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NASA NTRS2016

Closed Loop Control Compact Exercise Device for Use on MPCV

Long duration space travel to Mars or to an asteroid will expose astronauts to extended periods of reduced gravity. To combat spaceflight physiological deconditioning, astronauts will use resistive and aerobic exercise regimens for the duration of the space flight to minimize the loss of bone density, muscle mass and aerobic capacity that occurs during exposure to a reduced gravity environment. Unlike the International Space Station (ISS), the mass and volume available for an exercise device in the next generation of spacecraft is limited. Therefore, compact exercise device prototypes are being developed for human in the loop evaluations. The NASA Human Research Program (HRP) is managing Advanced Exercise Concepts (AEC) requirements development and candidate technology maturation for all exploration mission profiles from Multi-Purpose Crew Vehicle (MPCV) exploration missions (e.g., EM-2, up to 21 day) to Mars Transit (up to 1000 day) missions. Numerous technologies have been considered and evaluated against HRP-approved functional requirements and include flywheel, pneumatic and closed-loop microprocessor-controlled motor driven power plants. Motor driven technologies offer excellent torque density and load accuracy characteristics as well as the ability to create custom mechanical impedance (the dynamic relationship between force and velocity) and custom load versus position exercise algorithms. Further, closed-loop motor-driven technologies offer the ability to monitor exercise dose parameters and adapt to the needs of the crewmember for real time optimization of exercise prescriptions. A simple proportional-integral-derivative (PID) controller is demonstrated in a prototype motor driven exercise device with comparison to resistive static and dynamic load set points and aerobic work rate targets. The resistive load term in the algorithm includes a constant force component (Fcmg) as well as inertial component (Fima) and a discussion of system tuning is presented in terms of addressing key functional requirements and human interfaces. The device aerobic modality is modelled as a rowing exercise using ground data sets obtained from Concept 2 rowers as well as competitive rowing1. A discussion of software and electronic implementations are presented which demonstrate unique approaches to meeting the constrained mass, volume and power requirements of the MPCV. . In addition to utilizing traditional PID control, controllers utilizing state feedback with gains solved using a Linear Quadratic Regulator will be developed. Controllability and observability will be utilized to investigate the need for state measurement in the design. As the control system directly interacts with human test subjects, robust methods such as H-infinity are also being investigated.1. Kleshnev V. Biomechanics. In: Rowing, Handbook of Sports Medicine and Science. ed. by Secher N., Voliantis S. IOC Medical Commission, Blackwell Pub. pp. 22-34, 2007

microgravity↗
NASA NTRS2010

Statistical Attitude Determination

All spacecraft require attitude determination at some level of accuracy. This can be a very coarse requirement of tens of degrees, in order to point solar arrays at the sun, or a very fine requirement in the milliarcsecond range, as required by Hubble Space Telescope. A toolbox of attitude determination methods, applicable across this wide range, has been developed over the years. There have been many advances in the thirty years since the publication of Reference, but the fundamentals remain the same. One significant change is that onboard attitude determination has largely superseded ground-based attitude determination, due to the greatly increased power of onboard computers. The availability of relatively inexpensive radiation-hardened microprocessors has led to the development of "smart" sensors, with autonomous star trackers being the first spacecraft application. Another new development is attitude determination using interferometry of radio signals from the Global Positioning System (GPS) constellation. This article reviews both the classic material and these newer developments at approximately the level of, with emphasis on. methods suitable for use onboard a spacecraft. We discuss both "single frame" methods that are based on measurements taken at a single point in time, and sequential methods that use information about spacecraft dynamics to combine the information from a time series of measurements.

