareness of the need to develop leaders who will harness these technologies in fair and inclusive ways. Many academic and industry researchers are advocating for the responsible use of information technologies and some academic and research institutions such as IEEE and ACM have published codes of ethics to spread awareness about these issues. In this regard, a number of academic researchers, including the authors of this paper, have expressed the need to teach students computer and information ethics as well as professional and leadership skills. In this paper, we propose an approach that is potentially effective in helping students develop leadership and communication skills as well as learn broader skills of professional responsibility. The proposed approach is modeled after Toastmasters, a very successful association present in over 140 countries with almost 350,000 members across more than 16,000 clubs. We describe our goal and give a general description of a Toastmasters club and how it is conducted. Further, we describe some activities and projects having CS/SE context that can be done by students as part of a relevant class. Finally, we briefly describe the approach that we are undertaking in our first pilot activities and their integration with additional synergetic strategies.

The shift from gold (Au) to copper (Cu) wire bonds used in PEMs (Plastic Encapsulated Microcircuits) has been gradual for the last few years. Many agencies and critics question the long-term robustness and reliability of Cu wire bonds; however, PEM manufacturers have been thoroughly evaluating and optimizing the Cu wire bond process over the last few years to produce highly reliable products. When the manufacturing process is optimized and closely controlled and monitored, Cu wire bonds can be a reliable and stronger alternate to Au wire bonds. This paper details a Cu wire bond study that specifically compares Cu wires against Au wire bonds following combined environmental stress/life test conditions. In this study, bond pull testing indicated good performance of both copper and gold wire bonds. The methods used in this analysis (Destructive Physical Analysis (DPA), wire pull testing and environmental testing) were effective techniques for evaluation of bond wire integrity, detection of manufacturing defects, and overall assessment of the copper and gold wire bond processes. Based on wire bond testing in this analysis, the reliability/integrity of optimally developed copper wire bonds appears to be superior or even stronger than gold wires in the same package type.

We consider the probabilistic planning problem where a robot (called Player 1, or P1) can jointly plan the control actions and sensor queries in a sensor network and an attacker (called player 2, or P2) can carry out attacks on the sensors. We model such an adversarial interaction using a formal model-a reachability game with partially controllable observation functions. The main contribution of this paper is to assess the cost of P1’s unawareness: Suppose P1 misinterprets the sensor failures as probabilistic node failures due to unreliable network communication, and P2 is aware of P1’s misinterpretation and P1’s partial observability. Then, from which states can P2 carry out sensor attacks to ensure, with probability one, that P1 will not be able to complete her reachability task even though, due to misinterpretation, P1 believes that she can almost-surely achieve her task. We develop an algorithm to solve the almost-sure winning sensor-attack strategy given P1’s observation-based strategy. Our attack analysis could be used for attack detection in wireless communication networks and the design of provably secured attack-aware sensor allocation in decision-theoretic models for cyber-physical systems.