SEARCH · Search NASA

Results for “spacecraft elements”

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.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 163 records · Page 9

All sources NASA NTRS DOE OSTI

NASA NTRSDate not supplied

Validation of Artemis I Aerothermal Design Models Using Developmental Flight Instrumentation

The inaugural flight of the Space Launch System (SLS) Block 1 launch vehicle, Artemis I, occurred on November 16, 2022, and featured a full suite of Developmental Flight Instrumentation (DFI) that provided aerothermodynamic measurements to assess thermal design and substantiate aerothermodynamic models. The Block 1 launch vehicle aerothermal instrumentation consisted of approximately 277 aerothermal gauges mounted throughout the Orion Multi-Purpose Crew Vehicle (MPCV), Integrated Spacecraft and Payload Element (ISPE), Core Stage (CS) and Solid Rocket Boosters (SRB) and an additional 179 thermal gauges on the Orion Crew Module (CM). Instrumentation included calorimeters, radiometers, pressure transducers, gas temperature probes, and thermocouples. Data was collected from lift-off through CS Main Engine Cut-Off (MECO). The flight data was invaluable for determining aerothermal model performance and developing flight-derived aerothermal environments for flight reconstruction thermal analysis and future SLS aerothermal models. The data offered critical insights into the aerothermodynamic conditions experienced during the launch and ascent of the SLS vehicle. This study compares the flight derived environments to pre-existing design models. The aerothermal models were constructed using MINIVER, the aerothermal engineering code which predicts aerodynamic heating and acts as an integration tool for incorporating databases from computational fluid dynamics (CFD) simulations and wind tunnel test data. The comparisons reveal the fidelity of the design models, highlighting areas where the design models accurately predicted flight conditions and instances where deviations were observed. Preliminary results suggest that while the design models largely aligned with the observed flight data, there were unique observations that reflected needed areas of model refinement. Aerothermal flight data from Artemis I for the SLS Block 1 vehicle will be further utilized to enhance the accuracy of Block 1B and Block 2 aerothermal models, ensuring improved safety and performance for subsequent Artemis missions.

aerothermodynamics↗

NASA NTRS1987

Finite element model of SCOLE laboratory configuration

The Spacecraft Control Laboratory Experiment (SCOLE) is defined by element properties: material constants; mast, reflector, rigid links as beam elements; cable as bar element; and space shuttle as very stiff beam. Two boundary conditions are modeled: suspended (6 degrees of freedom for all joints except the top of the cable) and cantilevered cables (shuttle platform fixed in all degrees of freedon). Calculations include stiffness and mass matrices, initial stresses, static displacements and reactions, and eigensolutions.

Lee, Beth↗

NASA NTRS2012

Modular, Autonomous Command and Data Handling Software with Built-In Simulation and Test

The spacecraft system that plays the greatest role throughout the program lifecycle is the Command and Data Handling System (C&DH), along with the associated algorithms and software. The C&DH takes on this role as cost driver because it is the brains of the spacecraft and is the element of the system that is primarily responsible for the integration and interoperability of all spacecraft subsystems. During design and development, many activities associated with mission design, system engineering, and subsystem development result in products that are directly supported by the C&DH, such as interfaces, algorithms, flight software (FSW), and parameter sets. A modular system architecture has been developed that provides a means for rapid spacecraft assembly, test, and integration. This modular C&DH software architecture, which can be targeted and adapted to a wide variety of spacecraft architectures, payloads, and mission requirements, eliminates the current practice of rewriting the spacecraft software and test environment for every mission. This software allows missionspecific software and algorithms to be rapidly integrated and tested, significantly decreasing time involved in the software development cycle. Additionally, the FSW includes an Onboard Dynamic Simulation System (ODySSy) that allows the C&DH software to support rapid integration and test. With this solution, the C&DH software capabilities will encompass all phases of the spacecraft lifecycle. ODySSy is an on-board simulation capability built directly into the FSW that provides dynamic built-in test capabilities as soon as the FSW image is loaded onto the processor. It includes a six-degrees- of-freedom, high-fidelity simulation that allows complete closed-loop and hardware-in-the-loop testing of a spacecraft in a ground processing environment without any additional external stimuli. ODySSy can intercept and modify sensor inputs using mathematical sensor models, and can intercept and respond to actuator commands. ODySSy integration is unique in that it allows testing of actual mission sequences on the flight vehicle while the spacecraft is in various stages of assembly, test, and launch operations all without any external support equipment or simulators. The ODySSy component of the FSW significantly decreases the time required for integration and test by providing an automated, standardized, and modular approach to integrated avionics and component interface and functional verification. ODySSy further provides the capability for on-orbit support in the form of autonomous mission planning and fault protection.