Markley, F. Landis↗
NASA NTRS2010

Physical and Electrical Characterization of Aluminum Polymer Capacitors

Conductive polymer aluminum capacitor (PA capacitor) is an evolution of traditional wet electrolyte aluminum capacitors by replacing liquid electrolyte with a solid, highly conductive polymer. On the other hand, the cathode construction in polymer aluminum capacitors with coating of carbon and silver epoxy for terminal connection is more like a combination of the technique that solid tantalum capacitor utilizes. This evolution and combination result in the development of several competing capacitor construction technologies in manufacturing polymer aluminum capacitors. The driving force of this research on characterization of polymer aluminum capacitors is the rapid progress in IC technology. With the microprocessor speeds exceeding a gigahertz and CPU current demands of 80 amps and more, the demand for capacitors with higher peak current and faster repetition rates bring conducting polymer capacitors to the center o( focus. This is because this type of capacitors has been known for its ultra-low ESR and high capacitance. Polymer aluminum capacitors from several manufacturers with various combinations of capacitance, rated voltage, and ESR values were obtained and tested. The construction analysis of the capacitors revealed three different constructions: conventional rolled foil, the multilayer stacking V-shape, and a dual-layer sandwich structure. The capacitor structure and its impact on the electrical characteristics has been revealed and evaluated. A destructive test with massive current over stress to fail the polymer aluminum capacitors reveals that all polymer aluminum capacitors failed in a benign mode without ignition, combustion, or any other catastrophic failures. The extraordinary low ESR (as low as 3 mOMEGA), superior frequency independence reported for polymer aluminum capacitors have been confirmed. For the applications of polymer aluminum capacitors in space programs, a thermal vacuum cycle test was performed. The results, as expected, show no impact on the electrical characteristics of the capacitors. The breakdown voltage of polymer capacitors has been evaluated using a steady step surge test. Initial results show the uniform distribution in the breakdown voltage for polymer aluminum capacitors. Polymer aluminum capacitors with a combination of very high capacitance, extraordinary low ESR, excellent frequency stability, and non-ignite benign failure mode make it a niche fit in space applications for both today and future. Polymer capacitors are apparently also the best substitutes of the currently used MnO2-based tantalum capacitors in the low voltage range. However, some critical aspects are still to be addressed in the next phase of the investigation for PA capacitors. These include the long term reliability test of 125 C dry life and 85 C/85%RH humidity, the failure mechanism and de-rating, the radiation tolerance, and the high temperature performance. All of the above requires the continuous NEPP funding and support.

Liu, David (Donghang)↗
NASA NTRS2018

Body of Knowledge for Graphics Processing Units (GPUs)

Graphics Processing Units (GPU) have emerged as a proven technology that enables high performance computing and parallel processing in a small form factor. GPUs enhance the traditional computer paradigm by permitting acceleration of complex mathematics and providing the capability to perform weighted calculations, such as those in artificial intelligence systems. Despite the performance enhancements provided by this type of microprocessor, there exist tradeoffs in regards to reliability and radiation susceptibility, which may impact mission success. This report provides an insight into GPU architecture and its potential applications in space and other similar markets. It also discusses reliability, qualification, and radiation considerations for testing GPUs.

NASA Electronic Parts and Packaging (NEPP) Program↗
NASA NTRS2017

CHOMPTT (CubeSat Handling of Multisystem Precision Timing Transfer): From Concept to Launch Pad

Here we present the evolution of a student satellite mission: CHOMPTT (CubeSat Handling of Multisystem Precision Time Transfer), from its original concept as a candidate for the University NanoSatellite Program 8 (UNP8), to a spacecraft ready for launch in Fall of 2017 on ELaNa XIX (Educational Launch of Nanosatellites). The 3U CubeSat houses a 1 kg, 1U OPTI (Optical Precision Timing Instrument) payload, designed and built at the University of Florida, and a 1.5U EDSNNODeS-derived bus from NASA Ames Research Center. The OPTI payload comprises of: 1) a supervisor board that handles payload data, power regulation, and mode settings, 2) an optics assembly of six 1 cm retroreflectors and four laser beacon diodes for ground-tracking; and 3) two fully redundant timing channels, each consisting of: a chip-scale atomic clock, a microprocessor with clock counter, a picosecond event timer, and an avalanche photodetector (APD) with band-pass filter. Several iterations of OPTI have been developed, tested, and designed to achieve its current functionality and design a laboratory breadboard design, a 1.5U high altitude balloon design, engineering unit design, and its current flight unit design. In-lab testing of the current OPTI design indicates a short-term precision of 100 ps, equivalent to a range accuracy of 3 cm necessary to achieve our primary objective of 200 ps time transfer error, and a long-term timing accuracy of 20 ns over one orbit (1.5 hours). After the spacecraft reaches its nominal 500 km orbit at a 85 degree inclination, an experimental laser ranging facility at Kennedy Space Center in Florida, will track and emit 1064 nm nanosecond optical pulses at the CHOMPTT spacecraft. The laser pulses will then reflect off the retroreflector array mounted on the nadir face of CHOMPTT, and return the pulse to the laser ranging facility where the laser ranging facility will record the round-trip duration of the laser pulses. At the same time the pulse arrives at the spacecraft and is reflected by the array, an APD will record the arrival time of the pulses at the nanosatellite. By comparing the arrival of the pulse at the CubeSat and the duration of the round-trip of the laser pulse, the clock discrepancy between the ground and CubeSat atomic clocks can be determined, in addition to the CubeSats range from the facility. The design and verification of the flight version of CHOMPTT will be reviewed and an overview of the lifetime development and progression of CHOMPTT from the inception to launch pad will be presented.

