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At least 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS2015

The Europa Mission: Multiple Europa Flyby Trajectory Design Trades and Challenges

With potential sources of water, energy and other chemicals essential for life, Europa is a top candidate for finding current life in our Solar System outside of Earth. This paper describes the current trajectory design concept for a multiple Europa flyby mission and discusses several trajectory design challenges. The candidate reference trajectory utilizes multiple Europa flybys while around Jupiter to enable near global coverage of Europa while balancing science requirements, radiation dose, propellant usage, and flight time. Trajectory design trades and robustness are also discussed.

Jupiter↗
NASA NTRS2016

Engineering Design Tools for Shape Memory Alloy Actuators: CASMART Collaborative Best Practices and Case Studies

The primary goal of the Consortium for the Advancement of Shape Memory Alloy Research and Technology (CASMART) is to enable the design of revolutionary applications based on shape memory alloy (SMA) technology. In order to help realize this goal and reduce the development time and required experience for the fabrication of SMA actuation systems, several modeling tools have been developed for common actuator types and are discussed herein along with case studies, which highlight the capabilities and limitations of these tools. Due to their ability to sustain high stresses and recover large deformations, SMAs have many potential applications as reliable, lightweight, solid-state actuators. Their advantage over classical actuators can also be further improved when the actuator geometry is modified to fit the specific application. In this paper, three common actuator designs are studied: wires, which are lightweight, low-profile, and easily implemented; springs, which offer actuation strokes upwards of 200 at reduced mechanical loads; and torque tubes, which can provide large actuation forces in small volumes and develop a repeatable zero-load actuation response (known as the two-way shape memory effect). The modeling frameworks, which have been implemented in the design tools, are developed for each of these frequently used SMA actuator types. In order to demonstrate the versatility and flexibility of the presented design tools, as well as validate their modeling framework, several design challenges were completed. These case studies include the design and development of an active hinge for the deployment of a solar array or foldable space structure, an adaptive solar array deployment and positioning system, a passive air temperature controller for regulation flow temperatures inside of a jet engine, and a redesign of the Corvette active hatch, which allows for pressure equalization of the car interior. For each of the presented case studies, a prototype or proof-of-concept was fabricated and the experimental results and lessons learned are discussed. This analysis presents a collection of CASMART collaborative best practices in order to allow readers to utilize the available design tools and understand their modeling principles. These design tools, which are based on engineering models, can provide first-order optimal designs and are a basic and efficient method for either demonstrating design feasibility or refining design parameters. Although the design and integration of an SMA-based actuation system always requires application- and environment-specific engineering considerations, common modeling tools can significantly reduce the investment required for actuation system development and provide valuable engineering insight.

Design tools↗
NASA NTRS2018

Mission Design and Implementation Considerations for Lunar Night Survival

Lunar night survival, while being a technical design challenge, also has an impact on mis-sion planning and execution during the flight system development phases (Phases A-D). Depending on mis-sion objectives, different locations on the lunar surface result in different challenges to technical formulation of a comprehensive mission design and implementa-tion. Equatorial regions have temperature extremes between day and night (<100K to >380K) but are somewhat cyclical and predictable. Polar regions can have milder thermal environments in terms of overall surface temperature swing and opportunities for ex-tended durations for solar power but pose unique chal-lenges in temporal and spatial availability of both sun-light and direct-to-Earth communications. Options for surviving the night will depend heavily on mission objectives, lunar location and program cost and schedule constraints.

