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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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All sourcesNASA NTRSDOE OSTI
NASA NTRS2019

NASA's Space Launch System: Deep Space Access for CubeSats

NASA is embarking on a new generation of missions to the Moon, known as the Artemis program. The Agency’s new super heavy-lift launch vehicle, the Space Launch System (SLS), is a critical enabling capability for these efforts, which will serve as a proving ground for future crewed expeditions to Mars. SLS is designed to return astronauts to the Moon in the Orion spacecraft and to launch more mass and provide more volume for critical payloads than commercially available vehicles, giving NASA a unique asset for deep space exploration. When performance margin and volume is available, as it is on the first flight, Artemis I (previously Exploration Mission-1), SLS can offer CubeSats access to deep space, beyond Earth’s orbit. The Artemis I flight has 13 6U (14 kg) CubeSats manifested, and the Program is currently accepting proposals for 6U and 12U payloads for the Artemis II flight through the agency’s CubeSat Launch Initiative (CSLI) program. Proposals from U.S.-based payload developers to fly on Artemis II will be accepted through CSLI until November 4, 2019. When ridesharing on SLS deep space missions, CubeSats must demonstrate they will not interfere with primary mission objectives. The 13 Artemis I CubeSats that hail from industry, academia, NASA and its international partners represent an array of exciting deep space science investigations and technology demonstrations that may help inform future Artemis missions. The initial SLS Block 1 vehicle for the Artemis I flight is fully manufactured; several elements are complete and have been delivered to the Exploration Ground Systems (EGS) Program at Kennedy Space Center (KSC), which has responsibility for integrating and launching the SLS and Orion stack. Completed elements of the Artemis I vehicle include the Orion Stage Adapter (OSA), which houses the 13 Artemis I CubeSats. With the Artemis I flight hardware and software nearing completion, work is in progress for the second Block 1 launcher, designated for the crewed Artemis II flight. Hardware is being manufactured for every element of the Artemis II vehicle. In this paper, the author will review the status of the Artemis I vehicle and the payloads manifested for the initial flight. Information on the Secondary Payload Deployment System (SPDS) that the SLS Program provides to payload developers will also be included.

Creech, Stephen D.↗
NASA NTRS1993

The time keeping system for GPS block IIR

The precision time keeping system (TKS) in the Global Positioning System (GPS), Block IIR satellites is designed to operate under severe natural and man made environmental conditions. The Block IIR TKS provides precise, autonomous time keeping for periods of up to seven months, without the intervention of the GPS Control Segment. The TKS is implemented using both linear and non-linear controls. The resulting TKS architecture uses a hybrid analog/digital phase locked loop (PLL). The paper provides details of the design and analysis of the TKS. The simulation techniques and the test bed activities used in performing the TKS design trade-offs are described. The effects of non-linear controls are analyzed using a TKS computer simulation of the PLL. The results from a hardware test bed are provided that verify desired TKS operation. The design criteria for the TKS computer simulation and the hardware test bed are indicated. The concepts for verification and testing of the TKS computer simulation and hardware test bed are presented.

Rawicz, H. C.↗
DOE OSTI2025

VHH antibody loop guides design of a synthetic macrocyclic peptide that potently blocks influenza virus membrane fusion

Abstract Miniaturizing biologically complex structural motifs to produce synthetic functional mimetics holds significant promise for development of new therapeutic modalities. Here, we demonstrate a unique approach using the key binding loop of the single variable domain of a heavy chain (V H H) llama antibody as a starting point for peptide design. V H H antibodies of camelids and sharks generally have longer, but more ligand-efficient complementarity determining region 3 (CDR3) loops and are relatively stable structures. We harnessed these attributes as templates for design of a series of synthetic macrocyclic peptides. The designed peptides exhibit nanomolar binding to influenza hemagglutinin (HA) and heterosubtypic in vitro neutralization breadth against influenza A viruses by inhibiting the low pH mediated HA conformational changes that lead to membrane fusion. X-ray structures of peptide-HA complexes reveal high structural mimicry with the parent V H H antibody. One such macrocycle peptide candidate is promising for further development of broad protection against influenza A group 1 viruses.

