Showing papers presented at "IEEE Aerospace Conference in 2013"

A UAV system for inspection of industrial facilities

Abstract: This work presents a small-scale Unmanned Aerial System (UAS) capable of performing inspection tasks in enclosed industrial environments. Vehicles with such capabilities have the potential to reduce human involvement in hazardous tasks and can minimize facility outage periods. The results presented generalize to UAS exploration tasks in almost any GPS-denied indoor environment. The contribution of this work is twofold. First, results from autonomous flights inside an industrial boiler of a power plant are presented. A lightweight, vision-aided inertial navigation system provides reliable state estimates under difficult environmental conditions typical for such sites. It relies solely on measurements from an on-board MEMS inertial measurement unit and a pair of cameras arranged in a classical stereo configuration. A model-predictive controller allows for efficient trajectory following and enables flight in close proximity to the boiler surface. As a second contribution, we highlight ongoing developments by displaying state estimation and structure recovery results acquired with an integrated visual/inertial sensor that will be employed on future aerial service robotic platforms. A tight integration in hardware facilitates spatial and temporal calibration of the different sensors and thus enables more accurate and robust ego-motion estimates. Comparison with ground truth obtained from a laser tracker shows that such a sensor can provide motion estimates with drift rates of only few centimeters over the period of a typical flight.

The open prototype for educational NanoSats: Fixing the other side of the small satellite cost equation

Abstract: Government supported nano-satellite launch programs and emerging commercial small satellite launch services are reducing the cost of access to space for educational and other CubeSat projects. The cost and complexity of designing and building these satellites remains a vexing complication for many would be CubeSat aspirants. The Open Prototype for Educational NanoSats (OPEN), a proposed nano-satellite development platform, is described in this paper. OPEN endeavors to reduce the costs and risks associated with educational, government and commercial nano-satellite development. OPEN provides free and publicly available plans for building, testing and operating a versatile, low-cost satellite, based on the standardized CubeSat form-factor. OPEN consists of public-domain educational reference plans, complete with engineering schematics, CAD files, construction and test instructions as well as ancillary reference materials relevant to satellite building and operation. By making the plan, to produce a small but capable spacecraft freely available, OPEN seeks to lower the barriers to access on the other side (non-launch costs) of the satellite cost equation.

Considerations for Software Defined Networking (SDN): Approaches and use cases

Abstract: Software Defined Networking (SDN) is an evolutionary approach to network design and functionality based on the ability to programmatically modify the behavior of network devices. SDN uses user-customizable and configurable software that's independent of hardware to enable networked systems to expand data flow control.

TiME - The Titan Mare Explorer

Abstract: The Titan Mare Explorer (TiME) is a Discovery-class mission concept that underwent a detailed Phase A study in 2011–2012. The mission would splashdown a capsule on Titan's ethane sea Ligeia Mare as early as the summer of 2023, and would spend multiple Titan days performing science measurements and transmitting data directly back to Earth. This paper reviews briefly the mission concept.

Analytical algorithms to quantify the uncertainty in remaining useful life prediction

Abstract: This paper investigates the use of analytical algorithms to quantify the uncertainty in the remaining useful life (RUL) estimate of components used in aerospace applications. The prediction of RUL is affected by several sources of uncertainty and it is important to systematically quantify their combined effect by computing the uncertainty in the RUL prediction in order to aid risk assessment, risk mitigation, and decision-making. While sampling-based algorithms have been conventionally used for quantifying the uncertainty in RUL, analytical algorithms are computationally cheaper and sometimes, are better suited for online decision-making. While exact analytical algorithms are available only for certain special cases (for e.g., linear models with Gaussian variables), effective approximations can be made using the first-order second moment method (FOSM), the first-order reliabilitymethod (FORM), and the inverse first-order reliabilitymethod (Inverse FORM). These methods can be used not only to calculate the entire probability distribution of RUL but also to obtain probability bounds on RUL. This paper explains these three methods in detail and illustrates them using the state-space model of a lithium-ion battery.

Robot strings: Long, thin continuum robots

Abstract: We describe and discuss the development of long, thin, continuous “string-like” robots aimed at Space exploration missions. These continuous backbone “continuum” robots are inspired by numerous biological structures, particularly vines, worms, and the tongues of animals such as the anteater. The key novelty is the high length-to-diameter ratio of the robots. This morphology offers penetration into, and exploration of, significantly narrower and deeper environments than accessible using current robot technology. In this paper, we introduce new design alternatives for long thin continuum robots, based on an analysis and extension of three core existing continuum robot design types. The designs are evaluated based on their mechanical feasibility, structural properties, kinematic simplicity, and degrees of freedom.

