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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 1,549 records · Page 86
All sourcesNASA NTRSDOE OSTI
NASA NTRS1985

Tethers Open New Space Options

The fundamentals of tether action are discussed with focus on the forces acting on tethered masses and a tethered satellite system being developed for deployment from the space shuttle is examined. The static, dynamic, and electric properties of the tether can be exploited for use in the long term observation of phenomena of the lower troposphere; as a space based wind tunnel; to generate high electrodynamic power; to provide desirable gravity for the space station; to dock orbit transfer vehicles with the space station; and to form a constellation of space platforms tied to the space station. Italy is responsible for building and integrating the satellite. NASA is involved in building the deployer and integrating the tethered satellite system with the space shuttle.

Bekey, I.↗
NASA NTRS1986

Space Station tethered refueling facility operations

The space-based orbital transfer vehicle will require a large cryogenic fuel storage facility at the Space Station. An alternative to fuel storage onboard the Space Station, is on a tethered orbital refueling facility (TORF) which is separated from the Space Station by a sufficient distance to induce a gravity gradient to settle the propellants. Facility operations are a major concern associated with a tethered LO2/LH2 storage depot. A study was carried out to analyze these operations so as to identify the preferred TORF deployment direction (up or down) and whether the TORF should be permanently or intermittently deployed. The analyses considered safety, contamination, rendezvous, servicing, transportation rate, communication, and viewing. An upwardly, intermittently deployed facility is the preferred configuration for a tethered cryogenic fuel storage.

Kiefel, E. R.↗
NASA NTRS1986

Comparison of a tethered to a zero-gravity refueling facility

The space-based orbital transfer vehicle will require a large cryogenic fuel storage facility at the Space Station. An alternative to fuel storage on-board the Space Station is on a tethered orbital refueling facility (TORF) which is separated from the Space Station by a sufficient distance to induce a gravity gradient to settle the propellants. Overall costs and benefits of a particular tethered facility design have been defined relative to a representative zero-gravity facility on the Space Station. Results indicate that the TORF hardware and operations costs are roughly 40 percent higher than the comparable zero-g facility costs. The cost difference is negligible when compared to the launch cost of the fuel over the facility 10-year lifetime.

Kiefel, E. R.↗
NASA NTRS1988

Tethered versus attached cryogenic propellant storage at Space Station

The space-based orbital transfer vehicle will require a large cryogenic fuel storage facility at the Space Station. An alternative to fuel storage on-board the Space Station is on a tethered orbital refueling facility (TORF) which is separated from the Space Station by a sufficient distance to induce a gravity gradient to settle the propellants. Overall costs and benefits of a particular tethered facility design have been defined relative to a representative zero-gravity facility on the Space Station. Results indicate that the TORF hardware and operations costs are roughly 40 percent higher than the comparable zero-g facility costs. The cost difference is negligible when compared to the launch cost of the fuel over the facility 10-year lifetime.

Fester, Dale A.↗
NASA NTRS1996

Thermal Control Subsystem Design for the Avionics of a Space Station Payload

A case study of the thermal control subsystem development for a space based payload is presented from the concept stage through preliminary design. This payload, the Space Acceleration Measurement System 2 (SAMS-2), will measure the acceleration environment at select locations within the International Space Station. Its thermal control subsystem must maintain component temperatures within an acceptable range over a 10 year life span, while restricting accessible surfaces to touch temperature limits and insuring fail safe conditions in the event of loss of cooling. In addition to these primary design objectives, system level requirements and constraints are imposed on the payload, many of which are driven by multidisciplinary issues. Blending these issues into the overall system design required concurrent design sessions with the project team, iterative conceptual design layouts, thermal analysis and modeling, and hardware testing. Multiple tradeoff studies were also performed to investigate the many options which surfaced during the development cycle.

Moran, Matthew E.↗
NASA NTRS1994

Transient Numerical Modeling of the Combustion of Bi-Component Liquid Droplets: Methanol/Water Mixture

This study shows that liquid mixtures of methanol and water are attractive candidates for microgravity droplet combustion experiments and associated numerical modeling. The gas phase chemistry for these droplet mixtures is conceptually simple, well understood and substantially validated. In addition, the thermodynamic and transport properties of the liquid mixture have also been well characterized. Furthermore, the results obtained in this study predict that the extinction of these droplets may be observable in ground-based drop to tower experiments. Such experiments will be conducted shortly followed by space-based experiments utilizing the NASA FSDC and DCE experiments.