CHOMPTT↗
NASA NTRS2016

M2020/MSL: TDS (Terminal Descent Sensor) DEA (Digital Electronics Assembly)

TDS is the radar used in MSL mission to land Curiosity rover on Mars. TDS will be used again in M2020 mission. DEA is the brain of the TDS where it serves as the controller and digital signal processor. The DEA commands TDS to cycle through the antenna beams making measurements using one of the 6 antenna beams at a time. DEA uses beam sequences and parameter tables to generate measurements. The most important measurements are velocity and range that are used to guide the landing of Curiosity rover. DEA performs these measurement tasks using radar signal processing FPGA firmware and radar microprocessor ‘s hardware and software.

Ashtijou, Mohammad↗
NASA NTRS2020

High Temperature Electronics for Venus Surface Applications: A Summary of Recent Technical Advances

This white paper has a technical focus meant to provide background to those unfamiliar with the challenges of high temperature electronics, and an understanding of why new surface mission concepts are now viable for Venus and other applications. It describes that, for the first time, high temperature electronics have been developed to enable a paradigm change in extended duration Venus surface exploration. This white paper concentrates on the advances made in Silicon Carbide (SiC) integrated circuit (IC) electronics that have matured to a state where a simple long-life scientific probe is feasible for Venus surface operations. These electronics have been demonstrated for more than a year at 500˚C, 60 days in high-fidelity simulated Venus surface conditions chamber, and have been integrated and demonstrated with prototype long-lived scientific observation sensor technology. Continued maturation of these needed high temperature electronics and sensors is ongoing in the Long-Lived In-Situ Solar System Explorer (LLISSE) project to provide an operational system including sensor control and operation, signal processing, power management, and communications in the early part of the 2020’s. A key focus of this work includes increasing the complexity and decreasing the power consumption of the ICs which will pave the way to enhanced capabilities, such as long-duration Venus seismic measurements. Other IC development efforts include high temperature memory, terrestrial based characterization of volcanic magma, and development of a simple microprocessor. This electronics has also shown to have exceptionally high radiation tolerance, and thus have relevance for a broad range of solar system exploration. Although presently at the level of complexity of 1970-1980 silicon-based electronics, such electronics can enable breakthroughs in Venus planetary exploration akin to 1970s-launched planetary exploration successes (such as Viking and Voyager).

High temperature Electronics↗
NASA NTRSDate not supplied

Automating the Study of Microbial Adaptation Dynamics on and off the ISS

The International Space Station (ISS) not only serves as a unique environment for humans, but also the microorganisms that join alongside. Many microbes present on the spacecraft arrive via humans, and as they interact with different surfaces they begin to inhabit those locations. Much like how human health has shown to be impacted by these extreme environments, microbial viability and response to stress also changes. Experimental evolution (EE) can aid in studying how microbes’ growth and activity changes within the ISS environments by applying controlled stressors to microbial cultures and monitoring their response over generations. EE studies are commonly done manually in laboratories, but, with multiple environmental variables to measure and adjust, it becomes highly labor-intensive, prone to human error, and challenging to scale. A multipurpose automated EE system named the AADEC has been developed to address these problems. This system integrates multiple sensors into a single fluidic chamber using UV-C flux, temperature, and media composition as stressors. AADEC contains five sensors: oxidation-reduction potential, electrical conductivity, pH, dissolved oxygen, and optical density. On their own, each is able to provide certain information on growth rate or metabolism; together, they show in detail how stressors affect life. AADEC studies can be conducted on Earth and repeated aboard the ISS to see how behavior changes when exposed to space mission stressors such as microgravity and radiation. AADEC’s auxiliary systems include peristaltic pumps for media exchange, magnetic rods for agitation, and a Raspberry Pi microprocessor to monitor, store, and adjust stressor levels real-time. This allows researchers to gather information within rapid generations, data and accuracy which is challenging to achieve through manual studies. With further miniaturization and automation, such as a more robust single-piece fluidics card, AADEC has the potential to be developed as a spacecraft payload. Support: NASA Ames CIF Award

