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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 109 records · Page 6
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NASA NTRSDate not supplied

Cryogenic Fluid Management Using CFD - Development and Applications

The Fluid Dynamics Branch has positioned itself to support a wide range of customers in need of Cryogenic Fluid Management (CFM) analysis. A computational fluid dynamics (CFD) tool used for all manner of internal and external propulsion applications has been extended and refined to better model cryogenic propellant storage and tanking operations. Through the CFM Portfolio project, several validation activities were initiated. Validation of propellant tank self-pressurization, autogenous pressurization, slosh-induced ullage collapse, and jet-induced mixing all aid in defining model accuracy. The on-going validation effort has enabled confident application of the tool to in-line design and evaluation of CFM hardware and operations. Recent project support included design of no-vent fill operations using various techniques for the Human Landing System (HLS). Propellant transfer dynamics were predicted to ensure complete propellant delivery. Many more activities in support of HLS and other projects and programs were supported. The branch has engaged the CFM community to share recent findings and capabilities through conferences. To reach the wider community, a consolidation of fundamental findings from work on in-space pulsed settling maneuvers was distilled in an AIAA paper. Development and demonstration of CFM modeling capabilities continues in order to meet the needs of the agency and its industry partners in the endeavor to sustainably reach the Moon and beyond.

Jacob Brodnick↗
NASA NTRSDate not supplied

Implementation of a Hybrid Edge Node-Centroid Node Approach for the Generation of Reduced Thermal Models

Reduced thermal models are often required for delivery to organizations that manage observatory or launch models at the highest levels of assembly. However, the effort to generate reduced models, and verify against their detailed counterparts, is a challenge that has not yet been conclusively solved. Higher level organizations often place a limit on the number of nodes for delivered models with the assumption that smaller models generally result in less computation time. However, the burden of producing and verifying the accuracy of the reduced models is placed primarily on the lower-level organizations, which in turn consumes resources needed to produce these models. Limiting the total number of allowable nodes may also prevent users from taking full advantage of software capabilities that allow for faster generation of models, such as finite elements, which generally require more nodes than older centroid based models. A methodology using Thermal Desktop was described in 2010 which used: (1) finite elements and edge nodes for a conduction matrix, (2) centroid nodes for capacitance and radiative computations, and (3) the super network feature to produce a conduction matrix based only on the centroid nodes. At that time, the methodology was clear, but the implementation would have had to be done manually; however, with the inclusion of the OpenTD Application Programming Interface, this methodology can now be implemented programmatically and for the first time, be a viable approach for the generation of reduced models. The approach was implemented and developed at the NASA Goddard Space Flight Center (GSFC) for the Capture, Containment, and Return System (CCRS) payload on the Earth Return Orbiter (ERO) as part of the Mars Sample Return mission, resulting in the TCYEE tool. ERO features a spacecraft bus provided by Airbus through the European Space Agency with node limitations on the delivered CCRS model provided by GSFC. TCYEE was used to generate the reduced model for this delivery and the predictions compared favorably to the detailed model currently in use for the thermal performance evaluation. Furthermore, TCYEE is being explored for potential use on the Roman Space Telescope (RST) for the generation of reduced models for delivery to the launch provider, which also has node limit requirements on the RST observatory model for use in launch simulation analyses. This paper describes the methodology, its implementation, and compares the performance of reduced models generated by TCYEE to their detailed counterparts.

Thermal Desktop↗
NASA NTRSDate not supplied

Implementation of a Hybrid Edge Node-Centroid Node Approach for the Generation of Reduced Thermal Models