Marchese, A. J.↗
NASA NTRS2007

Gravitational Waves: Elusive Cosmic Messengers

The final merger of two black holes is expected to be the strongest g ravitational wave source for ground-based interferometers such as LIG O, VIRGO, and GE0600, as well as the space-based interferometer LISA. Observing these sources with gravitational wave detectors requires t hat we know the radiation waveforms they emit. Since these mergers ta ke place in regions of extreme gravity, we need to solve Einstein's equations of general relativity on a computer in order to calculate t hese waveforms. For more than 30 years, scientists have tried to comp ute black hole mergers using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could comple te even a single orbit. Within the past few years, however, this situ ation has changed dramatically, with a series of remarkable breakthro ughs. This talk will focus on new simulations that are revealing the dynamics and waveforms of binary black hole mergers, and their applic ations in gravitational wave detection, data analysis, and astrophysi cs.

Centrella, Joan↗
NASA NTRS2009

CRYOTE (Cryogenic Orbital Testbed) Concept

Demonstrating cryo-fluid management (CFM) technologies in space is critical for advances in long duration space missions. Current space-based cryogenic propulsion is viable for hours, not the weeks to years needed by space exploration and space science. CRYogenic Orbital TEstbed (CRYOTE) provides an affordable low-risk environment to demonstrate a broad array of critical CFM technologies that cannot be tested in Earth's gravity. These technologies include system chilldown, transfer, handling, health management, mixing, pressure control, active cooling, and long-term storage. United Launch Alliance is partnering with Innovative Engineering Solutions, the National Aeronautics and Space Administration, and others to develop CRYOTE to fly as an auxiliary payload between the primary payload and the Centaur upper stage on an Atlas V rocket. Because satellites are expensive, the space industry is largely risk averse to incorporating unproven systems or conducting experiments using flight hardware that is supporting a primary mission. To minimize launch risk, the CRYOTE system will only activate after the primary payload is separated from the rocket. Flying the testbed as an auxiliary payload utilizes Evolved Expendable Launch Vehicle performance excess to cost-effectively demonstrate enhanced CFM.

Gravlee, Mari↗
NASA NTRS2010

Moving Toward Space Internetworking via DTN: Its Operational Challenges, Benefits, and Management

The international space community has begun to recognize that the established model for management of communications with spacecraft - commanded data transmission over individual pair-wise contacts - is operationally unwieldy and will not scale in support of increasingly complex and sophisticated missions such as NASA's Constellation project. Accordingly, the international Inter-Agency Operations Advisory Group (IOAG) ichartered a Space Internetworking Strategy Group (SISG), which released its initial recommendations in a November 2008 report. The report includes a recommendation that the space flight community adopt Delay-Tolerant Networking (DTN) to address the problem of interoperability and communication scaling, especially in mission environments where there are multiple spacecraft operating in concert. This paper explores some of the issues that must be addressed in implementing, deploying, and operating DTN as part of a multi-mission, multi-agency space internetwork as well as benefits and future operational scenarios afforded by DTN-based space internetworking.

Delay Tolerant Networking↗
NASA NTRSDate not supplied

Experimental Results from Integrated LCRD Low-Earth Orbit User Modem and Amplifier Terminal (ILLUMA-T) Program

The National Aeronautics and Space Administration’s (NASA) Integrated LCRD Low-Earth Orbit (LEO) User Modem and Amplifier Terminal (ILLUMA-T) payload was launched and installed on the International Space Station’s (ISS) Japanese Experiment Module - Exposed Facility (JEM-EF) in November 2023. ILLUMA-T was the first space-based user to communicate with NASA’s Laser Communications Relay Demonstration (LCRD) using free space optical communication to transfer data from the ISS at return rates to Earth of up to 1.244 Gbps and forward rates from Earth of up to 155 Mbps. A 6-month long Experiments Program on ILLUMA-T concluded in June 2024, after which the payload was removed from the ISS and is currently de-orbiting. The Experiments Program was carefully designed to understand and characterize the Pointing, Acquisition, and Track (PAT) process with the new Modular, Agile, Scalable Optical Terminal (MAScOT), optical modem performance, and end-to-end relay performance.

