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NASA NTRS2018

Resolution of a Reflector Shroud Fatigue Failure

Two cracks were observed on a reflector shroud for a space program after previously being subjected to the protoflight test campaign and several regression tests. After extensive analysis and investigations, the failure mechanism was identified to be fatigue as a result of the numerous vibration tests imposed on the unit. Two feasible corrective actions were proposed: first, a notched vibration profile which possesses sufficient margin from the anticipated acoustic and launch loads, while maintaining adequate fatigue life through launch and on-orbit operations, and second, a re-design of the shroud to strengthen the fatigue-susceptible areas. In this paper, we present the inspections, testing, and analysis performed to establish that the cracks were a result of fatigue failure. We discuss the conservative fatigue analysis methodology used in the development of both corrective action options. Finally, we review the lessons learned and the actions incorporated into the rework, subsequent regression testing, and the test plans to minimize the risk of recurrence in future units.

response limiting↗

NASA NTRS2014

ADEPT for Secondary Payloads

Deployable entry vehicles provide an enabling capability for large payloads at destinations across the solar system. The primary advantage of such systems derives from the fundamental limitation of available launch vehicle shroads preventing tried-and-true rigid aeroshell technology from being applied. However, little mission-pull exists for deployable entry vehicle technology for missions where the entry vehicle is the primary payload and can fit within available shrouds. The propensity toward applying rigid aeroshell technology is logical given that deployable concepts are higher risk and provide no marginal scientific benefit for missions where a rigid aeroshell is an option. A movement toward flying smaller spacecraft has emerged in recent years and is revealing novel applications for deployable entry vehicles as secondary payloads. Secondary payloads must minimize interference with the primary payload in order to ease accomodation. Advancements in small spacecraft technology have caught the attention of government entities who are now recognizing the high value proposition of small spacecraft for frequent, incremental technology development and science return rather than the traditional high cost and infrequent big-bang approaches. Worldwide, well over 200 small satellites (mass < 180 kg) have launched in recent years for such purposes as eduation, technology development, science, commerce, and defense. The Adaptable Deployable Entry and Placement Technology (ADEPT), a mechanically-deployable entry vehicle technology, has been under development at NASA since 2011. An Ames Center Innovation Fund (CIF) proposal was recently awarded to study ADEPT for EDL of small payloads. The unique capability of ADEPT for small science payloads comes from its ability to stow within a slender volume and deploy passively to achieve a mass-efficient drag surface with a high heat rate capability. The low ballistic coefficient results in entry heating and mechanical loads that can be met by a revolutionary three-dimensionally woven carbon fabric supported with rib structures. This carbon fabric has test-proven capability as both primary structure and payload thermal protection. This presentation will inform the EDL community of the capability of ADEPT for delivery of small secondary payloads as well as provide status of on-going technology development activities. Results of a mission applications study for secondary payloads to Mars and Venus will be presented. A primary goal of these mission design activities is to integrate high-value verification approaches wherever possible. For example, for some mission applications it is possible to test in NASA arc jet facilities at full-scale. This enables endto- end thermostructural requirement verification with a single test. Another important challenge that needs to be solved is the reliability of the decelerator to achieve the desired shape using simple passive mechanical actuators (such as springs) that do not require power from the primary payload for deployment. A configuration of ADEPT is being prototyped and used to evaluate the functionality and reliability of the deployment mechanism through bench-top testing. The prototype will then be tested in a low speed wind tunnel in late 2014 to evaluate aerodynamic load-carrying capability and deflected shape. Results of the deployment testing and status of wind tunnel test plans will be discussed.