Reduced thermal models are often required for delivery to organizations that manage observatory or launch models at the highest levels of assembly. However, the effort to generate reduced models, and verify against their detailed counterparts, is a challenge that has not yet been conclusively solved. Higher level organizations often place a limit on the number of nodes for delivered models with the assumption that smaller models generally result in less computation time. However, the burden of producing and verifying the accuracy of the reduced models is placed primarily on the lower-level organizations, which in turn consumes resources needed to produce these models. Limiting the total number of allowable nodes may also prevent users from taking full advantage of software capabilities that allow for faster generation of models, such as finite elements, which generally require more nodes than older centroid based models. A methodology using Thermal Desktop was described in 2010 which used: (1) finite elements and edge nodes for a conduction matrix, (2) centroid nodes for capacitance and radiative computations, and (3) the super network feature to produce a conduction matrix based only on the centroid nodes. At that time, the methodology was clear, but the implementation would have had to be done manually; however, with the inclusion of the OpenTD API, this methodology can now be implemented programmatically and for the first time, be a viable approach for the generation of reduced models. The approach was implemented and developed at the NASA Goddard Space Flight Center (GSFC) for the Capture, Containment, and Return System (CCRS) payload on the Earth Return Orbiter (ERO) as part of the Mars Sample Return (MSR) mission, resulting in the TCYEE tool. ERO features a spacecraft bus provided by Airbus through the European Space Agency (ESA) with node limitations on the delivered CCRS model provided by GSFC. TCYEE was used to generate the reduced model for this delivery and the predictions compared favorably to the detailed model currently in use for the thermal performance evaluation. Furthermore, TCYEE is being explored for potential use on the Roman Space Telescope (RST) for the generation of reduced models for delivery to the launch provider, which also has node limit requirements on the RST observatory model for use in launch simulation analyses. This paper describes the methodology, its implementation, and compares the performance of reduced models generated by TCYEE to their detailed counterparts.

Hume L. Peabody↗
NASA NTRSDate not supplied

Implementation of a Hybrid Edge Node-Centroid Node Approach for the Generation of Reduced Thermal Models

Reduced thermal models are often required for delivery to organizations that manage observatory or launch models at the highest levels of assembly. However, the effort to generate reduced models, and verify against their detailed counterparts, is a challenge that has not yet been conclusively solved. Higher level organizations often place a limit on the number of nodes for delivered models with the assumption that smaller models generally result in less computation time. However, the burden of producing and verifying the accuracy of the reduced models is placed primarily on the lower-level organizations, which in turn consumes resources needed to produce these models. Limiting the total number of allowable nodes may also prevent users from taking full advantage of software capabilities that allow for faster generation of models, such as finite elements, which generally require more nodes than older centroid based models. A methodology using Thermal Desktop was described in 2010 which used: (1) finite elements and edge nodes for a conduction matrix, (2) centroid nodes for capacitance and radiative computations, and (3) the super network feature to produce a conduction matrix based only on the centroid nodes. At that time, the methodology was clear, but the implementation would have had to be done manually; however, with the inclusion of the OpenTD API, this methodology can now be implemented programmatically and for the first time, be a viable approach for the generation of reduced models. The approach was implemented and developed at the NASA Goddard Space Flight Center (GSFC) for the Capture, Containment, and Return System (CCRS) payload on the Earth Return Orbiter (ERO) as part of the Mars Sample Return (MSR) mission, resulting in the TCYEE tool. ERO features a spacecraft bus provided by Airbus through the European Space Agency (ESA) with node limitations on the delivered CCRS model provided by GSFC. TCYEE was used to generate the reduced model for this delivery and the predictions compared favorably to the detailed model currently in use for the thermal performance evaluation. Furthermore, TCYEE is being explored for potential use on the Roman Space Telescope (RST) for the generation of reduced models for delivery to the launch provider, which also has node limit requirements on the RST observatory model for use in launch simulation analyses. This paper describes the methodology, its implementation, and compares the performance of reduced models generated by TCYEE to their detailed counterparts.

Thermal desktop↗
NASA NTRS1981

A comparison of remote sensing techniques for Minnesota wetlands classification

A wetland classification study in a typically complex 650 sq km test site in east central Minnesota compared the time, cost and accuracy of manually interpreted 1:24,000 scale color infrared aerial photographs with digital analysis of Landsat data. The comparison was between the same general wetland and non-wetland classes; accuracy of both systems was evaluated with intensive ground verification. For the same general classes, the overall mapping accuracy was 96 percent for the aerial photo interpretation and 71 percent for Landsat double-date classification. Results with maximum likelihood and SECHO classifiers were the same, 71 percent, while mapping accuracy with a layered classifier was only 66 percent. Compared to a general geometric correction and a single-date data set, geographic position and classification accuracy improved when a precision geometric correction and a double-date data set were used. Landsat digital analysis was faster, 24 vs. 90 days, but photointerpretation was more economical at $0.15/hectare (including all costs of procurement, processing and analysis), compared with Landsat costs of $0.35/hectare (not including costs of data procurement, processing prior to delivery to user and related overhead).

