Optimized silicon solar cells for space exploration power systems
Optimized silicon solar cells for space exploration power systems
Iles, P. A.↗
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Small Stirling Technology Exploration Power for Future Space Science Missions
High efficiency dynamic Radioisotope Power Systems (RPS) could be mission enabling for low power space applications such as small probes, landers rovers, and communication repeaters. These applications would contain science instruments and be distributed across planetary surfaces or near objects of interest where solar flux is insufficient for using solar cells. Small RPS could be used to provide power for sensing radiation, temperature, pressure, seismic activity, and other measurements of interest to planetary scientists. Small RPS would use fractional versions of the General Purpose Heat Source (GPHS) or Light Weight Radioisotope Heater Units (LWRHU), to heat power conversion technologies. Dynamic power systems are capable of three to four times higher conversion efficiency compared to static power conversion technologies, and would provide an equal amount of power using less fuel or more power using an equal amount of fuel. Providing spacecraft with more power could decrease duty cycling of basic functions and, therefore, increase the quality and abundance of science data. NASA GRC is developing a low power dynamic RPS that would convert heat from multiple LWRHU to one watt of usable direct current electric power for spacecraft instrumentation and communication. The power system could be used to charge batteries or capacitors for higher power burst usage. The initial design, called Small Stirling Technology Exploration Power (smallSTEP), is around 3 kg, 11 cm diameter X 32 cm long, and converts 8 watts of heat to one watt of electricity using a Stirling convertor. This low power conversion system represents a new class of RPS with power levels two orders of magnitude lower than prototypes currently being developed for space applications under NASA contracts. Development of the 1-watt RPS includes maturation of convertor and controller designs, performance evaluation of an evacuated metal foil insulation, and development of system interfaces. Initial demonstration of the subsystems has been completed in a laboratory environment and a higher fidelity system is being pursued for demonstration in relevant environments for use on small spacecraft needed to carry out future space science missions.
Wilson, Scott D.↗
Small Stirling Technology Exploration Power for Future Space Science Missions
High efficiency dynamic Radioisotope Power Systems (RPS) could be mission enabling for low power space applications such as small probes, landers rovers, and communication repeaters. These applications would contain science instruments and be distributed across planetary surfaces or near objects of interest where solar flux is insufficient for using solar cells. Small RPS could be used to provide power for sensing radiation, temperature, pressure, seismic activity, and other measurements of interest to planetary scientists. Small RPS would use fractional versions of the General Purpose Heat Source (GPHS) or Light Weight Radioisotope Heater Units (LWRHU), to heat power conversion technologies. Dynamic power systems are capable of three to four times higher conversion efficiency compared to static power conversion technologies, and would provide an equal amount of power using less fuel or more power using an equal amount of fuel. Providing spacecraft with more power could decrease duty cycling of basic functions and, therefore, increase the quality and abundance of science data. NASA Glenn Research Center (GRC) is developing a low power dynamic RPS that would convert heat from multiple LWRHU to one watt of usable direct current electric power for spacecraft instrumentation and communication. The power system could be used to charge batteries or capacitors for higher power burst usage. The initial design, called Small Stirling Technology Exploration Power (smallSTEP), is around 3 kg, 11 cm diameter X 32 cm long, and converts 8 watts of heat to one watt of electricity using a Stirling convertor. This low power conversion system represents a new class of RPS with power levels two orders of magnitude lower than prototypes currently being developed for space applications under NASA contracts. Development of the 1-watt RPS includes maturation of convertor and controller designs, performance evaluation of an evacuated metal foil insulation, and development of system interfaces. Initial demonstration of the subsystems has been completed in a laboratory environment and a higher fidelity system is being pursued for demonstration in relevant environments for use on small spacecraft needed to carry out future space science missions.