Kadam, Rameshwar U.↗
DOE OSTI2022

Benzimidazole Based Hole‐Transporting Materials for High‐performance Inverted Perovskite Solar Cells

Abstract Interfaces play a decisive role in perovskite solar cells’ power conversion efficiency and their long‐term durability. Small‐molecule hole‐transporting materials (HTMs) have grabbed enormous attention due to their structural flexibility, material properties, and stabilities, allowing for improved operational durability in perovskite photovoltaics. This study synthesizes and investigates a new class of benzimidazole‐based small molecules, named YJS001 and YJS003 , serving as the HTMs to enable high‐efficiency mixed‐cation mixed‐halide perovskite solar cells. The benzimidazole‐based materials are dopant‐free HTMs composed of donor and acceptor building blocks that are designed to engineer the energy level alignment near the HTM/perovskite interface. Mixed‐cation mixed‐halide perovskites can be grown uniformly on both HTMs with large crystalline grains. It is discovered that the donor‐rich YJS003 ‐based solar cell exhibits a high open‐circuit voltage of 1.09 V with a champion power conversion efficiency of over 20%. Power‐dependent current–voltage characteristics of the solar cells are analyzed, from which the high performance of YJS003's excellent hole mobility and well‐aligned energy level is attributed. This work introduces a new class of benzimidazole‐based small molecules as HTMs, that paves the path for dopant free interface material development for commercialization of perovskite solar cells.

14 SOLAR ENERGY↗
NASA NTRS1973

Periodic attitude control of a slowly spinning spacecraft.

A periodic attitude control system is presented which permits control of secular errors of a slowly spinning spacecraft operating in a high disturbance environment. Attitude errors of the spin-axis are detected by sun sensors (or rate gyros) and are controlled by a periodic control law which modulates external control torques generated by mass expulsion torquers. Attitude stability during the uncontrolled periods is obtained passively via the vehicle spin momentum. Equations of motion, a system block diagram, and design parameters are presented for a typical spacecraft application. Simulation results are included which demonstrate the feasibility of the novel control concept. Salient features of the periodic control approach are implementation simplicity, excellent response, and a propellant utilization efficiency greater than 75 percent.

Todosiev, E. P.↗
NASA NTRS1973

Multimegabit Operation Multiplexer System

The Multimegabit Operation Multiplexer System (MOMS) is a high-data-rate PCM telemetry unit capable of sampling and encoding 60 scanning radiometer and four vidicon channels at 250 kilosamples/second and 5 megasamples/second, respectively. This sampling capacity plus the seven-bit quantization requires a total throughput rate of 40 megasamples/second and 280 megabits/second. To produce these rates efficiently, the system was divided into a pair of identical 140-megabit blocks. A low-power 20-MHz analog multiplexer and analog-to-digital converter were developed together with a video sample-and-hold that features an aperture time error of less than 50 psec. Breadboard testing of these basic building blocks confirmed the design prediction that the total system would consume 27 watts of power. Two 140-megabit output parts are suitable for quadriphase modulation.

Giri, R. R.↗
NASA NTRS1984

Design considerations for a monolithic, GaAs, dual-mode, QPSK/QASK, high-throughput rate transceiver

A monolithic, GaAs, dual mode, quadrature amplitude shift keying and quadrature phase shift keying transceiver with one and two billion bits per second data rate is being considered to achieve a low power, small and ultra high speed communication system for satellite as well as terrestrial purposes. Recent GaAs integrated circuit achievements are surveyed and their constituent device types are evaluated. Design considerations, on an elemental level, of the entire modem are further included for monolithic realization with practical fabrication techniques. Numerous device types, with practical monolithic compatability, are used in the design of functional blocks with sufficient performances for realization of the transceiver.

Kot, R. A.↗
NASA NTRS1984

MPP disk subsystem

A disk subsystem for the Massively Parallel processor (MPP) is designed to the block diagram level. The subsystem is capable of storing 4,992 megabytes of data, expandable to 39,936 megabytes. The subsystem is capable of transferring data to the MPP Staging Memory at a rate of 25 megabytes/second, expandable to 100 megabytes/second. A lower cost disk subsystem is also presented. This alternate subsystem is capable of storing 3,744 megabytes with a transfer rate of 10.6 megabyte/second.