ISS↗
NASA NTRS1991

NASA's advanced space transportation system launch vehicles

Some insight is provided into the advanced transportation planning and systems that will evolve to support long term mission requirements. The general requirements include: launch and lift capacity to low earth orbit (LEO); space based transfer systems for orbital operations between LEO and geosynchronous equatorial orbit (GEO), the Moon, and Mars; and Transfer vehicle systems for long duration deep space probes. These mission requirements are incorporated in the NASA Civil Needs Data Base. To accomplish these mission goals, adequate lift capacity to LEO must be available: to support science and application missions; to provide for construction of the Space Station Freedom; and to support resupply of personnel and supplies for its operations. Growth in lift capacity must be time phased to support an expanding mission model that includes Freedom Station, the Mission to Planet Earth, and an expanded robotic planetary program. The near term increase in cargo lift capacity associated with development of the Shuttle-C is addressed. The joint DOD/NASA Advanced Launch System studies are focused on a longer term new cargo capability that will significantly reduce costs of placing payloads in space.

Branscome, Darrell R.↗
NASA NTRS2013

The Lunar Laser OCTL Terminal (LLOT) Optical Systems

The Lunar Laser OCTL Terminal is an auxiliary ground station terminal for the Lunar Laser Communication Demonstration (LLCD). The LLOT optical systems exercise modulation and beam divergence control over six 10-watt fiber-based laser transmitters at 1568 nanometers, which act as beacons for pointing of the space-based terminal. The LLOT design transmits these beams from distinct sub-apertures of the F/76 OCTL telescope at divergences ranging from 110 microrad to 40 microrad. LLOT also uses the same telescope aperture to receive the downlink signal at 1550 nanometers from the spacecraft terminal. Characteristics and control of the beacon lasers, methods of establishing and maintaining beam alignment, beam zoom system design, co-registration of the transmitted beams and the receive field of view, transmit/receive isolation, and downlink signal manipulation and control are discussed.

laser communications↗
NASA NTRSDate not supplied

TPSAS-NF1676L-18612-DND

Can a space-based elastic backscatter lidar and coincident infrared radiometer recognize the varied microphysical properties observed by aircraft-based cloud probes in cirrus clouds? If so, then the global and continuous coverage provided by the satellite instruments can extend the knowledge about cirrus cloud properties gained from intensive aircraft field campaigns. The recent Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) aircraft field mission that occurred during August and September, 2013 is an ideal data set to use to test whether this is possible. During SEAC4RS there was extensive sampling of cirrus clouds occurring in widely varied conditions, including the North American Monsoon, forest fires, midlatitude frontal convection and tropical convection. Aircraft cloud probe sampling (2D-S, FCDP or FSSP, CPI) was performed from three airplanes, often coordinated with remote sensing by an aircraft-based elastic backscatter lidar (CPL). During the mission the CALIPSO satellite also observed these clouds from space with a similar elastic backscatter lidar (CALIOP) and an infrared radiometer (IIR). There are several cases where the airplanes sampled directly along the satellite track, but also many overpasses of the region and these features that were not coincident with the aircraft-based sampling. This presentation seeks to address the question of whether relationships between the cloud particle size distribution measurements and habits observed by the SPEC cloud probes and CPL aircraft lidar parameters can be up-scaled to classify the CALIPSO satellite observations from this region and time period. The lidar can also provide cloud top information and evidence of whether there was irreversible transport of ice and aerosols into the UT/LS.

Melody Avery↗
NASA NTRS1990

TROUBLE 3: A fault diagnostic expert system for Space Station Freedom's power system

Designing Space Station Freedom has given NASA many opportunities to develop expert systems that automate onboard operations of space based systems. One such development, TROUBLE 3, an expert system that was designed to automate the fault diagnostics of Space Station Freedom's electric power system is described. TROUBLE 3's design is complicated by the fact that Space Station Freedom's power system is evolving and changing. TROUBLE 3 has to be made flexible enough to handle changes with minimal changes to the program. Three types of expert systems were studied: rule-based, set-covering, and model-based. A set-covering approach was selected for TROUBLE 3 because if offered the needed flexibility that was missing from the other approaches. With this flexibility, TROUBLE 3 is not limited to Space Station Freedom applications, it can easily be adapted to handle any diagnostic system.