Wilson, Scott↗
The Small Explorer power system
A direct-energy-transfer (DET) power system design with the battery connected directly to the bus was selected as the generic power system to satisfy the various Small Explorer spacecraft missions. The power system electronics (PSE) are designated to handle power levels up to a 250-W load with minimum changes in the electronics. The command and telemetry interface is through an optical MIL-STD-1773 interface that is contained in the PSE. The system provides high performance, low weight, and low EMI (electromagnetic interference) generation. The design and performance of the power system have been verified through analysis and extensive tests on a breadboard.
Dakermanji, George↗
The Atmosphere Explorer power subsystem
The design and operation of the power subsystem for the Atmospheric Explorer spacecraft are discussed. The additional functional redundancy which was added in several component areas to improve the overall subsystem reliability is analyzed. The battery charging technique has been modified to include third electrode overcharge control. The automatic removal of all battery charge is provided to correct abnormally high battery voltages. An undervoltage detector has been added which removes all nonessential spacecraft loads when the battery voltage falls below a given level. All automatic functions can be over-ridden by ground command.
Obenschain, A.↗
The Small Explorer power system electronics
The power system electronics for the NASA Goddard Space Flight Center Small Explorer Satellites are intended to satisfy various planned missions. The selected topology is a direct energy transfer (DET) system with the battery connected directly to the bus. The shunt control technique is a linear sequential full shunt which provides a simple solar array interface and can support both 3 axis stabilized and spinner satellites. In addition, it can meet stringent electromagnetic interference requirements which are expected on some Small Explorer Missions. The Power Systems Electronics (PSE) performs battery charge control using both temperature compensated charge/discharge ratio ampere hour integration and voltage-temperature control. The PSE includes all the circuits needed to perform telemetry and command functions using an optical MIL-STD-1773 interface.
Dakermanji, G.↗
The Atmosphere Explorer power subsystem
The present work describes the design and in-flight performance of the power subsystem for the first three Atmosphere Explorer (AE) spacecraft. The subsystem provides all electrical power to the spacecraft loads and consists of a solar array, three batteries, and a power supply electronics unit. Power from the solar array is supplied to the spacecraft loads through an unregulated power bus, which varies between -26 and -38 V. Loads which are normally on only during data collection phases of an orbit are fed from a tightly regulated -24.5 V bus. Power subsystem performance during the first three months in orbit has been nominal, except for an anomally in the shunt limiter protection circuitry. A malfunctioning shunt control amplifier was reconnected via ground command.
Obenschain, A.↗
Design and performance of the International Sun-Earth Explorer power systems
The launches of the International Sun-Earth Explorers in October 1977 (ISEE-A) and August 1978 (ISEE-C) marked the first successful implementation of an electrostatically clean spacecraft design on a US-built satellite. The power subsystem design selected was required to operate without induced or coupled electromagnetic interference while meeting the criteria of low cost, low weight (with the resulting removal of almost all redundancy), modular construction techniques, long life (more than 3 years), and maximum utilization of previously qualified/flown designs. To save money, both the ISEE-A and -C power subsystem designs had to be identical even though the two missions are flown in vastly different orbits. Additionally, the requirement for a three year mission utilizing a single silver-cadmium battery had never been imposed before. A power subsystem configuration which met all of the specified requirements was developed. Excellent correlation between preflight and actual flight performance is demonstrated.
Obenschain, A. F.↗
Tall Lunar Tower (TLT) Powering Exploration at the Moon's South Pole
Animation of a conceptual Lunar mission for the Tall Lunar Tower (TLT) robotic in-space assembly system. The landing, deployment, and operation of the tower assembly system is shown. A successful tower assembly and solar power payload is depicted at the lunar south pole. The video is intended to convey how an engineering development unit (EDU) demonstrated at NASA Langley Research Center may look when operated on the Lunar surface. The EDU models are shown in place of flight hardware. The animation was produced by the Advanced Concepts Laboratory with models provided by the TLT team.