Werth, L. F.↗
NASA NTRS2018

SLS Block 1-B and Exploration Upper Stage Navigation System Design

The SLS Block 1B vehicle is planned to extend NASA's heavy lift capability beyond the initial SLS Block 1 vehicle. The most noticeable change for this vehicle from SLS Block 1 is the swapping of the upper stage from the Interim Cryogenic Propulsion stage (ICPS), a modified Delta IV upper stage, to the more capable Exploration Upper Stage (EUS). As the vehicle evolves to provide greater lift capability and execute more demanding missions so must the SLS Integrated Navigation System to support those missions. The SLS Block 1 vehicle carries two independent navigation systems. The responsibility of the two systems is delineated between ascent and upper stage flight. The Block 1 navigation system is responsible for the phase of flight between the launch pad and insertion into Low-Earth Orbit (LEO). The upper stage system assumes the mission from LEO to payload separation. For the Block 1B vehicle, the two functions are combined into a single system intended to navigate from ground to payload insertion. Both are responsible for self-disposal once payload delivery is achieved. The evolution of the navigation hardware and algorithms from an inertial-only navigation system for Block 1 ascent flight to a tightly coupled GPS-aided inertial navigation system for Block 1-B is described. The Block 1 GN&C system has been designed to meet a LEO insertion target with a specified accuracy. The Block 1-B vehicle navigation system is designed to support the Block 1 LEO target accuracy as well as trans-lunar or trans-planetary injection accuracy. This is measured in terms of payload impact and stage disposal requirements. Additionally, the Block 1-B vehicle is designed to support human exploration and thus is designed to minimize the probability of Loss of Crew (LOC) through high-quality inertial instruments and Fault Detection, Isolation, and Recovery (FDIR) logic. The preliminary Block 1B integrated navigation system design is presented along with the challenges associated with meeting the design objectives. This paper also addresses the design considerations associated with the use of Block 1 and Commercial Off-the-Shelf (COTS) avionics for Block 1-B/EUS as part of an integrated vehicle suite for orbital operations.

Oliver, T. Emerson↗
NASA NTRS2020

Revisiting OSIRIS-REx Touch-And-Go (TAG) Performance Given the Realities of Asteroid Bennu

The Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer (OSIRIS-REx) mission is a NASA New Frontiers mission that launched in 2016 and rendezvoused with the near-Earth asteroid (101955) Bennu in late 2018. Upon arrival, the surface of Bennu was found to be much rockier than expected. The original Touch-and-Go (TAG) requirement for sample collection was to deliver the spacecraft to a site with a 25-meter radius; however, the largest hazard-free sites are no larger than 8 meters in radius. To accommodate the dearth of safe sample collection sites, the project reevaluated all aspects of flight system performance pertaining to TAG in order to account for the demonstrated performance of the spacecraft and navigation prediction accuracies. More-over, the project has base lined on board natural feature tracking instead of lidar for providing the on board navigation state update during the TAG sequence. This paper summarizes the improvements in error source estimation, enhancements in on board trajectory correction, and results of recent Monte Carlo simulation to en-able sample collection with the given constraints. TAG delivery and on board navigation performance are presented for the final four candidate TAG sites.

Berry, Kevin↗
NASA NTRS2013

Test and Validation of the Mars Science Laboratory Robotic Arm

The Mars Science Laboratory Robotic Arm (RA) is a key component for achieving the primary scientific goals of the mission. The RA supports sample acquisition by precisely positioning a scoop above loose regolith or accurately preloading a percussive drill on Martian rocks or rover-mounted organic check materials. It assists sample processing by orienting a sample processing unit called CHIMRA through a series of gravity-relative orientations and sample delivery by positioning the sample portion door above an instrument inlet or the observation tray. In addition the RA facilitates contact science by accurately positioning the dust removal tool, Alpha Particle X-Ray Spectrometer (APXS) and the Mars Hand Lens Imager (MAHLI) relative to surface targets. In order to fulfill these seemingly disparate science objectives the RA must satisfy a variety of accuracy and performance requirements. This paper describes the necessary arm requirement specification and the test campaign to demonstrate these requirements were satisfied.

