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NASA NTRS2016

Heatshield for Extreme Entry Environment Technology (HEEET) Development Status

The Heat shield for Extreme Entry Environment Technology (HEEET) Project is a NASA STMD and SMD co-funded effort. The goal is to develop and mission infuse a new ablative Thermal Protection System that can withstand extreme entry. It is targeted to support NASAs high priority missions, as defined in the latest decadal survey, to destinations such as Venus and Saturn in-situ robotic science missions. Entry into these planetary atmospheres results in extreme heating. The entry peak heat-flux and associated pressure are estimated to be between one and two orders of magnitude higher than those experienced by Mars Science Laboratory or Lunar return missions. In the recent New Frontiers community announcement NASA has indicated that it is considering providing an increase to the PI managed mission cost (PIMMC) for investigations utilizing the Heat Shield for Extreme Entry Environment Technology (HEEET) and in addition, NASA is considering limiting the risk assessment to only their accommodation on the spacecraft and the mission environment. The HEEET ablative TPS utilizes 3D weaving technology to manufacture a dual layer material architecture. The 3-D weaving allows for flat panels to be woven. The dual layer consists of a top layer designed to withstand the extreme external environment while the inner or insulating layer by design, is designed to achieve low thermal conductivity, and it keeps the heat from conducting towards the structure underneath. Both arc jet testing combined with material properties have been used to develop thermal response models that allows for comparison of performance with heritage carbon phenolic. A 50 mass efficiency is achieved by the dual layer construct compared to carbon phenolic for a broad range of missions both to Saturn and Venus. The 3-D woven flat preforms are molded to achieve the shape as they are compliant and then resin infusion with curing forms a rigid panels. These panels are then bonded on to the aeroshell structure. Gaps exist between the panels and these gaps have to be filled with seams. The seam material then has to be bonded on to adjacent panels and also to the structure. The heat-shield assembly is shown in Figure 1. One of the significant challenges we have overcome recently is the design, development and testing of the seam. HEEET material development and the seam concept development have utilized some of the unique test capabilities available in the US. The various test facilities utilized in thermal testing along with the entry environment for Saturn and Venus missions are shown in Figure 2. The HEEET project is currently in its 3rd year of a four-year development. Figure 3 illustrates the key accomplishments to date and the challenges yet to be overcome before the technology is ready for mission infusion. This proposed presentation will cover both progress that has been made in the HEEET project and also the challenges to be overcome that is highlighted in Figure 3. Objective of the HEEET project is to mature the system in time to support the next New Frontiers opportunity and we believe we are well along the way to mission infuse HEEET.

Thermal Protection System↗

NASA NTRS2016

Heat-shield for Extreme Entry Environment Technology (HEEET) Development Status

The Heat shield for Extreme Entry Environment Technology (HEEET) Project is a NASA STMD and SMD co-funded effort. The goal is to develop and mission infuse a new ablative Thermal Protection System that can withstand extreme entry. It is targeted to support NASA's high priority missions, as defined in the latest decadal survey, to destinations such as Venus and Saturn in-situ robotic science missions. Entry into these planetary atmospheres results in extreme heating. The entry peak heat-flux and associated pressure are estimated to be between one and two orders of magnitude higher than those experienced by Mars Science Laboratory or Lunar return missions. In the recent New Frontiers community announcement NASA has indicated that it is considering providing an increase to the PI managed mission cost (PIMMC) for investigations utilizing the Heat Shield for Extreme Entry Environment Technology (HEEET) and in addition, NASA is considering limiting the risk assessment to only their accommodation on the spacecraft and the mission environment. The HEEET ablative TPS utilizes 3D weaving technology to manufacture a dual layer material architecture. The 3-D weaving allows for flat panels to be woven. The dual layer consists of a top layer designed to withstand the extreme external environment while the inner or insulating layer by design, is designed to achieve low thermal conductivity, and it keeps the heat from conducting towards the structure underneath. Both arc jet testing combined with material properties have been used to develop thermal response models that allows for comparison of performance with heritage carbon phenolic. A 50% mass efficiency is achieved by the dual layer construct compared to carbon phenolic for a broad range of missions both to Saturn and Venus. The 3-D woven flat preforms are molded to achieve the shape as they are compliant and then resin infusion with curing forms a rigid panels. These panels are then bonded on to the aeroshell structure. Gaps exist between the panels and these gaps have to be filled with seams. The seam material then has to be bonded on to adjacent panels and also to the structure. The heat-shield assembly is shown in Figure 1. One of the significant challenges we have overcome recently is the design, development and testing of the seam. HEEET material development and the seam concept development have utilized some of the unique test capabilities available in the US. The various test facilities utilized in thermal testing along with the entry environment for Saturn and Venus missions are shown in Figure 2. The HEEET project is currently in it's 3rd year of a four-year development. Figure 3 illustrates the key accomplishments to-date and the challenges yet to be overcome before the technology is ready for mission infusion. This proposed presentation will cover both progress that has been made in the HEEET project and also the challenges to be overcome that is highlighted in Figure 3. Objective of the HEEET project is to mature the system in time to support the next New Frontiers opportunity and we believe we are well along the way to mission infuse HEEET.