Smith, B.↗

NASA NTRS2016

A Structured, Model-Based Systems Engineering Methodology for Operations System Design

Two widely accepted techniques for lowering the cost and risk of developing systems are (1) the use of a defined systems engineering (SE) process or methodology and (2) the reuse of existing (previously built) system components. The first technique is represented, for example, in materials published by NASA (e.g., NASA Systems Engineering Handbook) or by professional societies such as INCOSE (International Council on Systems Engineering). Well-formed SE techniques provide value by establishing the proper scope of the system (e.g., requirements), and by identifying and resolving problems relatively early in project lifecycles, when fixes are less expensive. The second technique (reuse) is applied most commonly to hardware and software; it seeks to avoid replicating design and implementation costs while also reducing risk by placing proven capabilities into operational use. In this paper, we outline a methodology combining these two techniques and extending reuse beyond hardware and software to foundational aspects of a Mission Operation System’s (MOS) design. We describe the system design artifacts that result (e.g., requirements, design documentation), as well as the reusable patterns and elements of the design, and their interrelationships. This approach is enabled by model-based systems engineering (MBSE) techniques and tools and is currently available in SysML form as a plug-in to MagicDraw. Additionally, usage of a rigorous MBSE approach allows for training materials and tutorials to be packaged within the overall model itself. The results of such an approach include decreased cost and risk during the design phase, improved ability of the MOS development team to investigate trade spaces and identify impacts to important flight-ground trade studies. Such results extend into decreased costs and risk in later phases due to improved design, decreased need for late fixes or development of "glue-ware" or scripts to fill unanticipated gaps in functionality, and improved ability to identify and plan testing and other validation activities. Finally, lower operational costs can be expected, both due to improved quality of the MOS, increased ease of maintaining updated knowledge of system configuration, and the fact that training and procedural materials are also updated at the same time as accepted system changes.

Bindschadler, Duane L.↗

NASA NTRS2018

Preparation of Papers for AIAA Technical Conferences

As the extent of human spaceflight becomes longer in duration and farther from Earth, there will be a need for astronauts to grow plants during their mission in order to have a source of food production. In order to have confidence in the effectiveness of this off-Earth food production system, it will need to be proven reliable before any long duration missions take place. For this reason, the Utilization & Life Sciences Office at NASA Kennedy Space Center (KSC) is developing a test platform for components testing of a plant growing system.In order to ensure that this test platform is an effective stepping stone for a future plant growing system, this fall, internship contributions will include developing requirements and an integrated testing plan. This may include level 1, level 2, and level 3 requirements depending on the necessity of requirement detail.

Greaves, Benjamin J.↗

NASA NTRS2019

Overview of JPSS VIIRS Geometric Calibration and Validation

The presentation stressed the importance of a pre-launch test plan and a post-launch CalVal plan in the geometric aspects of instrument focal length, spatial responses, band-to-band registration, pointing, geolocation and long-term monitoring.

VIIRS↗

NASA NTRS2019

Ultrasonic Gear Steel Fatigue at NASA

Gear tooth bending fatigue life is one of the main drivers of rotorcraft gear box weight and maintenance cost. Depending on rotorcraft gearbox speed, 10,000 flight hours can easily mean reaching gear tooth bending fatigue cycles in the 10^10 cycle regime. Traditionally gear fatigue life in the 10^10 cycle regime is estimated based on empirical correction factors applied to the traditional fatigue limit of 10^7 cycles. In order to improve on this method of life prediction, enable better gear box design, and reduce gear box maintenance cost, NASA has started an ultrasonic gear steel fatigue program to quantify the 10^10 life of gear steels. Ultrasonic fatigue testing makes use of piezo electric actuators and resonance to generate stress-strain cycles at 20 kHz. The ability to test gear steals at 20 kHz reduces test time for 10^10 cycles from roughly 16 years with traditional 20 Hz testing to 6 days. In this presentation, the establishment of NASA's ultrasonic test capability, results to date, and future testing plans will be discussed.

Tallerico, Thomas F.↗

NASA NTRS2019

Landsat 9: Mission Status and Prelaunch Instrument Performance Characterization and Calibration

Landsat 9 is currently under development as a joint effort between NASA and the United States Geological Survey (USGS). Landsat 9 is essentially a rebuild of Landsat 8 and has the same two sensors, the Operational Land Imager (OLI) and the Thermal Imaging Sensor (TIRS). The OLI-2 on Landsat 9, is being built by Ball Aerospace and has completed its pre-launch characterization and calibration and is scheduled to be delivered in the summer of 2019. The TIRS-2, being built by Goddard Space Flight Center, is currently undergoing testing through Spring 2019 and also scheduled for summer 2019 delivery. Several improvements to the characterization of both instruments have been incorporated into the testing plan, including improved spectral and radiometric characterization. The instruments will then be integrated onto the spacecraft being built by Northrop Grumman Innovation Systems (NGIS). The mission is targeted to launch as early as December 2020 on an Atlas-5.