manipulation↗
NASA NTRS1983

Aerocapture and aeroassisted orbital transfer - A high performance leverage space technology

Single pass aerocapture and aeroassisted orbital transfer designs are discussed for modifying spacecraft orbits using planetary atmospheres. Aerodynamic drag can be used to shift a hyperbolic flyby trajectory to a planetary orbit by having the spacecraft altering its in-plane L/D ratio to maintain constant drag until the desired velocity is attained. The spacecraft would then move out of the atmosphere, sometimes with a small propulsive assist. Sample missions to Uranus, Jupiter, and Titan are mentioned, with mission scenarios commencing with a Shuttle launch. Biconic-shaped spacecraft are cited as having the best L/D for insertion accuracy, a low hypersonic ballistic coefficient, and volumeric efficiency. Aeroassisted orbital transfer involves atmospheric braking in order to shed velocity on a return trip from higher orbits. No decision has yet been made as to the spacecraft shape, but calculations indicate that aeroassist braking before return to LEO for rendezvous with the Shuttle has the potential for the lowest cost/mass to GEO of any delivery system currently under consideration.

Cruz, M. I.↗
NASA NTRS1996

Pulsed Plasma Thrusters for Small Spacecraft Attitude Control

Pulsed plasma thrusters (PPT's) are a new option for attitude control of a small spacecraft and may result in reduced attitude control system (ACS) mass and cost. The primary purpose of an ACS is to orient the spacecraft configuration to the desired accuracy in inertial space. The ACS functions for which the PPT system will be analyzed include disturbance torque compensation and slewing maneuvers such as sun acquisition for which the small impulse bit and high specific impulse of the PPT offers unique advantages. The NASA Lewis Reserach Center (LeRC) currently has a contracted flight PPT system development program in place with Olin Aerospace and a delivery date of October 1997. The PPT system in this study are based upon the work being done under the NASA LeRC program. Analysis of the use of PPT's for ACS showed that the replacement of the standard momentum wheels and torque rods systems with a PTT system to perform the altitude control maneuvers on a small low Earth orbiting spacecraft reduced the ACS mass by 50 to 75 percent with no increase in required power level over comparable wheel-based systems.

McGuire, Melissa L.↗
NASA NTRS1996

Pulsed plasma thrusters for small spacecraft attitude control

Pulsed Plasma Thrusters (PPTS) are a new option for attitude control of a small spacecraft and may result in reduced attitude control system (ACS) mass and cost. The primary purpose of an ACS is to orient the spacecraft to the desired accuracy in inertial space. The ACS functions for which the PPT system will be analyzed include disturbance torque compensation, and slewing maneuvers such as sun acquisition for which the small impulse bit and high specific impulse of the PPT offers unique advantages. The NASA Lewis Research Center (LERC) currently has a contracted flight PPT system development program in place with Olin Aerospace with a delivery date of October 1997. The PPT systems in this study are based upon the work being done under the NASA LERC program. Analysis of the use of PPTs for ACS showed that the replacement of the standard momentum wheels and torque rods with a PPT system to perform the attitude control maneuvers on a small low Earth orbiting spacecraft reduced the ACS mass by 50 to 75% with no increase in required power level over comparable wheel-based systems, though rapid slewing power requirements may present an issue.

McGuire, Melissa L.↗
NASA NTRS1998

Automated pH Control of Nutrient Solution in a Hydroponic Plant Growth System

Over, the years, NASA has played an important role in providing to and the development of automated nutrient delivery and monitoring, systems for growing crops hydroponically for long term space missions. One example are the systems used in the Biomass Production Chamber (BPC) at Kennedy Space Center (KSC). The current KSC monitoring system is based on an engineering workstation using standard analog/digital input/output hardware and custom written software. The monitoring system uses completely separate sensors to provide a check of control sensor accuracy and has the ability to graphically display and store data form past experiment so that they are available for data analysis [Fortson, 1992]. In many cases, growing systems have not been fitted with the kind of automated control systems as used at KSC. The Center for Food and Environmental Systems for Human Exploration of Space (CFESH) located on the campus of Tuskegee University, has effectively grown sweetpotatoes and peanuts hydroponically for the past five years. However they have adjusted the pH electrical conductivity and volume of the hydroponic nutrient solution only manually at times when the solution was to be replenished or changed out according to its protocol (e.g. one-week, two-week, or two-day cycle). But the pH of the nutrient solution flowing through the channel is neither known nor controlled between the update, change out, or replenishment period. Thus, the pH of the nutrient solution is not held at an optimum level over the span of the plant's growth cycle. To solve this dilemma, an automated system for the control and data logging of pH data relative to sweetpotato production using the nutrient film technique (NFT) has been developed, This paper discusses a microprocessor-based system, which was designed to monitor, control, and record the pH of a nutrient solution used for growing sweetpotatoes using NFT.