Vaughan, R.↗
NASA NTRSDate not supplied

2024 Nasa Lunabotics University Competition: Site Preparation With Bulk Regolith

Introduction: Lunabotics provides accredited institutions of higher learning students (vocational-technical, college, university) an opportunity to apply the NASA systems engineering process to design and build a prototype robot. This robot would be capable of performing the proposed operations on the Lunar surface in support of future Artemis mission goals. Lunabotics features a systems engineering design challenge to engage students in the next phase of hu-man space exploration supporting the Artemis missions. This two-semester event encourages students to design and build an autonomous or telerobotic robot designed to traverse the simulated Lunar surface and complete the assigned construction tasks. The number of teams accepted into this challenge is not predetermined but is based on the scores and overall quality of the Project Management Plans received and other factors. The culmination of the Lunabotics virtual challenge will be the design, build and operation of a functional prototype Lunar robot. Teams are required to submit the following: (1) Project Management Plan, (2) Systems Engineering Paper, a (3) STEM Engage-ment Report, and a (4) Proof of Life Video. This is an optional item, but to qualify for the grand prize a team must also submit a: (5) Presentation and Demonstration. Background: The NASA Lunabotics University Competition was first held in 2010 as a follow on to the NASA Regolith Excavation Challenge [1]. The high level of interest and participation from over 50 universities each year has led to a sustained annual competi-ion cadence: it has been held every May for the past 14 years [2,3]. Over 6,000 students have participated and been inspired to pursue Science, Technology, En-gineering and Mathematics careers (STEM). 2024 Competition: The necessary lunar surface tasks are evolving to meet the NASA Artemis Mission requirements. In the past Lunabotics challenges we gathered data to support Lunar mining for consuma-bles in the Lunar regolith. Now, in 2024, the task is to gather data on Lunar site preparation and construction by designing and building a robot that will traverse the chaotic Lunar terrain and construct a regolith-based berm. The goal is to build a berm structure which would be useful to the Artemis Mission for blast and ejecta protection during lunar landings and launches, shading cryogenic propellant tank farms, providing radiation protection around a nuclear power plant and other mission critical uses. Lunabotics will consist of three separate events this year. The first event is NASA’s Lunabotics Project Development Challenge, where teams submit various deliverables to be scored by judges. The second event will be the University of Central Florida (UCF) Lunabotics Qualification challenge, in the Exolith laboratory, where teams will put their de-signs to the test. The top ten scoring teams from the Qualification challenge are then invited to the third and final event, NASA’s Lunabotics On-Site Challenge at Kennedy Space Center in Florida. This presentation will summarize the results and lessons learned from the NASA Lunabotics University Competition held in May 2024.

Lunabotics↗
NASA NTRS2012

JWST's Cryogenic Position Metrology System

The James Webb Space Telescope will undergo a full system test in the cryogenic vacuum chamber A at the Johnson Spaceflight Center in order to verify the overall performance of the combined telescope and instrument suite. This will be the largest and most extensive cryogenic test ever undertaken. Early in the test system development, it was determined that precise position measurements of the overall hardware would enhance the test results. Various concepts were considered before selecting photogrammetry for this metrology. Photogrammetry has been used in space systems for decades, however cryogenic use combined with the size and the optical/thermal sensitivity of JWST creates a unique set of implementation challenges. This paper provides an overview of the JWST photogrammetric system and mitigation strategies for three key engineering design challenges: 1) the thermal design of the viewing windows to prevent excessive heat leak and stray light to the test article 2) cost effective motors and mechanisms to provide the angle diversity required, and 3) camera-flash life and reliability sufficient for inaccessible use during the number and duration of the cryogenic tests.

Whitman, Tony L.↗
NASA NTRS2002

The Personal Satellite Assistant: An Internal Spacecraft Autonomous Mobile Monitor

This paper presents an overview of the research and development effort at the NASA Ames Research Center to create an internal spacecraft autonomous mobile monitor capable of performing intra-vehicular sensing activities by autonomously navigating onboard the International Space Station. We describe the capabilities, mission roles, rationale, high-level functional requirements, and design challenges for an autonomous mobile monitor. The rapid prototyping design methodology used, in which five prototypes of increasing fidelity are designed, is described as well as the status of these prototypes, of which two are operational and being tested, and one is actively being designed. The physical test facilities used to perform ground testing are briefly described, including a micro-gravity test facility that permits a prototype to propel itself in 3 dimensions with 6 degrees-of-freedom as if it were in an micro-gravity environment. We also describe an overview of the autonomy framework and its components including the software simulators used in the development process. Sample mission test scenarios are also described. The paper concludes with a discussion of future and related work followed by the summary.