Markham, Brian↗

NASA NTRS2019

Landsat 9: Mission Status and Prelaunch Instrument Performance Characterization and Calibration

Markham, Brian↗

NASA NTRSDate not supplied

Estimating the Noise Floor of Sonic Boom Metrics Across the USA

NASA is building the X-59 Quiet Supersonic Technology aircraft to produce low noise sonic booms for a series of community noise surveys across the USA. Survey participants will rate their perception of the low booms from supersonic X-59 flyovers. Several noise metrics are proposed to quantify the noise dose: A-, B-, D-, E-weighted Sound Exposure Level, Stevens Perceived Level, and Indoor Sonic Boom Annoyance Predictor. Sparse measurements across the survey area will be used to estimate community noise exposure. The level of these low booms may be comparable to the ambient noise level in some locations, leading to uncertainty in noise exposure estimations. This uncertainty may necessitate increased reliance on sonic boom propagation predictions for exposure estimation. Low-boom signal to ambient noise ratio is one way to quantify uncertainty in measured sonic boom levels. An empirical relationship between A-weighted ambient level and sonic boom metric levels is used in conjunction with the National Park Service’s L50 SPL map to estimate sonic boom metric ambient levels across the USA. The estimate of ambient sonic boom metric levels will aid in X-59 test planning and execution.

sonic boom↗

NASA NTRSDate not supplied

UTM to AAM

This short presentation is intended to provide a a brief overview of the background of the UAS Traffic Management (UTM) concept and the legacy of work performed in the area of human factors as part of the project's research. The introduction of UTM provides the foundation for presenting the progression of the concept from low altitude airspace with small UAS to an environment with larger passenger and cargo carrying vehicles integrating into more complex airspace as part of the Advanced Air Mobility (AAM) concept. Related research and testing plans are presented to illustrate the direction of related project efforts as well as the facilities that are available to support the necessary research ahead.

UTM↗

NASA NTRS2019

LANDSAT 9: Mission Status and Prelaunch Instrument Performance Characterization and Calibration

Landsat 9 is currently under development as a joint effort between NASA and the United States Geological Survey (USGS). Landsat 9 is largely a rebuild of Landsat 8 and has the same two sensors, an Operational Land Imager (OLI) and a Thermal InfraRed Sensor(TIRS). The OLI-2 on Landsat 9, being built by Ball Aerospace, has completed its pre-launch characterization and calibration and is scheduled to be delivered in the summer of 2019. The TIRS-2, with improved stray light performance and increased redundancy for improved reliability, is being built by Goddard Space Flight Center. TIRS-2is undergoing testing through Spring 2019 and is also scheduled for summer2019 delivery. Several improvements to the characterization of both instruments have been incorporated into the testing plan, including improved spectral and radiometric characterization. The instruments will then be integrated onto the spacecraft being built by Northrop Grumman Innovation Systems (NGIS). The mission is targeted to launch as early as December 2020 on an Atlas V.

Landsat↗

NASA NTRS2003

Bringing an effective solar sail design toward TRL 6

This document outlines the accomplishments of a Phase 1 effort to advance the technology readiness level of the concept from 3 toward a TRL of 6. The Phase 1 effort, the first of three proposed phases, addressed the design of the solar sail, its application to several missions currently under review at NASA, and developed a ground test plan to bring the technology toward a TRL of 6.