Decoding static and dynamic arm and hand gestures from the JPL BioSleeve

Abstract: This paper presents methods for inferring arm and hand gestures from forearm surface electromyography (EMG) sensors and an inertial measurement unit (IMU). These sensors, together with their electronics, are packaged in an easily donned device, termed the BioSleeve, worn on the forearm. The gestures decoded from BioSleeve signals can provide natural user interface commands to computers and robots, without encumbering the users hands and without problems that hinder camera-based systems. Potential aerospace applications for this technology include gesture-based crew-autonomy interfaces, high degree of freedom robot teleoperation, and astronauts' control of power-assisted gloves during extra-vehicular activity (EVA). We have developed techniques to interpret both static (stationary) and dynamic (time-varying) gestures from the BioSleeve signals, enabling a diverse and adaptable command library. For static gestures, we achieved over 96% accuracy on 17 gestures and nearly 100% accuracy on 11 gestures, based solely on EMG signals. Nine dynamic gestures were decoded with an accuracy of 99%. This combination of wearableEMGand IMU hardware and accurate algorithms for decoding both static and dynamic gestures thus shows promise for natural user interface applications.

Model based systems engineering (MBSE) applied to Radio Aurora Explorer (RAX) CubeSat mission operational scenarios

Abstract: Small satellites are more highly resource-constrained by mass, power, volume, delivery timelines, and financial cost relative to their larger counterparts. Small satellites are operationally challenging because subsystem functions are coupled and constrained by the limited available commodities (e.g. data, energy, and access times to ground resources). Furthermore, additional operational complexities arise because small satellite components are physically integrated, which may yield thermal or radio frequency interference.

OPALS: An optical communications technology demonstration from the International Space Station

Abstract: Optical communication using space borne lasers has long promised to increase the amount of science data transmitted down to Earth. A first step in achieving operational capability is demonstrating the fundamentals of the optical link in an equivalent environment. The International Space Station, with its vast capability, is well suited to accommodate payloads aimed at advancing the readiness of such technologies.

Preliminary assessment of the Mars Science Laboratory entry, descent, and landing simulation

Abstract: On August 5, 2012, the Mars Science Laboratory rover, Curiosity, successfully landed inside Gale Crater. This landing was the seventh successful landing and fourth rover to be delivered to Mars. Weighing nearly one metric ton, Curiosity is the largest and most complex rover ever sent to investigate another planet. Safely landing such a large payload required an innovative Entry, Descent, and Landing system, which included the first guided entry at Mars, the largest supersonic parachute ever flown at Mars, and the novel Sky Crane landing system. A complete, end-to-end, six degree-of-freedom, multi-body computer simulation of the Mars Science Laboratory Entry, Descent, and Landing sequence was developed at the NASA Langley Research Center. In-flight data gathered during the successful landing is compared to pre-flight statistical distributions, predicted by the simulation. These comparisons provide insight into both the accuracy of the simulation and the overall performance of the Entry, Descent, and Landing system.

VASSAR: Value assessment of system architectures using rules

Abstract: A key step of the mission development process is the selection of a system architecture, i.e., the layout of the major high-level system design decisions. This step typically involves the identification of a set of candidate architectures and a cost-benefit analysis to compare them. Computational tools have been used in the past to bring rigor and consistency into this process. These tools can automatically generate architectures by enumerating different combinations of decisions and options. They can also evaluate these architectures by applying cost models and simplified performance models.

Inter-satellite links for cubesats

Abstract: Realizing inter-satellite links is a must for ensuring the success of cubesat swarm missions. Nevertheless, it has hardly been considered until now. The communication systems for cubesats have to deal with a few peculiar demands regarding consumed power, geometry and throughput. Depending on the type of application, required data rates can go up to tens of megabits per second, while power consumption and physical size are limited by the platform. The proposed communication scheme will combine power-efficient modulation and channel coding with multiple access and spread spectrum techniques, enabling the deployment of multiple satellites. Apart from this, the antenna system has to be designed such that links can be established and maintained independent of the satellites' orientation. An electrically steerable radiation pattern is achieved by placing antennas on each face of the cube. Conformal beamforming provides the system with 5 dBi gain for any desired direction of transmission, eliminating the need for attitude control. Furthermore, using planar antennas reduces the complexity of the mechanical part as they require no deployment.