Dorais, Gregory A.↗
NASA NTRS2011

Design and Analysis of Mirror Modules for IXO and Beyond

Advancements in X-ray astronomy demand thin, light, and closely packed thin optics which lend themselves to segmentation of the annular mirrors and, in turn, a modular approach to the mirror design. The functionality requirements of such a mirror module are well understood. A baseline modular concept for the proposed International X-Ray Observatory (IXO) Flight Mirror Assembly (FMA) consisting of 14,000 glass mirror segments divided into 60 modules was developed and extensively analyzed. Through this development, our understanding of module loads, mirror stress, thermal performance, and gravity distortion have greatly progressed. The latest progress in each of these areas is discussed herein. Gravity distortion during horizontal X-ray testing and on-orbit thermal performance have proved especially difficult design challenges. In light of these challenges, fundamental trades in modular X-ray mirror design have been performed. Future directions in module X-ray mirror design are explored including the development of a 1.8 m diameter FMA utilizing smaller mirror modules. The effect of module size on mirror stress, module self-weight distortion, thermal control, and range of segment sizes required is explored with advantages demonstrated from smaller module size in most cases.

McClelland, Ryan S.↗
NASA NTRS2015

Development of the PRSEUS Multi-Bay Pressure Box for a Hybrid Wing Body Vehicle

NASA has created the Environmentally Responsible Aviation Project to explore and document the feasibility, benefits, and technical risk of advanced vehicle configurations and enabling technologies that will reduce the impact of aviation on the environment. A critical aspect of this pursuit is the development of a lighter, more robust airframe that will enable the introduction of unconventional aircraft configurations that have higher lift-to-drag ratios, reduced drag, and lower community noise. Although such novel configurations like the Hybrid Wing Body (HWB) offer better aerodynamic performance as compared to traditional tube-and-wing aircraft, their blended wing shapes also pose significant new design challenges. Developing an improved structural concept that is capable of meeting the structural weight fraction allocated for these non-circular pressurized cabins is the primary obstacle in implementing large lifting-body designs. To address this challenge, researchers at NASA and The Boeing Company are working together to advance new structural concepts like the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS), which is an integrally stiffened panel design that is stitched together and designed to maintain residual load-carrying capabilities under a variety of damage scenarios. The large-scale multi-bay fuselage test article described in this paper is the final specimen in a building-block test program that was conceived to demonstrate the feasibility of meeting the structural weight goals established for the HWB pressure cabin.

Jegley, Dawn C.↗
NASA NTRS2011

Development and Deployment of Robonaut 2 to the International Space Station

The development of the Robonaut 2 (R2) system was a joint endeavor with NASA and General Motors, producing robots strong enough to do work, yet safe enough to be trusted to work near humans. To date two R2 units have been produced, designated as R2A and R2B. This follows more than a decade of work on the Robonaut 1 units that produced advances in dexterity, tele-presence, remote supervision across time delay, combining mobility with manipulation, human-robot interaction, force control and autonomous grasping. Design challenges for the R2 included higher speed, smaller packaging, more dexterous fingers, more sensitive perception, soft drivetrain design, and the overall implementation of a system software approach for human safety, At the time of this writing the R2B unit was poised for launch to the International Space Station (ISS) aboard STS-133. R2 will be the first humanoid robot in space, and is arguably the most sophisticated robot in the world, bringing NASA into the 21st century as the world's leader in this field. Joining the other robots already on ISS, the station is now an exciting lab for robot experiments and utilization. A particular challenge for this project has been the design and certification of the robot and its software for work near humans. The 3 layer software systems will be described, and the path to ISS certification will be reviewed. R2 will go through a series of ISS checkout tests during 2011. A taskboard was shipped with the robot that will be used to compare R2B's dexterous manipulation in zero gravity with the ground robot s ability to handle similar objects in Earth s gravity. R2's taskboard has panels with increasingly difficult tasks, starting with switches, progressing to connectors and eventually handling softgoods. The taskboard is modular, and new interfaces and experiments will be built up using equipment already on ISS. Since the objective is to test R2 performing tasks with human interfaces, hardware abounds on ISS and the crew will be involved to help select tasks that are dull, dirty or dangerous. Future plans for R2 include a series of upgrades, evolving from static IVA (Intravehicular Activity) operations, to mobile IVA, then EVA (Extravehicular Activity).