TPS↗

NASA NTRS2017

Near Earth Asteroid Scout Solar Sail Engineering Development Unit Test Suite

The Near Earth Asteroid (NEA) Scout project is a 6U reconnaissance mission to investigate a near Earth asteroid utilizing an 86m(sub 2) solar sail as the primary propulsion system. This will be the largest solar sail NASA has launched to date. NEA Scout is currently manifested on the maiden voyage of the Space Launch System in 2018. In development of the solar sail subsystem, design challenges were identified and investigated for packaging within a 6U form factor and deployment in cis-lunar space. Analysis was able to capture understanding of thermal, stress, and dynamics of the stowed system as well as mature an integrated sail membrane model for deployed flight dynamics. Full scale system testing on the ground is the optimal way to demonstrate system robustness, repeatability, and overall performance on a compressed flight schedule. To physically test the system, the team developed a flight sized engineering development unit with design features as close to flight as possible. The test suite included ascent vent, random vibration, functional deployments, thermal vacuum, and full sail deployments. All of these tests contributed towards development of the final flight unit. This paper will address several of the design challenges and lessons learned from the NEA Scout solar sail subsystem engineering development unit. Testing on the component level all the way to the integrated subsystem level. From optical properties of the sail material to fold and spooling the single sail, the team has developed a robust deployment system for the solar sail. The team completed several deployments of the sail system in preparation for flight at half scale (4m) and full scale (6.8m): boom only, half scale sail deployment, and full scale sail deployment. This paper will also address expected and received test results from ascent vent, random vibration, and deployment tests.

Lockett, Tiffany Russell↗

NASA NTRS2016

NASA Planetary Science Division's Instrument Development Programs, PICASSO and MatISSE

The Planetary Science Division (PSD) has combined several legacy instrument development programs into just two. The Planetary Instrument Concepts Advancing Solar System Observations (PICASSO) program funds the development of low TRL instruments and components. The Maturation of Instruments for Solar System Observations (MatISSE) program funds the development of instruments in the mid-TRL range. The strategy of PSD instrument development is to develop instruments from PICASSO to MatISSE to proposing for mission development.

Instruments↗

NASA NTRS2017

Development and Testing of Carbon-Carbon Nozzle Extensions for Upper Stage Liquid Rocket Engines

Carbon-carbon (C-C) composite nozzle extensions are of interest for use on a variety of launch vehicle upper stage engines and in-space propulsion systems. The C-C nozzle extension technology and test capabilities being developed are intended to support National Aeronautics and Space Administration (NASA) and Department of Defense (DOD) requirements, as well as those of the broader Commercial Space industry. For NASA, C-C nozzle extension technology development primarily supports the NASA Space Launch System (SLS) and NASA's Commercial Space partners. Marshall Space Flight Center (MSFC) efforts are aimed at both (a) further developing the technology and databases needed to enable the use of composite nozzle extensions on cryogenic upper stage engines, and (b) developing and demonstrating low-cost capabilities for testing and qualifying composite nozzle extensions. Recent, on-going, and potential future work supporting NASA, DOD, and Commercial Space needs will be discussed. Information to be presented will include (a) recent and on-going mechanical, thermal, and hot-fire testing, as well as (b) potential future efforts to further develop and qualify domestic C-C nozzle extension solutions for the various upper stage engines under development.