Feasibility analysis for a manned mars free-return mission in 2018

Abstract: In 1998 Patel et al searched for Earth-Mars free-return trajectories that leave Earth, fly by Mars, and return to Earth without any deterministic maneuvers after Trans-Mars Injection. They found fast trajectory opportunities occurring two times every 15 years with a 1.4-year duration, significantly less than most Mars free return trajectories, which take up to 3.5 years. This paper investigates these fast trajectories. It also determines the launch and life support feasibility of flying such a mission using hardware expected to be available in time for an optimized fast trajectory opportunity in January, 2018.

Controllable ON-OFF adhesion for Earth orbit grappling applications

Abstract: ON-OFF adhesives can benefit multiple Earth orbit applications by providing the capability to selectively anchor two surfaces together repeatedly and releasably without significant preload. Key to this new capability, targets will not need special preparation; ON-OFF adhesives can be used with cooperative and non-cooperative objects, like defunct satellites or space debris. Using an ON-OFF adhesive gripper allows large surfaces on a target to serve as potential grapple points, reducing the precision needed in the sensing and control throughout the grapple operation. A space-rated adhesive structure is presented that can be turned ON-OFF using a slight sliding motion. This adhesive mimics the geometry and performance characteristics of the adhesive structures found on the feet of gecko lizards. Results from adhesive testing on common orbital surfaces like solar panels, thermal blankets, composites, and painted surfaces are presented. Early environmental testing results from cold temperature and vacuum tests are also presented. Finally, the paper presents the design, fabrication, and preliminary testing of a gripping mechanism enabled by these ON-OFF adhesives in preparation for satellite-servicing applications. Adhesive levels range from near zero on rough surfaces to more than 75 kPa on smooth surfaces like glass.

Ad hoc CubeSat constellations: Secondary launch coverage and distribution

Abstract: The primary purpose of a constellation is to obtain global measurements with improved spatial and temporal resolution. The small size, low cost, standardized form factor, and increasing availability of commercial parts for CubeSats make them ideal for use in constellations. However, without taking advantage of secondary payload opportunities, it would be costly to launch and distribute a CubeSat constellation into a specific configuration. A cost-effective way to launch a constellation of CubeSats is via consecutive secondary payload launch opportunities, but the resulting constellation would be an ad hoc mix of orbit parameters. We focus on the feasibility of cobbling together constellation-like functionality from multiple secondary payload opportunities. Each participating CubeSat (or set of CubeSats) per launch could have completely different orbital parameters, even without propulsion onboard the CubeSats or intermediate transfer carriers. We look at the ground coverages that could be obtained for a constellation of five to six orbital planes with one to six satellites in each plane. We analyze past and announced future launch opportunities for CubeSats, including launch platforms supported by the NASA Educational Launch of Nanosatellites (ELaNa). We consider combinations of possible launch locations and temporal spacings over the course of one year and simulate the resulting ground coverage patterns and revisit times for an ad hoc constellation using these launch opportunities. We perform this analysis for two separate case studies - one with only US launches and one with both US and non-US opportunities - and vary the number of satellites per orbital plane. Typical CubeSat mission lifetimes and deorbit times for low-altitude orbits are included in these analyses. The ad hoc constellation results are compared to coverage from uniformly-placed LEO constellations and are quantified in terms of revisit time, time to 100% global coverage, and response time. For multiple satellites per orbital plane, we identify the required delta-V and expected time to distribute these CubeSats in non-traditional constellation architectures. We find that using secondary launches for opportunistic ad hoc CubeSat constellations, if not limited to US-only opportunities, can decrease global satellite revisit time when compared with a uniform Walker constellation (6 hours versus 8 hours for the Walker constellation). The ad hoc constellation is slightly less optimal than the Walker constellation in terms of response time (13 hours versus 12 hours) and time to complete global coverage (12 hours versus 10 hours), but the performance is comparable.

Regolith Advanced Surface Systems Operations Robot (RASSOR)

Abstract: Regolith is abundant on extra-terrestrial surfaces and is the source of many resources such as oxygen, hydrogen, titanium, aluminum, iron, silica and other valuable materials, which can be used to make rocket propellant, consumables for life support, radiation protection barrier shields, landing pads, blast protection berms, roads, habitats and other structures and devices. Recent data from the Moon also indicates that there are substantial deposits of water ice in permanently shadowed crater regions and possibly under an over burden of regolith. The key to being able to use this regolith and acquire the resources, is being able to manipulate it with robotic excavation and hauling machinery that can survive and operate in these very extreme extra-terrestrial surface environments.