Smith, B.↗
NASA NTRS2020

ELEET- Formulating a Multi-Element, Inter-agency Error Budget for Robust Earth Entry of Returned Mars Samples

The operational segment of a potential Mars Sample Return campaign could end with final delivery of the Earth Entry System to the surface of Earth, punctuating an impressive international collaboration on multiple flight elements over many years. A comprehensive error budget approach is presented to characterize the high-dimensional technical challenge of this concept, including inputs from interdisciplinary stakeholders. Effects considered include interplanetary navigation, spacecraft attitude and maneuver control, and entry environment, culminating in figures of merit such as landing range accuracy. Broad tradespace exploration confirms some intuitions while challenging others, and a set of solutions are identified that are mutually agreeable to NASA and ESA.

Lobbia, Marcus↗
NASA NTRS1995

SXI prototype mirror mount

The purpose of this contract was to provide optomechanical engineering and fabrication support to the Solar X-ray Imager (SXI) program in the areas of mirror, optical bench and camera assemblies of the telescope. The Center for Applied Optics (CAO) worked closely with the Optics and S&E technical staff of MSFC to develop and investigate the most viable and economical options for the design and fabrication of a number of parts for the various telescope assemblies. All the tasks under this delivery order have been successfully completed within budget and schedule. A number of development hardware parts have been designed and fabricated jointly by MSFC and UAH for the engineering model of SXI. The major parts include a nickel electroformed mirror and a mirror mount, plating and coating of the ceramic spacers, and gold plating of the contact rings and fingers for the camera assembly. An aluminum model of the high accuracy sun sensor (HASS) was also designed and fabricated. A number of fiber optic tapers for the camera assembly were also coated with indium tin oxide and phosphor for testing and evaluation by MSFC. A large number of the SXI optical bench parts were also redesigned and simplified for a prototype telescope. These parts include the forward and rear support flanges, front aperture plate, the graphite epoxy optical bench and a test fixture for the prototype telescope. More than fifty (50) drawings were generated for various components of the prototype telescope. Some of these parts were subsequently fabricated at UAH machine shop or at MSFC or by the outside contractors. UAH also provide technical support to MSFC staff for a number of preliminary and critical design reviews. These design reviews included PDR and CDR for the mirror assembly by United Technologies Optical Systems (UTOS), and the program quarterly reviews, and SXI PDR and CDR. UAH staff also regularly attended the monthly status reviews, and made a significant number of suggestions to improve the design, assembly and alignment of the telescope. Finally, a high level assembly and alignment plan for the entire telescope was prepared by UAH. This plan addresses the sequence of assembly, the required assembly and alignment tolerances, and the methods to verify the alignment at each step during the assembly process. This assembly and alignment plan will be used to assemble and integrate the engineering model (EM) of the telescope. Later on, based on this plan more detailed assembly and alignment procedures will be developed for the lower-level assemblies of SXI.

Source record↗
NASA NTRS2000

Recent Cycle Time Reduction at Langley Research Center

The NASA Langley Research Center (LaRC) has been engaged in an effort to reduce wind tunnel test cycle time in support of Agency goals and to satisfy the wind tunnel testing needs of the commercial and military aerospace communities. LaRC has established the Wind Tunnel Enterprise (WTE), with goals of reducing wind tunnel test cycle time by an order of magnitude by 2002, and by two orders of magnitude by 2010. The WTE also plans to meet customer expectations for schedule integrity, as well as data accuracy and quality assurance. The WTE has made progress towards these goals over the last year with a focused effort on technological developments balanced by attention to process improvements. This paper presents a summary of several of the WTE activities over the last year that are related to test cycle time reductions at the Center. Reducing wind tunnel test cycle time, defined here as the time between the freezing of loft lines and delivery of test data, requires that the relationship between high productivity and data quality assurance be considered. The efforts have focused on all of the drivers for test cycle time reduction, including process centered improvements, facility upgrades, technological improvements to enhance facility readiness and productivity, as well as advanced measurement techniques. The application of internet tools and computer modeling of facilities to allow a virtual presence of the customer team is also presented.