Ambrose, Robert O.↗
NASA NTRS2015

Ultra-Compact Ka-Band Parabolic Deployable Antenna for RADAR and Interplanetary CubeSats

Over the past several years, technology and launch opportunities for CubeSats have exploded, enabling a wide variety of missions. However, as instruments become more complex and CubeSats travel deeper into space, data communication rates become an issue. To solve this challenge, JPL has initiated a research and technology development effort to design a 0.5 meter Ka-band parabolic deployable antenna (KaPDA) which would stow in 1.5U (10 x 10 x 15 cu cm) and provide 42dB of gain (50% efficiency). A folding rib architecture and dual reflector Cassegrainian design was selected as it best balances RF gain and stowed size. The design implements an innovative telescoping waveguide and gas powered deployment. RF simulations show that after losses, the antenna would have over 42 dB gain, supported by preliminary test results. KaPDA would create opportunities for a host of new CubeSat missions by allowing high data rate communication which would enable using high fidelity instruments or venturing further into deep space, including potential interplanetary missions. Additionally KaPDA would provide a solution for other small antenna needs and the opportunity to obtain Earth science data. This paper discusses the design challenges encountered, the architecture of the solution, and the antennas expected performance capabilities.

Sauder, Jonathan↗
NASA NTRSDate not supplied

Modeling Validation and Its Design Relevance for NTP Fuel Elements

The development of Nuclear Thermal Propulsion engines depends heavily on modeling and simulation of a number of disciplines—neutronic / fluid / thermal / structural are only a start. Further, rockets involve extreme conditions, particularly high material temperatures in the nuclear fuel. This paper considers validation of the underling physical models and codes and how their accuracy influences several design challenges. Several issues are identified, where models, material data, could enable design solutions. In particular, thermal and CTE mismatch stresses are a concern, and stress predictions would benefit from improved mechanical property data at high temperatures. Nuclear inter-element heating causes propellant flow maldistribution and performance risks, but a simple model provides insights. High temperature chemical diffusion should be modeled to understand fuel element mass loss.

Nuclear Propulsion↗
NASA NTRSDate not supplied

Modeling Validation and Its Design Relevance for NTP Fuel Elements

The development of Nuclear Thermal Propulsion engines depends heavily on modeling and simulation of a number of disciplines—neutronic / fluid / thermal / structural are only a start. Further, rockets involve extreme conditions, particularly high material temperatures in the nuclear fuel. This paper considers validation of the underling physical models and codes and how their accuracy influences several design challenges. Several issues are identified, where models, material data, could enable design solutions. In particular, thermal and CTE mismatch stresses are a concern, and stress predictions would benefit from improved mechanical property data at high temperatures. Nuclear inter-element heating causes propellant flow maldistribution and performance risks, but a simple model provides insights. High temperature chemical diffusion should be modeled to understand fuel element mass loss.

Nuclear Propulsion↗
NASA NTRS2019

Composites for Advanced Drive Systems, A Systems Analysis-Revolutionary Vertical Lift Technology (RVLT)

Rotorcraft propulsion systems are continually looking to improve power density; that is reducing weight and increasing power throughput. In order to advance rotorcraft propulsion system technology, NASA Glenn Research Center (NGRC) contracted Boeing Vertical Lift (Contract #NNA15AB12B, Task Order NNA16BE07T) to perform system level benefit assessments for incorporation of composite materials into rotorcraft transmission gear and shaft systems, in the rotating frame. In general, the environment inside a typical rotorcraft transmission is aggressive for typical composite materials. Design challenges in the rotating frame and related safety risks must be understood and accounted for in the design. Boeing developed a technical approach that evaluated a relatively large population of rotorcraft main transmissions. This technical approach took rotorcraft from various size classes and configurations and applied parametric weight estimating principles to assess the performance impact of composite hybrid technologies inside transmissions, in the rotating frame. Parametric weight estimates showed that composite hybrid technologies account for an average 9% weight savings over the baseline transmissions. More weight savings may be observed when accounting for quantity of transmissions in an aircraft configuration and benefits to airframe, landing gear, and fuel systems. A weight reduction of 595 lbs was calculated for NASA's Large Civil Tilt Rotor (LCTR2) by utilizing composite hybrid components inside the Prop-Rotor Transmission in the rotating frame and accounting for design changes to the airframe, landing gear, and fuel system. In order to develop composite hybrid technologies, sub-scale and full-scale testing should continue, building on the work that NGRC has begun. Design and testing efforts should focus on technical challenges, such as joint and attachment interfaces, temperature effects, inspection procedures, and fault detection. It is recommended to address technical challenges with targeted research and development efforts, conducted at relevant scale, prior to incorporating composite hybrid technologies within the rotating frame of helicopter transmissions.