Valentine, Peter G.↗

NASA NTRS2018

Iodine Hall-Effect Electric Propulsion System Research, Development, and System Durability Demonstration

This paper reviews recent iodine electric propulsion research and development activities at the NASA Glenn Research Center (GRC). Activities included (i) investigation of the iodine compatibility of BaO-CaO-Al2O3 impregnated tungsten hollow cathodes based on a flight heritage design, (ii) investigation of the iodine compatibility of a handful of materials common to propulsion systems, spacecraft, and ground test facilities, (iii) development of reliable iodine feed system technologies, (iv) implementation of test facility improvements in an attempt to mitigate iodine associated negative impacts, and culminated in (v) an 1,174-hour hybrid iodine-xenon propulsion system durability demonstration (iodine fed Hall-effect thruster with xenon fed cathode). Each of the activities resulted in extensive insights that shall inform future iodine electric propulsion developments. While reliable operation of a BaO-CaO-Al2O3 impregnated tungsten hollow cathode on iodine vapor was not achieved, long-term operation on xenon gas in proximity to an iodine fed thruster was demonstrated without any measurable degradation or cross-contamination of the cathode. Furthermore, iodine material corrosion investigations conducted at 300degC over 5, 15, and 30 days showed significant deterioration of all materials evaluated, although the same materials with a silicon coating proved nearly impervious to iodine so long as the coating was not mechanically damaged. Finally, the 1,174-hour durability test demonstration showed that (i) iodine feed system technologies developed at GRC delivered well-regulated uninterrupted propellant, (ii) implementation of appropriate facility improvements and procedures can limit negative impacts of iodine on test hardware and ground support equipment, although facility challenges with iodine are extensive, and (iii) a Hall-effect thruster operates with similar performance whether employing iodine or xenon propellant over long durations. The work was motivated by strong government and commercial interest in the growing capabilities of small-spacecraft (<500 kg), in combination with interest for denser low-power, high delta-v in-space propulsion systems. This work adds to a growing body of research and development efforts aimed at addressing the many anticipated challenges of implementing iodine as an in-space propellant. This work was conducted under the Advanced In-Space Propulsion (AISP) project funded through the Game Changing Development (GCD) program within NASA's Science Technology Mission Directorate (STMD).

Benavides, Gabriel F.↗

NASA NTRS2018

Iodine Hall-Effect Electric Propulsion System Research, Development, and System Durability Demonstration

This paper reviews recent iodine electric propulsion research and development activities at the NASA Glenn Research Center (GRC). Activities included (i) investigation of the iodine compatibility of BaO-CaO-Al2O3 impregnated tungsten hollow cathodes based on a flight heritage design, (ii) investigation of the iodine compatibility of a handful of materials common to propulsion systems, spacecraft, and ground test facilities, (iii) development of reliable iodine feed system technologies, (iv) implementation of test facility improvements in an attempt to mitigate iodine associated negative impacts, and culminated in (v) an 1,174-hour hybrid iodine-xenon propulsion system durability demonstration (iodine fed Hall-effect thruster with xenon fed cathode). Each of the activities resulted in extensive insights that shall inform future iodine electric propulsion developments. While reliable operation of a BaO-CaO-Al2O3 impregnated tungsten hollow cathode on iodine vapor was not achieved, long-term operation on xenon gas in proximity to an iodine fed thruster was demonstrated without any measurable degradation or cross-contamination of the cathode. Furthermore, iodine material corrosion investigations conducted at 300 C over 5, 15, and 30 days showed significant deterioration of all materials evaluated, although the same materials with a silicon coating proved nearly impervious to iodine so long as the coating was not mechanically damaged. Finally, the 1,174-hour durability test demonstration showed that (i) iodine feed system technologies developed at GRC delivered well-regulated uninterrupted propellant, (ii) implementation of appropriate facility improvements and procedures can limit negative impacts of iodine on test hardware and ground support equipment, although facility challenges with iodine are extensive, and (iii) a Hall-effect thruster operates with similar performance whether employing iodine or xenon propellant over long durations. The work was motivated by strong government and commercial interest in the growing capabilities of small-spacecraft (<500 kg), in combination with interest for denser low-power, high delta-v in-space propulsion systems. This work adds to a growing body of research and development efforts aimed at addressing the many anticipated challenges of implementing iodine as an in-space propellant. This work was conducted under the Advanced In-Space Propulsion (AISP) project funded through the Game Changing Development (GCD) program within NASA's Science Technology Mission Directorate (STMD).