Tall Lunar Tower↗
Ares I and Ares V First Stage - Powering Exploration
The National Aeronautics and Space Administration (NASA) Ares Projects Office (APO) is continuing to make progress toward the final design of the first stage propulsion system for the Ares I crew launch vehicle and the Ares V cargo launch vehicle. Ares I and Ares V will provide the space launch capabilities needed to fulfill NASA' s exploration strategy of sending human beings to the Moon, Mars, and beyond. As primary propulsion for the Ares launch vehicles, the Space Shuttle-derived Reusable Solid Rocket Motor (RSRM) is one of the first and most important components to be tested. The first flight of Ares I, called Ares I-X, will occur in April 2009, with booster integration to begin at Kennedy Space Center (KSC) by autumn 2008. The Ares I-X flight will use a combination of flight and simulation hardware to obtain data on controlling the long and narrow crew launch vehicle configuration. The test will use a four-segment RSRM from the Shuttle inventory and a fifth spacer segment to simulate the size and weight of the operational five-segment motor to be used on later flights. The upper stage, Orion crew exploration vehicle, and launch abort system will all be replaced with simulator hardware. Manufacturing work has begun on the spacer segment, as well as the new forward hardware for the booster. Atlas V avionics will be adapted to control Ares I-X' s first stage. That hardware is undergoing hardware-in-the-loop testing in a contractor-provided systems integration laboratory (SIL); a critical design review (CDR) was completed in December 2007. Drogue and main parachute drop tests have also been conducted successfully at Yuma Proving Grounds, allowing the First Stage team to begin fabricating parachutes for Ares I-X. The Ares I-X flight test will be the first flight test for the parachutes. A series of preliminary design technical interchange meetings is being conducted prior to the Ares I-X CDR in January 2007 to ensure readiness for the flight. Much of the First Stage activity in 2007 has focused on a series of preliminary design (PDR) activities associated with each booster subsystem. These events will culminate in a formal preliminary design review in 2008, where subsystems and component specifications will be developed and associated analyses and drawings will be evaluated for technical adequacy. The first stage also has been undergoing a series of trade studies to determine means for upgrading booster performance and reducing operational costs. Performance improvement studies have included changing from polybutadiene acrylonitrile (PBAN) propellant to hydroxyl-terminated polybutadiene (HTPB); replacing aluminum with composite motor casings; and optimizing or upgrading the propellant grain and nozzle structures. Some or all of these changes could result in a block upgrade to the Ares I first stage, after becoming the standard configuration for the Ares V. The cost reduction studies included a change from reusable or recoverable boosters to completely expendable boosters; changing from hydrazine-powered to more environmentally friendly electrohydrostatic actuators (EHAs) on the thrust vector control (TVC) system; and changing the location of the separation plane to reduce the likelihood of recontact upon booster separation. The expendability trade study resulted in a decision to keep the recoverable boosters, as the new hardware costs significantly outweighed the potential operational cost savings due to reduced ground operations. Likewise, due to cost considerations, the team continued using existing hydrazine-powered actuators for the TVC system. The separation plane location for Ares I is still being studied, with results to be announced in 2008. In short, the Ares launch vehicles' first stage is building upon NASA's close familiarity with this Shuttle-derived system, while continuing to seek out improvements for long-term exploration.
Priskos, Alex S.↗
AI-powered exploration of molecular vibrations, phonons, and spectroscopy
The vibrational dynamics of molecules and solids play a critical role in defining material properties, particularly their thermal behaviors. However, theoretical calculations of these dynamics are often computationally intensive, while experimental approaches can be technically complex and resource-demanding. Recent advancements in data-driven artificial intelligence (AI) methodologies have substantially enhanced the efficiency of these studies. This review explores the latest progress in AI-driven methods for investigating atomic vibrations, emphasizing their role in accelerating computations and enabling rapid predictions of lattice dynamics, phonon behaviors, molecular dynamics, and vibrational spectra. Key developments are discussed, including advancements in databases, structural representations, machine-learning interatomic potentials, graph neural networks, and other emerging approaches. Compared to traditional techniques, AI methods exhibit transformative potential, dramatically improving the efficiency and scope of research in materials science. The review concludes by highlighting the promising future of AI-driven innovations in the study of atomic vibrations.