Pappa, Richard↗

NASA NTRS1995

The MISR Calibration Program

The Multi-angle Imaging SpectroRadiometer (MISR) is currently under development for NASA's Earth Observing System (EOS). The instrument consists of nine pushbroom cameras, each with four spectral bands in the visible and near-infrared. Detailed are the MISR preflight characteristics, design of the On-Board Calibrator, and the radiance product processing. Detailed specifications and test plans are given.

multi-angle↗

NASA NTRS2019

The SPLICE Project: Continuing NASA Development of GN&C Technologies for Safe and Precise Landing

Guidance, Navigation and Control (GN&C) technologies for precise and safe landing are essential for future robotic science and human exploration missions to solar system destinations with targeted surface locations that pose a signiﬁcant risk to successful landing and subsequent mission operations. These Entry, Descent and Landing (EDL) technologies are a part of the NASA domain called PL&HA (Precision Landing and Hazard Avoidance) and are considered high-priority capabilities within NASA space technology development roadmaps to promote and enable new mission concepts. The SPLICE (Safe & Precise Landing – Integrated Capabilities Evolution) project is a multi-center, multi-directorate NASA project focused on continuing the decade-plus of NASA investments and projects focused on PL&HA technology development and infusion. This paper highlights the GN&C technologies in development within SPLICE, along with the simulation and ﬁeld test plans for validation of the capabilities and Technology Readiness Level (TRL) maturation toward infusion into potential near-term robotic lunar landing missions.

Tse, Teming↗

NASA NTRS2018

A 6U Hybrid Propulsion Module for CUBESATS

A 6U hybrid propulsion module is presented. It is designed to be used as a stage for a 6U CubeSat with a combined wet mass up to 25 kg. Hybrid rocket propulsion is utilized because it is responsive, high performance, capable of multiple burns and safe/non-toxic. Hybrid rockets employ a solid fuel and liquid or gaseous oxidizer. In this case, the fuel is PolyMethyl MethAcrylate and the oxidizer is gaseous oxygen. This propellant combination produces an Isp of greater than 300 seconds. The gaseous oxidizer simplifies the design and is used in dual mode with cold gas thrusters for attitude control. In general, hybrid propulsion is higher performance and higher thrust than conventional options considered for CubeSats (e.g. monopropellants), making it ideal for larger manuevers such as plane changes. The Attitude Control System has been sized to ensure that the CubeSat can be controlled under the thrust loads of the propulsion system. A hybrid rocket motor of this size is currently being tested at the Jet Propulsion Laboratory. Thirty-four successful tests have been completed at JPL with this propellant combination during the last 2.5 years. Current tests include long duration tests (> 95 seconds) and multiple starts (five). These tests and applicability to potential mission requirements will be discussed. Future test plans to move the motor into a vacuum facility to achieve a Technology Readiness Level of 5 by the end of September 2018 will be discussed, and an overview of the proposed TRL 5 to 6 maturity plan will also be presented.

Nakazono, B.↗

NASA NTRS2020

Advanced High-Lift Leading-Edge (AHLLE) Technologies for Laminar Wings

This is the Northrop Grumman final report for the Advanced High-Lift Leading-Edge Technologies for Laminar Wings conceptual design and demonstration program performed for the National Aeronautics and Space Administration Langley Research Center. Northrop Grumman conducted conceptual aerodynamic CFD and QFD analysis to downselect two leading-edge concepts for high lift. The effort included aerodynamic analysis to examine instrumentation placement and propulsion analysis to design internal cavity geometry of the high-pressure blown slot configurations. A wind tunnel model design created a 7-foot span model of the complex configuration. A wind tunnel test plan, which included baseline, deflected trailing-edge, blown deflected trailing-edge, blown leading-edge, morphed leading-edge, and blown/morphed leading-edge airfoil configurations was developed. As a result of this program approach, a successful demonstration of high-lift leading-edge technology was reached, and the target goals for improved lift were exceeded by 30% with a maximum section lift coefficient (Cl) of 5.2. Incremental lift coefficient (DCl) of 3.5 and 3.1 was achieved on the two laminar compatible airfoil configurations (at cruise). Our high-lift design yielded a massive 94% lift improvement over conventional high-lift Krueger flap configurations while providing laminar flow capability on the cruise configuration.