Benavides, Gabriel F.↗

NASA NTRS2018

Iodine Hall-Effect Electric Propulsion System Research, Development, and System Durability Demonstration

This paper reviews recent iodine electric propulsion research and development activities at the NASA Glenn Research Center (GRC). Activities included (i) investigation of the iodine compatibility of BaO-CaO-Al2O3 impregnated tungsten hollow cathodes based on a flight heritage design, (ii) investigation of the iodine compatibility of a handful of materials common to propulsion systems, spacecraft, and ground test facilities, (iii) development of reliable iodine feed system technologies, (iv) implementation of test facility improvements in an attempt to mitigate iodine associated negative impacts, and culminated in (v) an 1,174-hour hybrid iodine-xenon propulsion system durability demonstration (iodine fed Hall-effect thruster with xenon fed cathode). Each of the activities resulted in extensive insights that shall informfuture iodine electric propulsion developments. While reliable operation of a BaO-CaO-Al2O3 impregnated tungsten hollow cathode on iodine vapor was not achieved, long-term operation on xenon gas in proximity to an iodine fed thruster was demonstrated without any measurable degradation or cross-contamination of the cathode. Furthermore, iodine material corrosion investigations conducted at 300 degrees C over 5, 15, and 30 days showed significant deterioration of all materials evaluated, although the same materials with a silicon coating proved nearly impervious to iodine so long as the coating was not mechanically damaged. Finally, the 1,174-hour durability test demonstration showed that (i) iodine feed system technologies developed at GRC delivered well-regulated uninterrupted propellant, (ii) implementation of appropriate facility improvements and procedures can limit negative impacts of iodine on test hardware and ground support equipment, although facility challenges with iodine are extensive, and (iii) a Hall-effect thruster operates with similar performance whether employing iodine or xenon propellant over long durations. The work was motivated by strong government and commercial interest in the growing capabilities of small-spacecraft (<500 kg), in combination with interest for denser low-power, high delta-v in-space propulsion systems. This work adds to a growing body of research and development efforts aimed at addressing the many anticipated challenges of implementing iodine as an in-space propellant. This work was conducted under the Advanced In-Space Propulsion (AISP) project funded through the Game Changing Development (GCD) program within NASA's Science Technology Mission Directorate (STMD).

Benavides, Gabriel F.↗

NASA NTRS2018

The Disruptive Technology That is Additive Construction: System Development Lessons Learned for Terrestrial and Planetary Applications

Disruptive technologies are unique in that they spawn other new technologies and applications as they grow. These activities are usually preceded by the question, "What If?" For example, "What if we could use an emerging technology and in-situ materials to promote exploration on the Moon or Mars, and then use that same technology to keep our troops out of harm's way and/or help the worlds' homeless?" This question allows us to flip the mindset of "how can people create more valuable innovation?" to "how can innovation create more valuable people?." This approach allows us to view augmented human labor as an inclusive opportunity, not a threat. The discipline of Additive Construction is growing rapidly due to the flexibility, speed, safety and logistics benefits offered as compared to standard construction techniques. Additive construction is a disruptive technology in that it employs the principles of additive manufacturing on a human habitat structure scale. Developed initially for emergency management and disaster relief applications, additive construction has now grown into military infrastructure and planetary (Moon and Mars) surface infrastructure applications as well. Additive Construction with Mobile Emplacement (ACME) is a NASA technology development project that seeks to demonstrate the feasibility of constructing shelters for human crews, and other surface infrastructure, on the Moon or Mars for a future human presence. The ACME project will allow, for the first time, the 3-dimensional printing of surface structures on planetary bodies using local materials for construction, thereby tremendously reducing launch and transportation mass and logistics. Some examples of infrastructure that could be constructed using robotic additive construction methods are landing pads, rocket engine blast protection berms, roads, dust free zones, equipment shelters, habitats and radiation shelters. Terrestrial applications include the development of surface structures using Earth-based materials for emergency response, disaster relief, general construction, and housing at all economic levels. This paper will describe the progress made by the NASA ACME project with a focus on prototypes and full scale additive construction demonstrations using both Portland cement concrete and other indigenous material mixtures. Rationale for the use of additive construction for both terrestrial and planetary applications will be explored and a thorough state-of-the-art of additive construction techniques will be presented. An evolutionary history of NASA's additive construction development efforts, dating back to 2004, will be included. The paper will then step through a series of trade studies performed to inform key processing and design decisions in the development of the full-scale ACES-3 system developed by NASA and the Jacobs Space Exploration Group for the U.S. Army Corps of Engineers (USACE) Construction Engineers Research Laboratory (CERL) in Champaign, IL. The selection of aggregate and binders, based on in-situ materials, will also be presented and discussed