Cuseo, John↗

NASA NTRS2010

A Review of International Space Station Habitable Element Equipment Offgassing Characteristics

Crewed spacecraft trace contaminant control employs both passive and active methods to achieve acceptable cabin atmospheric quality. Passive methods include carefully selecting materials of construction, employing clean manufacturing practices, and minimizing systems and payload operational impacts to the cabin environment. Materials selection and manufacturing processes constitute the first level of equipment offgassing control. An element-level equipment offgassing test provides preflight verification that passive controls have been successful. Offgassing test results from multiple International Space Station (ISS) habitable elements and cargo vehicles are summarized and implications for active contamination control equipment design are discussed

Perry, Jay L.↗

NASA NTRS1993

Resolving topographic detail on Venus by modeling complex Magellan altimetry echoes

Magellan's altimeter is providing some of the finest resolution topography of Venus achieved to date. Nevertheless, efforts continue to improve the topographic resolution whenever possible. One effort to this end is stereoscopic imaging, which provides topography at scales similar to that of the synthetic aperture radar (SAR). However, this technique requires two SAR images of the same site to be obtained and limits the utility of this method. In this paper, we present another method to resolve topographic features at scales smaller than that of an altimeter footprint, which is more globally applicable than the stereoscopic approach. Each pulse which is transmitted by Magellan's altimeter scatters from the planet and echoes to the receiver, delayed based on the distance between the spacecraft and each surface element. As resolved in time, each element of an altimetry echo represents the sum of all points on the surface which are equidistant from the spacecraft. Thus, individual returns, as a function of time, create an echo profile which may be used to derive properties of the surface, such as the scattering law or, in this case, the topography within the footprint. The Magellan project has derived some of this information by fitting model templates to radar echo profiles. The templates are calculated based on Hagfor's Law, which assumes a smooth, gently undulating surface. In most regions these templates provide a reasonable fit to the observed echo profile; however, in some cases the surface departs from these simple assumptions and more complex profiles are observed. Specifically, we note that sub-footprint topographic relief apparently has a strong effect on the shape of the echo profile. To demonstrate the effects of sub-resolution relief on echo profiles, we have calculated the echo shapes from a wide range of simple topographic models. At this point, our topographic models have emphasized surfaces where only two dominant elevations are contained within a footprint, such as graben, ridges, crater rims, and central features in impact craters.

Lovell, Amy J.↗

NASA NTRS2005

Radioisotope Electric Propulsion (REP) Spacecraft Design Concept Considerations

Radioisotopic Electric Propulsion (REP) has the potential to provide certain advantages for outer planetary exploration involving small bodies and long term investigation s for medium class missions requiring power comparable to past outer planetary exploration missions. This paper describes a preliminary conceptual design of a REP-based spacecraft where the mission of interest involves a spacecraft with a radioisotope power supply less than one kilowatt while operating at a minimum of 10-years. A key element of the REP spacecraft is to insure sustained science return by orbiting or flying in formation with selected targets. Utilizing current/impending technological advances, REP orbiter/explorer missions may provide a valuable tool for extended scientific investigations of small bodies in the outer solar system.

Edwards, Daryl A.↗

NASA NTRS2004

REP Concept Feasibility Study

Radioisotope Electric Propulsion (REP) may have the potential to provide certain advantages, over conventional chemical propulsion, for outer planetary exploration involving small bodies and long term investigations for medium class missions requiring power comparable to past outer planetary exploration missions. This paper describes a study that investigates the concept s feasibility by performing a preliminary conceptual design of an REP-based spacecraft for a design reference mission. The mission utilizes a spacecraft with a radioisotope power supply less than one kilowatt while operating for a minimum of 10-years. A key element of the REP spacecraft is to ensure sustained science return by orbiting or flying in formation with selected targets. Utilizing current and impending technological advances, this study finds that at a conceptual design level a small body REP orbiter/explorer appears to be feasible for the design reference mission selected for this study.

Edwards, Daryl A.↗

NASA NTRS1964

Overall design concepts.

Manned spacecraft design concepts covering elements in space vehicle system, interrelation of systems and design management

SPACECRAFT DESIGN↗

NASA NTRS1993

The Deep Space Network as an instrument for radio science research

Radio science experiments use radio links between spacecraft and sensor instrumentation that is implemented in the Deep Space Network. The deep space communication complexes along with the telecommunications subsystem on board the spacecraft constitute the major elements of the radio science instrumentation. Investigators examine small changes in the phase and/or amplitude of the radio signal propagating from a spacecraft to study the atmospheric and ionospheric structure of planets and satellites, planetary gravitational fields, shapes, masses, planetary rings, ephemerides of planets, solar corona, magnetic fields, cometary comae, and such aspects of the theory of general relativity as gravitational waves and gravitational redshift.

Asmar, S. W.↗

NASA NTRS1982

Study of a heat rejection system for the Nuclear Electric Propulsion (NEP) spacecraft

Two different heat pipe radiator elements, one intended for use with the power conversion subsystem of the NASA funded nuclear electric propulsion (NEP) spacecraft, and one intended for use with the DOE funded space power advanced reactor (SPAR) system were tested and evaluated. The NEP stainless steel/sodium heat pipe was 4.42 meters long and had a 1 cm diameter. Thermal performance testing at 920 K showed a non-limited power level of 3560 watts, well in excess of the design power of 2600 watts. This test verified the applicability of screen arteries for use in long radiator heat pipes. The SPAR titanium/potassium heat pipe was 5.5 meters long and had a semicircular crossection with a 4 cm diameter. Thermal performance testing at 775 K showed a maximum power level of 1.86 kW, somewhat short of the desired 2.6 kW beginning of life design requirement. The reduced performance was shown to be the result of the inability of the evaporator wall wick (shot blasted evaporator wall) to handle the required liquid flow.