Kegelman, Jerome T.↗
NASA NTRS1991

The MARCOR GPS mobile data system

Market research revealed several key demands for an Automatic Vehicle Location (AVL) Global Positioning System (GPS) radio. The demands were for minimization of urban building blockage, easy programmability to minimize mobile data transmission costs, high accuracy for street map level coordination, interface capability with non-digital Specialized Mobile Radios (SMR), and a selling price close to that of alternatives such as Signposts and Loran-C. A team of experts was assembled to surmount these challenges and deliver a GPS radio for $500 to $1000, which operates at high accuracy in an urban environment and is plug-compatible with nearly all vehicle radios. Among the engineering and production breakthroughs described here are a unique Simultrac (Trademark) approach to satellite tracking, enabling up to eight GPS satellites to be used for position determination with a 2-channel receiver, and a receiver-in-a-microphone design. A powerful Application Specific Integrated Circuit (ASIC) allowed GPS to be brought within easy reach of millions of AVL users such as bus, taxi, and delivery vehicle fleets.

Rothblatt, Martin↗
NASA NTRS2004

A Novel Spacecraft Charge Monitor for LEO

Five years ago we introduced a new method for measuring spacecraft chassis floating potential relative to the space plasma (absolute spacecraft potential) in low Earth orbit. The method, based on a straightforward interpretation of photoelectron spectra, shows promise for numerous applications, but has not yet been tried. In the interest of testing the method, and ultimately supplying another tool for measuring absolute spacecraft charge, we are producing a flight prototype Spacecraft Charge Monitor (SCM) with support from NASA's Small Business Innovation Research (SBIR) program. Although insight into the technique came from data collected in space over two decades ago, very little data are available. The data indicate that it may be possible to determine spacecraft floating potential to within 0.1 volt each with the SCM second under certain conditions. It is debatable that spacecraft floating potential has ever been measured with such accuracy. The compact, easily deployed SCM also offers the advantage of long-term stability in calibration. Accurate floating potential determinations from the SCM could be used to correct biases in space plasma measurements and evaluate charge mitigation and/or sensing devices. Although this paper focuses on the device's use in low Earth orbit (LEO), the device may also be able to measure spacecraft charge at higher altitudes, in the solar wind, and in orbits around other planets. The flight prototype SCM we are producing for delivery to NASA in the third quarter of 2004 will measure floating potential from 0 to -150 volts with 0.1 volt precision, weigh approximately 600-700 grams, consume approximately 2 watts, and will measure approximately 8 x 10 x 17 cm.

Goembel, Luke↗
NASA NTRS2019

Modern Aerocapture Guidance to Enable Reduced-Lift Vehicles at Neptune

Aerocapture is covered extensively in the literature as means of achieving orbital insertion with dramatic mass-saving results compared to fully-propulsive systems. One of the primary obstacles facing aerocapture is the inherent uncertainty associated with passing through a planet’s upper atmosphere. In-flight dispersions due to delivery errors, environment variables, and aerodynamic performance impose a large flight envelope. System studies for aerocapture often select high lift-to-drag ratios to compensate for these uncertainties. However, modern predictor-corrector guidance strategies have shown promise in recent years to provide robust control schemes in-situ. These algorithms do not rely on a pre-calculated reference trajectory and instead employ a numerical optimizer to continuously solve nonlinear equations of motion each guidance cycle. Numerical predictor-corrector strategies may provide considerable accuracy over heritage guidance schemes. The goal of this study is reproduce a landmark study of Neptune aerocapture and apply modern guidance to illustrate relative performance improvements and cost-saving potential. Capture constraints based on the theoretical corridor width are considered. Results indicate that heritage vehicles with moderate lift-to-drag ratios, lower than previous studies have indicated, may prove viable for aerocapture at Neptune.

Heidrich, C. R.↗