High-lift↗

NASA NTRSDate not supplied

Overview of Predictive Simulation Capability Development for Crater Evolution and Ejecta in Continuum/Rarefied Flows

As part of the Game Changing Development (GCD) Program, funded by NASA’s Space Technology Mission Directorate (STMD), the development of simulation capability for the prediction of extra-terrestrial Plume Surface Interaction (PSI) environments has been undertaken by the Fluid Dynamics Branch at NASA/MSFC. The Predictive Simulation Capability (PSC) Element is focused on creating simulation capability for the reliable and accurate prediction of PSI in Martian (~650 Pa) and Lunar (vacuum) ambient environments. In addition to the predictive simulation capability, the GCD Program also contains a companion Ground Testing Element for development of focused datasets for validation of predictive capability as well as a Flight-focused Instrumentation Element. The focus of this paper is to provide an overview and a brief status on one area of capability development through this GCD PSI project - capturing the effects of mixed continuum/rarefied flow on crater development and ejecta sheets. This includes both capability enhancements and maturation of the predictive tool, Loci/GGFS, into a production capable tool as well as validation of the tool against PSI data in Martian and Lunar environments. There are six newly developed capabilities that will be production ready by the end of the fiscal year. Newly developed capabilities must first be verified prior to being production ready, and this process includes capability demonstration, solution verification, and performance evaluation. An overview of the newly developed capabilities with respect to several test cases, including cratering simulations of the Apollo Lunar Module, will be presented. Several validation analyses have been performed to validate in Martian and more Lunar-like environments, including simulations of cratering from a subsonic flow test at Planetary Aeolian Lab (PAL) conducted in a Martian-like environment and pre-test cratering predictions of Physics Focused Ground Test (PFGT) tests planned to be performed in Martian-like and more Lunar-like environments. An overview of these validation analyses as it pertains to the capability development will be presented.

Andrew Weaver↗

NASA NTRSDate not supplied

Rapid Assessment of a Lunar Surface Laboratory Module

Johnson Space Center is piloting an innovation team known as the Forge to perform rapid turnaround, concurrent engineering studies. The Forge is intended to be able to pull together a team of strategically selected domain experts to innovatively solve a specified problem within a short period of time. The Forge’s inaugural project being the development of a Lunar Surface Laboratory Module concept. The lab module is intended as an option for the Artemis program’s Lunar Architecture Team. The lab module may allow for increased science productivity and return on investment than a surface architecture with only the habitat. This paper will discuss the configuration of the Lunar Laboratory module, including the pressure vessel, its placement relative to the Surface Habitat and Pressurized Rover, and internal architecture. In order to determine the suitability of such a design, a human factors evaluation is conducted. Historically, a human factors evaluation of a habitable volume could require a month or longer, including time needed to prepare a test plan, conduct the evaluation, compile the data, and produce a report. The entire Forge effort will only last for five weeks, forcing the creation of a rapid assessment process. This rapid assessment includes three evaluation studies, all conducted and processed in the space of a single day, to determine the acceptability of the resulting design. The first evaluation is a card sort evaluation of the laboratory instruments. A brief discussion of the card sort evaluation is provided. This card sort is focused on the relative positioning of the laboratory instruments, determining whether a given instrument should be adjacent to, or separated from, another. It will use human factors personnel and both life and physical scientists as subject matter experts. The second evaluation is a science productivity tabletop evaluation. This evaluation focuses on the selection of instruments and the number of instruments, attempting to assess the amount of work the crew will be able to use the facility to do. It uses life and physical science personnel as subject matter experts. The third evaluation is a CAD or Virtual Reality human factors walkthrough evaluation. This evaluation focuses on the layout of the lab module and its connectivity to the basecamp’s pressurized elements. If possible, astronauts will be used as subject matter experts. Each of these evaluations will focus primarily on objective data with limited subjective comments, reducing the time required for processing responses. The results of each evaluation and their implications will be discussed. Based on the evaluation data, an overall acceptability of the Lunar Surface Laboratory Module produced by the Forge study can be determined. Lessons learned and recommendations for future use of the human factors rapid assessment process in early design trades will also be provided.

Lunar Laboratory↗