Space Processing↗

NASA NTRS2018

UTM UAS Serivce Supplier Development: Sprint 1 Toward Technical Capability Level 4

NASA's UAS Traffic Management (UTM) Project has been tasked with developing concepts and initial implementations for integrating and managing small unmanned aircraft systems (UAS) into the low altitude airspace. To accomplish this task, the Project planned a phased approach based on four Technical Capability Levels (TCLs). As of this writing, TCL4 is currently in development for a late Spring 2019 flight demonstration. This TCL is focused on operations in an urban environment and includes the handling of high density and large-scale off-nominal conditions, vehicle-to-vehicle communications, detect-and-avoid technologies, communication requirements, public safety operations, airspace restrictions, and other related goals. Through research and testing to date, NASA has developed an architecture for UTM that depends on commercial entities collaboratively providing services that are traditionally provided by the Air Navigation Service Provider(ANSP) in manned aviation. A key component of this architecture is the UAS Service Supplier (USS), which acts as a communications bridge between UAS operators and the ANSP when necessary. In addition, the collection of USSs form a USS Network to collaboratively manage the airspace through the sharing of data and the adherence to a standard or set of standards required to participate in this USS Network. This document provides a record of the first step in the development of interoperable USSs that will ultimately support TCL4 flight testing and formalization of the overall UTM concept. To develop these USSs and the underlying specifications for them, NASA has planned a series of "Sprints" to work with industry partners in implementing the features and proposed specifications for USSs to participate in TCL4. This report describes Sprint One. In this Sprint, the focus was on establishing a baseline for the Application Programming Interfaces (APIs) and their associated data models. In addition, the concept of UAS Volume Reservations (UVR) (areas that impose restrictions on sUAS that are allowed to operate) was tested. NASA provided the specifications and iterated on them with partners while implementers developed to those specifications. NASA then tested each partner's implementation to ensure compatibility with all other implementers. This process helped all stakeholders gain confidence that the foundation for future Sprints was solid.

UAS service supplier↗

NASA NTRS2018

Integrated Computational-Experimental Development of Lithium-Air Batteries for Electric Aircraft

The primary obstacle to enable NASA's vision of Green Aviation is the extraordinary energy storage requirements for electric aircraft. Significant advances in high energy, rechargeable, safe batteries are required to enable electric aviation. Boeing's SUGAR and NASA studies have identified 400 Wh/kg as the threshold energy density for general aviation and 750 Wh/kg for commercial regional air service. State of the Art Lithium Ion Battery (LIB) technology currently has a density of 200 Wh/kg and is expected to plateau at 300 Wh/kg due to fundamental chemistry limitations making it unsuitable for future electric aircraft. Additional demanding requirements include high power, rechargeability, and high safety. Such battery technology does not currently exist. The recent considerable activity in battery research (DOE, Tesla Gigafactory, etc) overwhelmingly has been geared towards reducing cost and improving safety of LIB technology in order to promote the adoption of electric automobiles; and thus it is expected to have little impact on electric aviation development. New battery materials will be needed for the "Beyond Li Ion" (BLI) technologies required for high energy, safe electric aviation. Li-Air batteries have the highest known theoretical energy density (3400 Wh/kg) and therefore and if realized promises to transform the global transportation system. These high energy batteries have the potential to meet the energy storage challenges of current and future NASA aeronautics and space missions in addition to many terrestrial transportation applications as well. However, this technology requires significant components development and integration, as it is currently unable to achieve aircraft requirements. The objective of this project is to leverage modern computational materials methods combined with battery multiphysics tools to develop radically advanced compatible cathode and electrolyte materials, build several Li-Air cells, and flight-demonstrate the corresponding Li-Air battery packs. A significant problem for current Lithium-Air batteries is large scale decomposition of the battery electrolyte during operation leading to battery failure after a handful of charge/discharge cycles. Therefore, development of large scale, ultra-high energy, rechargeable, and safe Lithium-Air batteries require highly stable electrolytes that are resistant to decomposition under operating conditions. A NASA-based cross-organizational "dream team" of high-powered experts combined integrated supercomputer modeling, fundamental chemistry analysis, advanced material science, and battery cell development to tackle this very challenging, multidisciplinary problem. The ultimate goal for the team is to develop an integrated experimental/computational infrastructure to produce a reliable predictive capability for the selection of optimal components, their fabrication parameters, and "design rules" of novel cell components for advanced ultra-high energy batteries that can meet energy storage challenges of NASA missions and many terrestrial transportation applications.