Hudgins, W. A.↗
NASA NTRS1986

Crash response data system for the controlled impact demonstration (CID) of a full-scale transport aircraft

A study involving the Controlled Impact Demonstration (CID) of a transport category aircraft was conducted with the objective to improve occupant safety during survivable crash scenarios. in connection with this study, the first remotely-piloted Full-Scale Transport aircraft was purposely crashed into the California desert. The program was initated to demonstrate the effectiveness of an imisting kerosene (AMK), a fuel additive emplyed to reduce postcrash fires. The unmanned CID flight carried 73 life-like flight research dummies, multiple experiments, high-speed interior cabin cameras, and the high-environment Crash Response Data System. Attention is given to the design approach, a block diagram of the Crash Response Data System, measurements, the digital data subsystem, signal conditioning, telemetry, on-board recording, the power subsystem, preflight checkout and calibration, and aspects of system qualification.

Calloway, R. S.↗
NASA NTRS1989

The role of the + or - 1 number system in multibit hardware correlators

The use of commercially available 1-bit LSI correlator chips whose main function is the correlation of sequences of plus ones and minus ones (rather than zeros and ones) as building blocks in the design of multibit correlators is investigated. A radix-2 number system in which the bit values are + or - 1 (no zero) is discussed. The development of a simple conversion algorithm to find the + or - 1 representation of a number given in 2's complement is presented. Some of the issues raised by this conversion algorithm are discussed. It is shown that, if the analog signal is available, there is a simple step to take before the analog-to-digital conversion in order to improve the overall precision. The construction of multibit correlators based on the + or - 1 system is compared to alternative approaches.

Zohar, Shalhav↗
NASA NTRS1990

Rubidium atomic frequency standards for GPS Block IIR

The Rubidium Atomic Frequency Standards (RAFS) were provided for the GPS Block IIR NAVSTAR satellites. These satellites will replenish and upgrade the space segment of the Global Positioning System in the mid 1990s. The GPS RAFS Rb clocks are the latest generation of the high-performance rubidium frequency standards. They offer an aging rate in the low pp 10(exp 14)/day range and a drift-corrected 1-day stability in the low pp 10(exp 14) range. The Block IIR version of these devices will have improved performance, higher reliability, smaller size, and greater radiation hardness. The GPS Block IIR atomic clocks have a natural frequency configuration whereby they output a frequency of about 13.4 MHz that is a submultiple of the atomic resonance of Rb (or Cs). The RAFS operates at a low, fixed C-field for increased stability. The GPS Block IIR RAFS design, including the changes and improvements made, and the test results obtained are described.

Riley, William J.↗
NASA NTRS1990

Topex/Poseidon satellite - Enabling a joint U.S.-French mission for global ocean study

A joint U.S./French mission, which represents a merging of the prior NASA Topex and CNES Poseidon progams, is described. The Topex/Poseidon satellite will contribute to two of the World Climate Research Program's phases: the World Ocean Circulation Experiment and the Tropical Ocean Global Atmosphere experiment. The satellite's instruments will measure the ocean currents and their variability on the global basis via satellite altimetry and precision orbit determinations. The paper describes the satellite configuration and characteristics and the mission instruments and system elements. The Topex/Poseidon's design diagrams and block diagrams are included.

Hall, Ralph L.↗
NASA NTRS1993

Hubble Space Telescope nickel hydrogen battery system briefing

The topics covered are presented in viewgraph form and include the following: the Hubble Space Telescope (HST) Mission; system constraints; battery specification; battery module; simplified block diagram; cell design summary; present status; voltage decay; system depth of discharge; pressure since launch; system capacity; eclipse time vs. trickle charge; capacity test objectives; and capacity during tests.