Han, Bowen [Oak Ridge National Laboratory (ORNL), ↗
Exploring Power and Frequency Limits of Printed Circuit Board Dispersive Nonlinear Transmission Lines
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Wright, Travis [Texas Tech University]↗
Research and development of silicon solar cells optimized for space exploration power systems Quarterly report, 1 Apr. - 30 Jun. 1970
Optimized silicon solar cell development for spacecraft with near-sun missions
Iles, P. A.↗
Optimized silicon solar cells for space exploration power systems
A program is described aimed at designing and fabricating improved silicon solar cells for a range of missions extending from 0.1 to 15 astronomical units (Mercury to Jupiter). For missions lying inside Earth radius (Mercury, Venus) the major cell property required was very low series resistance, allowing high curve fill factor to be maintained at the higher intensities. For the Mercury mission, the temperature of the cell had to be kept low. This was achieved by reflecting more of the incident sunlight by use of large area front contacts. For the outer missions (Mars, the Asteroid belts and Jupiter) the formation of a Schottky barrier at the back contact had to be avoided (by use of a P+ layer under the back contact) and the excess leakage current of the PN junction had to be reduced. Optimum grid patterns were also derived and used for these missions.
Iles, P. A.↗
Powering Exploration: The Ares I Crew Launch Vehicle and Ares V Cargo Launch Vehicle
The National Aeronautics and Space Administration (NASA)'s Constellation Program is depending on the Ares Projects to deliver the crew and cargo launch capabilities needed to send human explorers to the Moon and beyond. The Ares Projects continue to make progress toward design, component testing, and early flight testing of the Ares I crew launch vehicle, as well as early design work for Ares V cargo launch vehicle. Ares I and Ares V will form the core space launch capabilities the United States needs to continue its pioneering tradition as a spacefaring nation. This paper will discuss programmatic, design, fabrication, and testing progress toward building these new launch vehicles.
Cook, Stephen A.↗
Ares I First Stage: Powering Exploration
he mission of the National Aeronautics and Space Administration (NASA) is not simply to maintain its current position with the International Space Station and other space exploration endeavors, but to build a permanent outpost on the Moon and then travel on to explore ever more distant terrains. The Constellation Program will oversee the development of the crew capsule, launch vehicles, and other systems needed to achieve this mission. From this initiative will come two new launch vehicles: the Ares I and Ares V. The Ares I will be a human-rated vehicle, which will be used for crew transport; the Ares V, a cargo transport vehicle, will be the largest launch vehicle ever built. The Ares Projects team at Marshall Space Flight Center (MSFC) in Huntsville, Alabama is assigned with developing these two new vehicles. The Ares I vehicle will have an in-line, two-stage rocket configuration. The first stage will provide the thrust or propulsion component for the Ares rocket systems through the first two minutes of the mission. The First Stage Team is tasked with developing the propulsion system necessary to liftoff from the Earth and loft the entire Ares vehicle stack toward low-Earth orbit. Building on the legacy of the Space Shuttle and other NASA space exploration initiatives, the propulsion for the Ares I First Stage will be a Shuttle-derived reusable solid rocket motor. Progress to date by the First Stage Team has been robust and on schedule. This presentation provides an overview and update on the design and development of the Ares I First Stage Propulsion system.
Tiller, Bruce K.↗
Ares I First Stage: Powering Exploration
I. Ares First Stage design is on schedule. a) Avionics; b) Major Structures; c) Motor; and d) Deceleration System II. Ares I-X hardware is complete and assembly at KSC is underway. Launch scheduled for October 31. III. Recovery system testing is on schedule a) Drogue; b) Main chute; and c) Cluster. DM-1 static firing is scheduled for August 25, 2009
Tiller, Bruce K.↗
Exploring Power and Frequency Limits of Printed Circuit Board Dispersive Nonlinear Transmission Lines
Explore the source record for details and available documents.
Black, Nathan [Texas Tech University]↗