Model based document and report generation for systems engineering

Abstract: As Model Based Systems Engineering (MBSE) practices gain adoption, various approaches have been developed in order to simplify and automate the process of generating documents from models. Essentially, all of these techniques can be unified around the concept of producing different views of the model according to the needs of the intended audience. In this paper, we will describe a technique developed at JPL of applying SysML Viewpoints and Views to generate documents and reports. An architecture of model-based view and document generation will be presented, and the necessary extensions to SysML with associated rationale will be explained. A survey of examples will highlight a variety of views that can be generated, and will provide some insight into how collaboration and integration is enabled. We will also describe the basic architecture for the enterprise applications that support this approach.

Autonomous mission operations

Abstract: NASA's Advanced Exploration Systems Autonomous Mission Operations (AMO) project conducted an empirical investigation of the impact of time delay on today's mission operations, and of the effect of processes and mission support tools designed to mitigate time-delay related impacts. Mission operation scenarios were designed for NASA's Deep Space Habitat (DSH), an analog spacecraft habitat, covering a range of activities including nominal objectives, DSH system failures, and crew medical emergencies. The scenarios were simulated at time delay values representative of Lunar (1.2–5 sec), Near Earth Object (NEO) (50 sec) and Mars (300 sec) missions. Each combination of operational scenario and time delay was tested in a Baseline configuration, designed to reflect present-day operations of the International Space Station, and a Mitigation configuration in which a variety of software tools, information displays, and crew-ground communications protocols were employed to assist both crews and Flight Control Team (FCT) members with the long-delay conditions. Preliminary findings indicate: 1) Workload of both crewmembers and FCT members generally increased along with increasing time delay. 2) Advanced procedure execution viewers, caution and warning tools, and communications protocols such as text messaging decreased the workload of both flight controllers and crew, and decreased the difficulty of coordinating activities. 3) Whereas crew workload ratings increased between 50 sec and 300 sec of time delay in the Baseline configuration, workload ratings decreased (or remained flat) in the Mitigation configuration.

Optimization and experimental validation of electrostatic adhesive geometry

Abstract: This paper introduces a method to optimize the electrode geometry of electrostatic adhesives for robotic gripping, attachment, and manipulation applications. Electrostatic adhesion is achieved by applying a high voltage potential, on the order of kV, to a set of electrodes, which generates an electric field. The electric field polarizes the substrate material and creates an adhesion force. Previous attempts at creating electro-static adhesives have shown them to be effective, but researchers have made no effort to optimize the electrode configuration and geometry. We have shown that by optimizing the geometry of the electrode configuration, the electric field strength, and therefore the adhesion force, is enhanced. To accomplish this, Comsol Multiphysics was utilized to evaluate the average electric field generated by a given electrode geometry. Several electrode patterns were evaluated, including parallel conductors, concentric circles, Hilbert curves (a fractal geometry) and spirals. The arrangement of the electrodes in concentric circles with varying electrode widths proved to be the most effective. The most effective sizing was to use the smallest gap spacing allowable coupled with a variable electrode width. These results were experimentally validated on several different surfaces including drywall, wood, tile, glass, and steel. A new manufacturing process allowing for the fabrication of thin, conformal electro-static adhesive pads was utilized. By combining the optimized electrode geometry with the new fabrication process we are able to demonstrate a marked improvement of up to 500% in shear pressure when compared to previously published values.

Bayesian framework for aerospace gas turbine engine prognostics

Abstract: Prognostics is an emerging capability of modern health monitoring that aims to increase the fidelity of failure predictions. In the aerospace industry, it is a key technology to maximise aircraft availability, offering a route to increase time in-service and reduce operational disruption through improved asset management.