Nawrocki, David↗
NASA NTRS1992

Strain actuated aeroelastic control

Viewgraphs on strain actuated aeroelastic control are presented. Topics covered include: structural and aerodynamic modeling; control law design methodology; system block diagram; adaptive wing test article; bench-top experiments; bench-top disturbance rejection: open and closed loop response; bench-top disturbance rejection: state cost versus control cost; wind tunnel experiments; wind tunnel gust alleviation: open and closed loop response at 60 mph; wind tunnel gust alleviation: state cost versus control cost at 60 mph; wind tunnel command following: open and closed loop error at 60 mph; wind tunnel flutter suppression: open loop flutter speed; and wind tunnel flutter suppression: closed loop state cost curves.

Lazarus, Kenneth B.↗
NASA NTRS1994

VLSI neuroprocessors

Electronic and optoelectronic hardware implementations of highly parallel computing architectures address several ill-defined and/or computation-intensive problems not easily solved by conventional computing techniques. The concurrent processing architectures developed are derived from a variety of advanced computing paradigms including neural network models, fuzzy logic, and cellular automata. Hardware implementation technologies range from state-of-the-art digital/analog custom-VLSI to advanced optoelectronic devices such as computer-generated holograms and e-beam fabricated Dammann gratings. JPL's concurrent processing devices group has developed a broad technology base in hardware implementable parallel algorithms, low-power and high-speed VLSI designs and building block VLSI chips, leading to application-specific high-performance embeddable processors. Application areas include high throughput map-data classification using feedforward neural networks, terrain based tactical movement planner using cellular automata, resource optimization (weapon-target assignment) using a multidimensional feedback network with lateral inhibition, and classification of rocks using an inner-product scheme on thematic mapper data. In addition to addressing specific functional needs of DOD and NASA, the JPL-developed concurrent processing device technology is also being customized for a variety of commercial applications (in collaboration with industrial partners), and is being transferred to U.S. industries. This viewgraph p resentation focuses on two application-specific processors which solve the computation intensive tasks of resource allocation (weapon-target assignment) and terrain based tactical movement planning using two extremely different topologies. Resource allocation is implemented as an asynchronous analog competitive assignment architecture inspired by the Hopfield network. Hardware realization leads to a two to four order of magnitude speed-up over conventional techniques and enables multiple assignments, (many to many), not achievable with standard statistical approaches. Tactical movement planning (finding the best path from A to B) is accomplished with a digital two-dimensional concurrent processor array. By exploiting the natural parallel decomposition of the problem in silicon, a four order of magnitude speed-up over optimized software approaches has been demonstrated.

Kemeny, Sabrina E.↗
NASA NTRS2005

X2000 power system electronics development

The X2000 Power System Electronics (PSE) is a Jet Propulsion Laboratory (JPL) task to develop a new generation of power system building blocks for potential use on future deep space missions. The effort includes the development of electronic components and modules that can be used as building blocks in the design of generic spacecraft power systems.

X2000↗
NASA NTRS2007

Structural Analysis of the Redesigned Ice/Frost Ramp Bracket

This paper describes the interim structural analysis of a redesigned Ice/Frost Ramp bracket for the Space Shuttle External Tank (ET). The proposed redesigned bracket consists of mounts for attachment to the ET wall, supports for the electronic/instrument cables and propellant repressurization lines that run along the ET, an upper plate, a lower plate, and complex bolted connections. The eight nominal bolted connections are considered critical in the summarized structural analysis. Each bolted connection contains a bolt, a nut, four washers, and a non-metallic spacer and block that are designed for thermal insulation. A three-dimensional (3D) finite element model of the bracket is developed using solid 10-node tetrahedral elements. The loading provided by the ET Project is used in the analysis. Because of the complexities associated with accurately modeling the bolted connections in the bracket, the analysis is performed using a global/local analysis procedure. The finite element analysis of the bracket identifies one of the eight bolted connections as having high stress concentrations. A local area of the bracket surrounding this bolted connection is extracted from the global model and used as a local model. Within the local model, the various components of the bolted connection are refined, and contact is introduced along the appropriate interfaces determined by the analysts. The deformations from the global model are applied as boundary conditions to the local model. The results from the global/local analysis show that while the stresses in the bolts are well within yield, the spacers fail due to compression. The primary objective of the interim structural analysis is to show concept viability for static thermal testing. The proposed design concept would undergo continued design optimization to address the identified analytical assumptions and concept shortcomings, assuming successful thermal testing.

Phillips, D. R.↗