Manner, David B.↗
NASA NTRS1983

Space station needs, attributes, and architectural options study

The top level, time-phased total space program support system architecture is described including progress from the use of ground-based space shuttle, teleoperator system, extended duration orbiter, and multimission spacecraft, to an initial 4-man crew station at 29 deg inclination in 1991, to a growth station with an 8-man crew with capabilities for OTV high energy orbit payload placement and servicing, assembly, and construction of mission payloads in 1994. System Z, proposed for Earth observation missions in high inclination orbit, can be accommodated in 1993 using a space station derivative platform. Mission definition, system architecture, and benefits are discussed.

Source record↗
NASA NTRS1989

Optical interferometers for tests of relativistic gravity in space

A space-based astrometric interferometer with a large optical bandwidth is considered. POINTS (Precision Optical INTerferometry in Space) would measure the angular separation of two stars separated by about 90 deg on the sky with a nominal measurement error of 5 microarcseconds (mas). For a pair of mag 10 stars, the observation would require about 10 minutes. It is estimated that the instrument would measure daily the separation of two stars for each of about 60 pairs of stars; a random sequence of such measurements, if suitably redundant, contains the closure information necessary to detect and correct time dependent measurement biases to well below the nominal measurement accuracy. The 90 deg target separation permits absolute parallax measurements in all directions. A redundant observing schedule for 300 stars and 5 quasars would provide extra redundancy to compensate for the quasars' higher magnitude. If a nominal 30-day observation sequence were repeated 4 times per year for 10 years, stellar parameter uncertainties would be obtained of: 0.6 mas, position; 0.4 mas/y, proper motion; and 0.4 mas, parallax. This set of well-observed stars and quasars would form a rigid frame and the stars would serve as reference objects for measurements of all additional targets, as well as being targets of direct scientific interest. The instrument global data analysis since objectives are considered including a relativity test and technology.

Reasenberg, R. D.↗
NASA NTRS1990

Tensile properties of HA 230 and HA 188 after 400 and 2500 hour exposures to LiF-22CaF2 and vacuum at 1093 K

The solid-to-liquid phase transformation of the nominal LiF-20CaF2 eutectic at 1043 K is considered to be an ideal candidate thermal energy storage mechanism for a space based low temperature Brayton cycle solar dynamic system. Although Co, Fe, and Ni superalloys are thought to be suitable containment materials for LiF based salts, long term containment is of concern because molten fluorides are usually corrosive and Cr can be lost into space through evaporation. Two examples of commercially available superalloys in sheet form, the Ni-base material HA 230 and the Co-base material Ha 88, have been exposed to molten LiF-22CaF2, its vapor, and vacuum, at 1093 K, for 400 and 2500 hr. Triplicate tensile testing of specimens subjected to all three environments have been undertaken between 77 to 1200 K. Comparison of the weight gain data, microstructure, and tensile properties indicate that little, if any, difference in behavior can be ascribed to the exposure environment.

Whittenberger, J. Daniel↗
NASA NTRS1992

The EOS Data and Information System (EOSDIS)

The Earth Observing System (EOS) is the centerpiece of NASA's Mission to Planet Earth initiative. It is a pivotal part of the U.S. Global Change Research Program and hence of the international effort to understand global change and the increasing demands of human activity. EOS consists of a space-based observing system, a Data and Information System (EOSDIS) and a scientific research program. The space component consists of two series of polar-orbiting spacecraft, the first scheduled for launch in 1998, that will collect data for 15 years. EOS is completing its conceptual design phase and is preparing to enter the design phase with the selection and construction of the instruments for the first platform. EOSDIS will allow researchers to quickly and easily access data about the Earth system. Development of EOSDIS has already begun; it will support research and analysis with existing data. Geophysical and biological products will be created from the satellite data to be used to a broad range of the scientific community. NASA has also committed to providing smaller missions - called Earth Probes - dedicated to near-term observations of specific Earth processes. The scientific research program was initiated in 1990, with funding for 28 interdisciplinary teams, to begin development of models that will use EOS data and define the data requirements from the instruments, nine facility instruments and their science teams, 23 instrument investigations and definition studies for a synthetic-aperture radar.

Dozier, J.↗