Spacecraft/rover hybrids for the exploration of small Solar System bodies

Abstract: In this paper we present a mission architecture for the systematic and affordable in-situ exploration of small Solar System bodies (such as asteroids, comets, and Martian moons). At a general level, a mother spacecraft would deploy on the surface of a small body one, or several, spacecraft/rover hybrids, which are small (< 5 kg, ≈ 15 Watts), multi-faceted robots enclosing three mutually orthogonal flywheels and surrounded by external spikes (in particular, there is no external propulsion). By accelerating/decelerating the flywheels and by exploiting the low gravity environment, the hybrids would be capable of performing both long excursions (by hopping) and short traverses to specific locations (through a sequence of controlled “tumbles”). Their control would rely on synergistic operations with the mother spacecraft (where most of hybrids perception and localization functionalities would be hosted), which would make the platforms minimalistic and in turn the entire mission architecture affordable. Specifically, in the first part of the paper we present preliminary models and laboratory experiments for the hybrids, first-order estimates for critical subsystems, and a preliminary study for synergistic mission operations. In the second part, we tailor our mission architecture to the exploration of Mars' moon Phobos. The mission aims at exploring Phobos' Stickney crater, whose spectral similarities with C-type asteroids and variety of terrain properties make it a particularly interesting exploration target to address both high-priority science for the Martian system and strategic knowledge gaps for the future human exploration of Mars.

A new framework to integrate wireless sensor networks with cloud computing

Abstract: Wireless sensors networks have several applications of their own. These applications can further enhanced by integrating a local wireless sensor network to internet, which can be used in real time applications where the results of sensors are stored on the cloud. We propose an architecture that integrates a wireless sensor network to the internet using cloud technology. The resultant system is proved to be reliable, available and extensible. In this paper a new framework is proposed for WSN integration with Cloud computing model, existing WSN will be connected to the proposed framework. Three deployment layer are used to serve user request (IaaS, PaaS, SaaS) either from the library which is made from data collected from data centric DC by WSN periodically. The integration controller unit of the proposed framework integrates the sensor network and cloud computing technology which offers reliability, availability and extensibility.

CommCube 1 and 2: A CubeSat series of missions to enhance communication capabilities for CubeSat

Abstract: CubeSats and small satellites are becoming a way to explore space and to perform science more affordably. As the goals for these spacecraft become more ambitious in terms of physical distance (moving from Low Earth Orbit (LEO) to Geostationary Earth Orbit (GEO) or further), and of the amount of data to relay back to Earth (from Kbits to Mbits), the communication systems currently implemented will not be able to fully support those missions. Two of the possible strategies to solve this issue are the following: 1. Increasing the time available to communicate to the ground by using existing satellite networks as communication relays. 2. Equipping the satellite with a more powerful antenna compatible with the volume and mass constraints imposed by CubeSats and small satellites.

Mapping planetary caves with an autonomous, heterogeneous robot team

Abstract: Caves on other planetary bodies offer sheltered habitat for future human explorers and numerous clues to a planet's past for scientists. While recent orbital imagery provides exciting new details about cave entrances on the Moon and Mars, the interiors of these caves are still unknown and not observable from orbit. Multi-robot teams offer unique solutions for exploration and modeling subsurface voids during precursor missions. Robot teams that are diverse in terms of size, mobility, sensing, and capability can provide great advantages, but this diversity, coupled with inherently distinct low-level behavior architectures, makes coordination a challenge. This paper presents a framework that consists of an autonomous frontier and capability-based task generator, a distributed market-based strategy for coordinating and allocating tasks to the different team members, and a communication paradigm for seamless interaction between the different robots in the system. Robots have different sensors, (in the representative robot team used for testing: 2D mapping sensors, 3D modeling sensors, or no exteroceptive sensors), and varying levels of mobility. Tasks are generated to explore, model, and take science samples. Based on an individual robot's capability and associated cost for executing a generated task, a robot is autonomously selected for task execution. The robots create coarse online maps and store collected data for high resolution offline modeling. The coordination approach has been field tested at a mock cave site with highly-unstructured natural terrain, as well as an outdoor patio area. Initial results are promising for applicability of the proposed multi-robot framework to exploration and modeling of planetary caves.

Wireline deep drill for exploration of Mars, Europa, and Enceladus

Abstract: One of the most pressing current questions in space science is whether life has ever arisen anywhere else in the universe. Water is a critical prerequisite for all life-as-we-know-it, thus the possible exploration targets for extraterrestrial life are bodies that have or had copious liquid: Mars, Europa, and Enceladus. Due to the oxidizing nature of Mars' surface, as well as subsurface liquid water reservoirs present on Europa and Enceladus, the search for evidence of existing life must likely focus on subsurface locations, at depths sufficient to support liquid water or retain biologic signatures.