Darmstadt, Patrick R.↗
NASA NTRS1987

Helicopter-V/STOL dynamic wind and turbulence design methodology

Aircraft and helicopter accidents due to severe dynamic wind and turbulence continue to present challenging design problems. The development of the current set of design analysis tools for a aircraft wind and turbulence design began in the 1940's and 1950's. The areas of helicopter dynamic wind and turbulence modeling and vehicle response to severe dynamic wind inputs (microburst type phenomena) during takeoff and landing remain as major unsolved design problems from a lack of both environmental data and computational methodology. The development of helicopter and V/STOL dynamic wind and turbulence response computation methology is reviewed, the current state of the design art in industry is outlined, and comments on design methodology are made which may serve to improve future flight vehicle design.

Bailey, J. Earl↗
NASA NTRS1993

Real-time automated failure identification in the Control Center Complex (CCC)

A system which will provide real-time failure management support to the Space Station Freedom program is described. The system's use of a simplified form of model based reasoning qualifies it as an advanced automation system. However, it differs from most such systems in that it was designed from the outset to meet two sets of requirements. First, it must provide a useful increment to the fault management capabilities of the Johnson Space Center (JSC) Control Center Complex (CCC) Fault Detection Management system. Second, it must satisfy CCC operational environment constraints such as cost, computer resource requirements, verification, and validation, etc. The need to meet both requirement sets presents a much greater design challenge than would have been the case had functionality been the sole design consideration. The choice of technology, discussing aspects of that choice and the process for migrating it into the control center is overviewed.

Kirby, Sarah↗
NASA NTRS2006

Propulsive maneuver design for the Mars Exploration Rover mission

Starting from approximately 150 candidate Martian landing sites, two distinct sites have been selected for further investigation by sophisticated rovers. The two rovers, named 'Spirit' and 'Opportunity', begin the surface mission respectively to Gusec Crater and Meridiani Planum in January 2004. the rovers are essentially robotic geologists, sent on a mission to research for evidence in the rocks and soil pertaining to the historical presence of water and the ability to possibly sustain life. Before this scientific search can commence, precise trajectory targeting and control is necessary to achieve the entry requirements for the selected landing sites within the constraints of the flight system. The maneuver design challenge is to meet or exceed these requirements while maintaining the necessary design flexibility to accommodate additional project concerns. Opportunities to improve performance and reduce risk based on trajectory control characteristics are also evaluated.

Opportunity↗
NASA NTRS2004

Mars Exploration Rovers Propulsive Maneuver Design

The Mars Exploration Rovers Spirit and Opportunity successfully landed respectively at Gusev Crater and Meridiani Planum in January 2004. The rovers are essentially robotic geologists, sent on a mission to search for evidence in the rocks and soil pertaining to the historical presence of water and the ability to possibly sustain life. In order to conduct NASA's 'follow the water' strategy on opposite sides of the planet Mars, an interplanetary journey of over 300 million miles culminated with historic navigation precision. Rigorous trajectory targeting and control was necessary to achieve the atmospheric entry requirements for the selected landing sites. The propulsive maneuver design challenge was to meet or exceed these requirements while preserving the necessary design margin to accommodate additional project concerns. Landing site flexibility was maintained for both missions after launch, and even after the first trajectory correction maneuver for Spirit. The final targeting strategy was modified to improve delivery performance and reduce risk after revealing constraining trajectory control characteristics. Flight results are examined and summarized for the six trajectory correction maneuvers that were planned for each mission.

trajectory↗