Ernest, D. M.↗

NASA NTRS2011

Micro-Scale Distributions of Major and Trace Elements in Chondrites

The Hayabusa spacecraft has successfully returned to Earth after two touchdowns on the surface of Asteroid 25143 Itokawa. This asteroid is classified as an S-type and inferred to consist of materials similar to ordinary chondrites or primitive achondrites [1]. More than 1500 particles have been identified consisting of olivine, pyroxene, plagioclase, Fe sulfide and Fe metal, with compositions consistent with being of LL origin. While the chondritic components are familiar to us, the level of detail to which the Itokawa samples will be exposed to will be unprecedented given that the samples are reasonably large and accessible to a wide variety of techniques. In many ways, we expect that our knowledge base of the comparator chondrites will be found to be wanting. Chondrites are the building blocks of the solar system. However, these rocks are essentially breccias and they are quite variable in bulk element compositions as well as compositions of the individual components. We have initiated a program of analysis for chondrites focusing on major and trace element distributions between the mineral components and the matrix. The issues to be addressed include the homogeneity of matrix and chondrule components and the representivity of any given sample to the bulk meteorite. This may be particularly important given the limited numbers of Itokawa grains that may be available for a specific analysis. As an initial study, we have taken thin sections of carbonaceous chondrites to study the representivity of the matrix compositions. Spot locations were constrained to limited regions of the sections so as to assess the variability of a local scale. Further work will be required to assess variability over a centimeter scale.

Ireland, T. R.↗

NASA NTRS1966

Thermal system design of the Nimbus spacecraft.

Thermal control of Nimbus spacecraft by utilizing semipassive and passive thermal control elements to maintain temperature of overall spacecraft, subsystems and components

ELECTRONIC PACKAGING↗

NASA NTRS1967

Thermal system design of the Nimbus spacecraft.

Thermal control of Nimbus spacecraft by utilizing semipassive and passive thermal control elements to maintain temperature of overall spacecraft, subsystems and components

Drummond, F. O., Jr.↗

NASA NTRS1983

Galileo spacecraft integration - International cooperation on a planetary mission in the Shuttle era

The Galileo mission is designed to greatly expand scientific knowledge of Jupiter and its system. The retropropulsion module (RPM) as a major functional element of the Galileo spacecraft is described. The major mission and spacecraft requirements on the RPM are presented. Complexities of the integration process due to the international interface are identified. Challenges associated with integration with new launch vehicles, the Shuttle and upper stage, and their relationships to the RPM are discussed. The results of the integration process involving mission and propulsion performance, reliability, mechanical and thermal interfaces, and safety are described. Finally, considerations and recommendations for future missions involving international cooperation are given.

Spehalski, R. J.↗

NASA NTRS1992

The Galileo heavy element monitor

The Heavy Ion Counter on the Galileo spacecraft will monitor energetic heavy nuclei of the elements from C to Ni, with energies from about 6 to about 200 MeV/nucl. The instrument will provide measurements of trapped heavy ions in the Jovian magnetosphere, including those high-energy heavy ions with the potential for affecting the operation of the spacecraft electronic circuitry. The instrument, which is a modified version of the Voyager CRS instrument, is described.

Garrard, T. L.↗

NASA NTRS1977

Spacecraft subsystem checkout by minicomputer

The minicomputer, with its large capacity in a small and inexpensive package, can be an important component in special-purpose test equipment. The Voyager spacecraft flight data subsystem support equipment is an example of computer-based test gear. The subsystem to be tested is a major control and data acquisition element of the Voyager spacecraft, with a large number of interfaces to several other onboard subsystems. This equipment was designed to meet spacecraft subsystem testing requirements while making maximum use of off-the-shelf commercial components. Careful consideration was given to design tradeoffs in the areas of commercial versus specially built hardware and hardware versus software problem solutions. The resulting system is an integrated package of commercial and special-purpose hardware plus software.

Andersen, R. W.↗

NASA NTRS2004

Dynamics and Controls of a Conceptual Jovian Moon Tour Spacecraft

The dynamics and control challenges presented by a conceptual Jovian Moon Tour spacecraft are summarized in this paper. Attitude and orbital dynamics interactions are present due to the designed low-thrust trajectory, and controls structure interactions are also present due to the non-collocated sensor-actuator pairs on board the flexible spacecraft. A finite-element based simulation model is described which is capable of handling the complex orbital and attitude dynamics arising during the low-thrust spiraling maneuvers of the spacecraft. A few numerical simulations demonstrate that some of the challenges hitherto identified can be faced via integrated dynamics and control analysis, and that reasonable assessments of the pointing performance can be made.

dynamics↗

NASA NTRS1968

Communications elements research

Modified high power spacecraft antenna designs, mechanical beam steering in erectable antenna, and compressive strength properties of foam for sterilizable radiator

Source record↗