Li-air battery↗

NASA NTRS2019

Rapid Development of the Seeker Free-Flying Inspector Guidance, Navigation, and Control System

Seeker is an automated extravehicular free-flying inspector CubeSat designed and built in-house at the Johnson Space Center (JSC). As a Class 1E project funded by the International Space Station (ISS) Program, Seeker had a streamlined process to flight certification, but the vehicle had to be designed, developed, tested, and delivered within approximately one year after authority to pro-ceed (ATP) and within a $1.8 million budget. These constraints necessitated an expedited Guidance, Navigation, and Control (GNC) development schedule, development began with a navigation sensor trade study using Linear Covariance (LinCov) analysis and a rapid sensor downselection process, resulting in the use of commercial off-the-shelf (COTS) sensors which could be procured quickly and subjected to in-house environmental testing to qualify them for flight. A neural network was used to enable a COTS camera to provide bearing measurements for visual navigation. The GNC flight software (FSW) algorithms utilized lean development practices and leveraged the Core Flight Software (CFS) architecture to rapidly develop the GNC system, tune the system parameters, and verify performance in simulation. This pace was anchored by several Hardware-Software Integration (HSI) milestones, which forced the Seeker GNC team to develop the interfaces both between hardware and software and between the GNC domains early in the project and to enable a timely delivery.

Sullivan, Jacob↗

NASA NTRS2019

Rapid Development of the Seeker Free-Flying Inspector Guidance, Navigation, and Control System

Seeker is an automated extravehicular free-flying inspector CubeSat designed and built in-house at the Johnson Space Center (JSC). As a Class 1E project funded by the International Space Station (ISS) Program, Seeker had a stream-lined process to flight certification, but the vehicle had to be designed, developed, tested, and delivered within approximately one year after authority to proceed (ATP) and within a $1.8 million budget. These constraints necessitated an expedited Guidance, Navigation, and Control (GNC) development schedule. Development began with a navigation sensor trade study using Linear Covariance (LinCov) analysis and a rapid sensor down-selection process, resulting in the use of commercial off-the-shelf (COTS) sensors which could be procured quickly and subjected to in-house environmental testing to qualify them for flight. A neural network was used to enable a COTS camera to provide bearing measure-ments for visual navigation. The GNC flight software (FSW) algorithms utilized lean development practices and leveraged the Core Flight Software (CFS) architecture to rapidly develop the GNC system, tune the system parameters, and verify performance in simulation. This pace was anchored by several Hardware-Software Integration (HSI) milestones, which forced the Seeker GNC team to develop the interfaces both between hardware and software and between the GNC domains early in the project and to enable a timely delivery.

Sullivan, Jake↗

NASA NTRS2019

13kW Advanced Electric Propulsion Flight System Development and Qualification

The next phase of robotic and human deep space exploration missions requires high performance, high power solar electric propulsion systems for large-scale science missions and cargo transportation. Aerojet Rocketdyne's Advanced Electric Propulsion System (AEPS) program is completing development and qualification of a 13kW flight EP system to support NASA exploration. The first use of the AEPS is planned for the NASA Power & Propulsion Element, which is the first element of NASA's cis-lunar Gateway. The flight AEPS system includes a magnetically shielded long-life Hall thruster, power processing unit (PPU), and xenon flow controller (XFC). The Hall thruster, originally developed and demonstrated by NASA's Glenn Research Center and the Jet Propulsion Laboratory, operates at input powers up to 13.3kW while providing a specific impulse over 2600s at an input voltage of 600V. The power processor is designed to accommodate an input voltage range of 95 to 140V, consistent with operation beyond the orbit of Mars. The integrated system is continuously throttleable between 3 and 13.3kW. The program has completed testing of the Technology Development Units and is progressing into the Engineering Development Unit test phase and the final design phase to Critical Design Review (CDR). This paper will present the high power AEPS system capabilities, overall program and design status and the latest test results for the 13kW flight system development as well as the plans for the development and qualification effort of the EP string.