Automating↗
NASA NTRS1999

A Low-Power High-Speed Smart Sensor Design for Space Exploration Missions

In this paper, an ultra-fast low-power smart vision system-on-a-chip design is proposed to provide effective solutions for real time machine vision applications by taking advantages of advances in integrated sensing/processing designs, electronic neural networks, advanced microprocessors, and sub-micron VLSI systemns-on-a-chip (SOAC) technology.

space↗
NASA NTRS1997

Realization of a Faster, Cheaper, Better Star Tracker for the New Millennium

The first Danish satellite, إrsted, will be launched in August of 1997. The scientific objective of إrsted is to perform a precision mapping of the Earth's magnetic field. Attitude data for the payload and the satellite are provided by the Advanced Stellar Compass (ASC) star tracker. The ASC consists of a CCD star camera and a capable microprocessor which operates by comparing the star image frames taken by the camera to its internal star catalogs.

star↗
NASA NTRS2017

Thermal cycling testing to failure of a ceramic column grid array package for space applications

Ceramic column grid array (CCGA) packages have been used increasingly in logic and microprocessor functions, telecommunications, flight avionics boards, payload electronics boards, engineering navigational and science cameras, electronic assemblies, and other applications, because of their inherent advantages such as high electrical interconnect density, very good thermal and electrical performance, and compatibility with standard surface-mount technology (SMT) packaging assembly processes. Because these advanced electronic packages tend to have less solder-joint strain-relief than do leaded flat-pack electronic packages, the reliability of CCGA packages in challenging thermal environments is a very important consideration for their short- and long-term use in JPL-NASA space missions. In this study, we assembled daisy chains of polyimide printed wiring boards from CCGA-interconnect packages, inspected the boards nondestructively, and then subjected them to thermal cycling to assess their reliability in thermal environments from +125°C to -40°C±25°C. The test hardware consists of a CCGA 1752 package (CN version). The package was divided into four daisy-chained sections that were electrically monitored for their continuity during thermal cycling. The CCGA 1752 package is roughly 45 mm × 45 mm with a 42-mm × 42-mm array of 80%/20% Pb/Sn columns on a 1.00-mm pitch. The resistance of the daisy-chained CCGA interconnects was continuously monitored during thermal cycling in a gaseous nitrogen environment. Electrical continuity resistance measurements as a function of thermal cycling are reported here; tests to date have shown significant change to an open circuit in daisy-chain resistance as a function of thermal cycling. The change in interconnect resistance becomes increasingly noticeable with increasing number of thermal cycles. This paper describes the experimental thermal-cycling test results of CCGA 1752 package reliability testing under an extremely wide temperature range. The first failure was observed at 1479th thermal cycle. We report the thermal-cycle reliability test data for ~2500 thermal cycles.

Ramesham, Rajeshuni↗
NASA NTRSDate not supplied

Open-source Wireless Sensor Network (Wi-Se Net) for Flexible Deployment

Wireless sensors, especially if battery powered, have a number of advantages over wired sensors for flexible or temporary diagnostic deployment in a field or lab setting. Recent advances in wireless technology and microprocessor boards have produced a variety of inexpensive off-the shelf chips which can communicate wirelessly with simple protocols. This paper describes the design and implementation of a highly customizable wireless sensor network (called WiSe Net) using inexpensive open-source hardware components as wireless nodes. These wireless sensor nodes can transmit data at a rate <250 Hz, can be battery powered, and have a small footprint (2x5 cm). In addition, a preliminary over-the-air programming system was developed to allow for simple wireless configuration when active. The network performance was demonstrated by taking distributed and electrically isolated temperature measurements on a high-voltage lab apparatus. Although this test case is in a laboratory setting, this network architecture could be easily repurposed for various other forms of monitoring