CubeSat mission design based on a systems engineering approach

Abstract: With the exception of the CubeSat specification, CubeSat design and development approaches have been mostly ad hoc, which has questioned their reliability. A systems engineering approach, based on the guidelines of NASA's Systems Engineering Handbook has been developed for CubeSats to facilitate systematic design, development and address their reliability, traceability, and reusability. The CubeSat systems engineering approach, developed as a repeatable process, uses a top-down design methodology to translate mission definitions into basic building blocks, components, interfaces and tasks, that then facilitate a bottom-up development and fabrication process. Some of the design tools (e.g., N2 diagram) described in NASAs Systems Engineering Handbook are utilized early in the design phase to identify potential conflicts in the mechanical and electrical interfaces. A novel subsystem level flowdown, which transcribes the system level requirements into identifiable CubeSat subsystems, (i.e., building blocks) is described. Utilizing this approach yields full traceability from mission concept to subsystem component to flight software. Additionally, the approach facilitates the estimation of the mission overhead in terms of power, telemetry, and computation associated with each component, interface, and task.

A Bayesian Hidden Markov Model-based approach for anomaly detection in electronic systems

Abstract: Early detection of anomalies in any system or component prevents impending failures and enhances performance and availability. The complex architecture of electronics, the interdependency of component functionalities, and the miniaturization of most electronic systems make it difficult to detect and analyze anomalous behaviors. A Hidden Markov Model-based classification technique determines unobservable hidden behaviors of complex and remotely inaccessible electronic systems using observable signals. This paper presents a data-driven approach for anomaly detection in electronic systems based on a Bayesian Hidden Markov Model classification technique. The posterior parameters of the Hidden Markov Models are estimated using the conjugate prior method. An application of the developed Bayesian Hidden Markov Model-based anomaly detection approach is presented for detecting anomalous behavior in Insulated Gate Bipolar Transistors using experimental data. The detection results illustrate that the developed anomaly detection approach can help detect anomalous behaviors in electronic systems, which can help prevent system downtime and catastrophic failures.

Mars Organic Molecule Analyzer (MOMA) mass spectrometer for ExoMars 2018 and beyond

Abstract: The 2018 joint ESA-Roscosmos ExoMars rover mission will seek the signs of past or present life in the near-surface environment of Mars. The rover will obtain samples from as deep as two meters beneath the surface and deliver them to an onboard analytical laboratory for detailed examination. The Mars Organic Molecule Analyzer (MOMA) investigation forms a core part of the sample analysis capability of ExoMars. Its top objective is to address the main “life signs” goal of the mission through detailed chemical analysis of the acquired samples. MOMA characterizes organic compounds in the samples with a novel dual ion source ion trap mass spectrometer (ITMS). The ITMS supports both pyrolysis-gas chromatography (pyr-GC) and Mars ambient laser desorption/ionization (LDI) analyses in an extremely compact package. Combined with the unprecedented depth sampling capability of ExoMars, MOMA affords a broad and powerful search for organics over a range of preservational environments, volatility, and molecular weight.

The NASA EV-2 Cyclone Global Navigation Satellite System (CYGNSS) mission

Abstract: The NASA EV-2 Cyclone Global Navigation Satellite System (CYGNSS) is a spaceborne mission focused on tropical cyclone (TC) inner core process studies. CYGNSS attempts to resolve the principle deficiencies with current TC intensity forecasts, which lies in inadequate observations and modeling of the inner core. The inadequacy in observations results from two causes: 1) Much of the inner core ocean surface is obscured from conventional remote sensing instruments by intense precipitation in the eye wall and inner rain bands. 2) The rapidly evolving (genesis and intensification) stages of the TC life cycle are poorly sampled in time by conventional polar-orbiting, wide-swath surface wind imagers. CYGNSS is specifically designed to address these two limitations by combining the all-weather performance of GNSS bistatic ocean surface scatterometry with the sampling properties of a constellation of satellites.

Predicted reliability of aerospace electronics: Application of two advanced probabilistic concepts

Abstract: Two advanced probabilistic design-for-reliability (PDfR) concepts are addressed and discussed in application to the prediction, quantification and assurance of the aerospace electronics reliability: 1) Boltzmann-Arrhenius-Zhurkov (BAZ) model, which is an extension of the currently widely used Arrhenius model and, in combination with the exponential law of reliability, enables one to obtain a simple, easy-to-use and physically meaningful formula for the evaluation of the probability of failure (PoF) of a material or a device after the given time in operation at the given temperature and under the given stress (not necessarily mechanical), and 2) Extreme Value Distribution (EVD) technique that can be used to assess the number of repetitive loadings that result in the material/device degradation and eventually lead to its failure by closing, in a step-wise fashion, the gap between the bearing capacity (stress-free activation energy) of the material or the device and the demand (loading).