in-space propulsion↗

NASA NTRS2019

13kW Advanced Electric Propulsion Flight System Development and Qualification

in-space propulsion↗

NASA NTRS2020

Medical Data Architecture Prototype Development - Summary of Recent Work and Proposed Ideas for Upcoming Work

The Medical Data Architecture (MDA) project supports the Exploration Medical Capability (ExMC) risk to minimize or reduce the risk of adverse health outcomes and decrements in performance due to in-flight medical capabilities on human exploration missions. To mitigate this risk, the ExMC MDA project addresses the technical limitations identified in ExMC Gap Med 07: We do not have the capability to comprehensively process medically-relevant information to support medical operations during exploration missions, and in ExMC Gap Med 10: We do not have the capability to provide computed medical decision support during exploration missions. These gaps recognize the need for a comprehensive medical data management system and the accompanying computational support to provide autonomous medical care during long duration exploration missions. As the MDA matures—including the capability to comprehensively process and discover medically-relevant information to support medical operations during exploration missions—project focus will shift to maturing and extending the MDA platform to enable clinical decision support and real-time guidance. To date, the MDA foundational architecture has recommended exploration medical system Level of Care IV requirements through a series of test bed prototype developments and analog demonstrations. The next stage in the development will focus on more autonomous clinical decision making necessary to address challenges in executing a self-contained medical system that enables health care both with and without assistance from ground support. A thorough understanding of current state of medical decision support systems, advanced machine learning algorithms and vast and varied data sources is required. The development of a clinical decision support for exploration missions (Level of Care V) roadmap is needed: one that assesses of current state of the art of clinical decision support systems (CDSS), interoperability issues, identification of challenges in health and performance monitoring, obtaining and processing information from biosensors, knowledge and data management, data integration and fusion, and advanced algorithm development. This roadmap must also include rapid prototype development in the areas of data processing, advanced analysis and prediction of medical events, and treatment based on medically relevant information processing and evidence-based best practices. In this presentation, an overview of the relevant issues and the beginning framework of a Level of Care V CDSS development roadmap will be provided.

Krihak, M.↗

NASA NTRS2019

Assessment of Buffet Forcing Function Development Process Using Unsteady Pressure Sensitive Paint

A wind tunnel test was conducted at the Ames Unitary Plan Wind Tunnel to characterize the transonic buffet environment of a generic launch vehicle forebody. The test examined a highly instrumented version of the Coe and Nute Model 11 test article first tested in the 1960s. One of the measurement techniques used during this test was unsteady pressure sensitive paint (uPSP) developed at the Arnold Engineering Development Complex. This optical measurement technique measured fluctuating pressures at over 300,000 locations on the surface of the model. The high spatial density of these measurements provided an opportunity to examine in depth the assumptions underpinning the development of buffet forcing functions (BFFs) used in the development of the Space Launch System vehicle. The comparison of discrete-measurement-based BFFs to BFFs developed by continuous surface pressure integration indicates that the current BFF development approach under predicts low frequency content of the BFFs while over predicting high frequency content. Coherence-based adjustments employed to reduce over prediction in the surface integration of discrete pressure measurements contribute to the inaccuracy of the BFFs and their implementation should be reevaluated.

Sekula, Martin K.↗

NASA NTRS2018

T-infinity: The Dependency Inversion Principle for Rapid and Sustainable Multidisciplinary Software Development

The CFD Vision 2030 Study recommends that, “NASA should develop and maintain an integrated simulation and software development infrastructure to enable rapid CFD technology maturation.... [S]oftware standards and interfaces must be emphasized and supported whenever possible, and open source models for noncritical technology components should be adopted.” The current paper presents an approach to an open source development architecture, named T-infinity, for accelerated research in CFD leveraging the Dependency Inversion Principle to realize plugins that communicate through collections of functions without exposing internal data structures. Steady state flow visualization, mesh adaptation, fluid-structure interaction, and overset domain capabilities are demonstrated through compositions of plugins via standardized abstract interfaces without the need for source code dependencies between disciplines. Plugins interact through abstract interfaces thereby avoiding N 2 direct code-to-code data structure coupling where N is the number of codes. This plugin architecture enhances sustainable development by controlling the interaction between components to limit software complexity growth. The use of T-infinity abstract interfaces enables multidisciplinary application developers to leverage legacy applications alongside newly-developed capabilities. While rein, a description of interface details is deferred until the are more thoroughly tested and can be closed to modification.

O'Connell, Matthew D.↗