Wireless Sensor Network↗
NASA NTRSDate not supplied

Open-source Wireless Sensor Network (Wi-Se Net) for Flexible Deployment

Wireless sensors, especially if battery powered, have a number of advantages over wired sensors for flexible or temporary diagnostic deployment in a field or lab setting. Recent advances in wireless technology and microprocessor boards have produced a variety of inexpensive off-the shelf chips which can communicate wirelessly with simple protocols. This paper describes the design and implementation of a highly customizable wireless sensor network (called Wi-Se Net) using inexpensive open-source hardware components as wireless nodes. These wireless sensor nodes can transmit data at a rate <250 Hz, can be battery powered, and have a small footprint (2x5 cm). In addition, a preliminary over-the-air programming system was developed to allow for simple wireless configuration when active. The network performance was demonstrated by taking distributed and electrically isolated temperature measurements on a high-voltage lab apparatus. Although this test case is in a laboratory setting, this network architecture could be easily repurposed for various other forms of monitoring.

Wireless Sensor Network↗
NASA NTRSDate not supplied

Open-source Wireless Sensor Network (Wi-Se Net) for Flexible Deployment

Wireless sensors, especially if battery powered, have a number of advantages over wired sensors for flexible or temporary diagnostic deployment in a field or lab setting. Recent advances in wireless technology and microprocessor boards have produced a variety of inexpensive off-the shelf chips which can communicate wirelessly with simple protocols. This paper describes the design and implementation of a highly customizable wireless sensor network (called WiSe Net) using inexpensive open-source hardware components as wireless nodes. These wireless sensor nodes can transmit data at a rate <250 Hz, can be battery powered, and have a small footprint (2x5 cm). In addition, a preliminary over-the-air programming system was developed to allow for simple wireless configuration when active. The network performance was demonstrated by taking distributed and electrically isolated temperature measurements on a high-voltage lab apparatus. Although this test case is in a laboratory setting, this network architecture could be easily repurposed for various other forms of monitoring.

Wireless Sensor Network↗
NASA NTRSDate not supplied

Recent Progress in Extreme Environment Durable SiC JFET-R Integrated Circuit Technology

This work updates recent progress made by NASA Glenn Research Center on further advancement of its uniquely durable silicon carbide junction field effect transistor and resistor (SiC JFET-R) integrated circuit (IC) technology since HiTEC 2021. Key fabrication process improvements compared to earlier NASA Glenn IC prototype runs have been ascertained via extensive “back end of line” (BEOL) processing experiments conducted on practice wafers over the past two years. The resulting changes to the BEOL process flow employed in the fabrication of “Generation 12” SiC JFET-R wafers are described. The NASA Glenn SiC JFET-R IC prototype “Generation 12” chipset design realizes significantly higher complexity digital and analog integrated ICs aimed at flexibly implementing a broad variety of mission-enabling extreme-environment electronics demonstrations. SPICE simulations have verified circuit designs ranging from simple amplification of analog sensor signals up through long-duration Venus lander operations and microprocessor-based of electric motor drive.

Silicon Carbide↗
NASA NTRSDate not supplied

Recent Progress in Extreme Environment Durable SiC JFET-R Integrated Circuit Technology

This work updates recent progress made by NASA Glenn Research Center on further advancement of its uniquely durable silicon carbide junction field effect transistor and resistor (SiC JFET-R) integrated circuit (IC) technology since HiTEC 2021. Key fabrication process improvements compared to earlier NASA Glenn IC prototype runs have been ascertained via extensive “back end of line” (BEOL) processing experiments conducted on practice wafers over the past two years. The resulting changes to the BEOL process flow employed in the fabrication of “Generation 12” SiC JFET-R wafers are described. The NASA Glenn SiC JFET-R IC prototype “Generation 12” chipset design realizes significantly higher complexity digital and analog integrated ICs aimed at flexibly implementing a broad variety of mission-enabling extreme-environment electronics demonstrations. SPICE simulations have verified circuit designs ranging from simple amplification of analog sensor signals up through long-duration Venus lander operations and microprocessor-based of electric motor drive.

Silicon Carbide↗