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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 19 records

Radiation Testing of PICA at the Solar Power Tower

Sandia National Laboratory's Solar Power Tower was used to irradiate specimens of Phenolic Impregnated Carbon Ablator (PICA), in order to evaluate whether this thermal protection system material responded differently to potential shock layer radiative heating than to convective heating. Tests were run at 50, 100 and 150 Watts per square centimeter levels of concentrated solar radiation. Experimental results are presented both from spectral measurements on 1- 10 mm thick specimens of PICA, as well as from in-depth temperature measurements on instrumented thicker test specimens. Both spectral measurements and measured in-depth temperature profiles showed that, although it is a porous, low-density material, PICA does not exhibit problematic transparency to the tested high levels of NIR radiation, for all pragmatic cm-to-inch scale thicknesses. PICA acted as a surface absorber to efficiently absorb the incident visible and near infrared incident radiation in the top 2 millimeter layer in the Solar Power Tower tests up to 150 Watts per square centimeter.

White, Susan M.↗

Radiation Testing of PICA at the Solar Power Tower

Sandia National Laboratory's Solar Power Tower was used to irradiate specimens of Phenolic Impregnated Carbon Ablator (PICA), in order to evaluate whether this thermal protection system material responded differently to potential shock layer radiative heating than to convective heating. Tests were run at 50, 100 and 150 Watts per square centimeter levels of concentrated solar radiation. Experimental results are presented both from spectral measurements on 1- 10 mm thick specimens of PICA, as well as from in-depth temperature measurements on instrumented thicker test specimens. Both spectral measurements and measured in-depth temperature profiles showed that, although it is a porous, low-density material, PICA does not exhibit problematic transparency to the tested high levels of NIR radiation, for all pragmatic cm-to-inch scale thicknesses. PICA acted as a surface absorber to efficiently absorb the incident visible and near infrared incident radiation in the top 2 millimeter layer in the Solar Power Tower tests up to 150 Watts per square centimeter.

White, Susan↗

Advanced Electric Propulsion for Space Solar Power Satellites

The sun tower concept of collecting solar energy in space and beaming it down for commercial use will require very affordable in-space as well as earth-to-orbit transportation. Advanced electric propulsion using a 200 kW power and propulsion system added to the sun tower nodes can provide a factor of two reduction in the required number of launch vehicles when compared to in-space cryogenic chemical systems. In addition, the total time required to launch and deliver the complete sun tower system is of the same order of magnitude using high power electric propulsion or cryogenic chemical propulsion: around one year. Advanced electric propulsion can also be used to minimize the stationkeeping propulsion system mass for this unique space platform. 50 to 100 kW class Hall, ion, magnetoplasmadynamic, and pulsed inductive thrusters are compared. High power Hall thruster technology provides the best mix of launches saved and shortest ground to Geosynchronous Earth Orbital Environment (GEO) delivery time of all the systems, including chemical. More detailed studies comparing launch vehicle costs, transfer operations costs, and propulsion system costs and complexities must be made to down-select a technology. The concept of adding electric propulsion to the sun tower nodes was compared to a concept using re-useable electric propulsion tugs for Low Earth Orbital Environment (LEO) to GEO transfer. While the tug concept would reduce the total number of required propulsion systems, more launchers and notably longer LEO to GEO and complete sun tower ground to GEO times would be required. The tugs would also need more complex, longer life propulsion systems and the ability to dock with sun tower nodes.

Oleson, Steve↗

Transformers for Lunar Extreme Environments: Ensuring Long-Term Operations in Regions of Darkness and Low Temperatures: II - Phase

This report shows how solar power could enable robotic operations in permanently shaded regions at lunar poles, to extract water ice and further produce liquid hydrogen and oxygen (LH2/LO2) propellant. The power needs are derived from an Architecture for Human Exploration of Mars based entirely on lunar propellant. The extraction of 10 metric tons of water per day (at 10% water in regolith) requires approx. 0.6 MW thermal power. Additional approx. 2 MW electric power are required to produce 7.5 metric tons of LH2/LO2 propellant per day, as needed by the architecture. To provide power to processing equipment inside Shackleton Crater, optimal locations are determined on the crater rim, from which several reflecting TransFormers (TFs) would redirect sunlight, achieving a combined period of illumination of approx. 99% of the year. A single 40-m diameter reflector could provide up to 1 MW solar power. Inflatable rigidizable tower support structures raise reflectors above ground for better solar exposure. There are trade-offs: e.g., two reflectors at ground level would provide the same combined total illumination as a single tower approx. 100-m tall. Such a TF based on a 100-m tower made with inflatable 2-m beams and 40-m diameter reflectors would be of similar dimensions as an MSL-class rover (approx. 1000 kg, 10 m(exp 3)). A TF-prospector rover combo could be designed and deployed in a Discovery-class mission searching for water. The TransFormers would be nodes of a Lunar Utilities Infrastructure that provides solar power year-round in the proximity of the pole, as well as local data transmission andintermittent direct to earth communications. This infrastructure would be instrumental infacilitating the development of a lunar economy.

fuel↗

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↗

Beamed Energy and Communications Optical Node (BEACON) Demonstrator

Due to long shadow periods (2 weeks or greater) on the south pole, concepts to raise solar arrays to a sufficient height at specific locations have shown the capability to provide power to surface users for much longer periods. Such a tower can also provide a 3rd Generation Partnership Project (3GPP) service for users up to 10 km away, dependent on terrain. An option to deliver power, albeit with low efficiency, using a laser beam coupled with the tower height could provide mobile and fixed users power during darkness, reducing their battery requirements. A demonstration of these technologies in the lunar environment is crucial to support future Artemis campaigns as well as potential emerging lunar infrastructures. A demonstrator design of a 15 m deployed boomon the south pole has been shown to enable both the gathering of kilowatts of power and the provision of 3GPP relay and backhaul given an appropriate lunar location. Using a laser to send power to a photovoltaic receiver has been proposed to transmit electrical power on the moon, particularly for applications such as powering a rover in near-polar permanently shadowed regions (PSR) where solar power is not available. In this work, the Compass team performed a conceptual engineering design study of a near-term laser surface-to-surface power beaming and relay station using a tower to simultaneously carry the power source (Vertical Solar Array Technologies (VSAT)[1]), the 3GPP relay antenna, and the laser telescope.

Lunar Relay↗

Beamed Energy and Communications Optical Node (BEACON) Demonstrator

Due to long shadow periods (2 weeks or greater) on the south pole, concepts to raise solar arrays to a sufficient height at specific locations have shown the capability to provide power to surface users for much longer periods. Such a tower can also provide a 3rd Generation Partnership Project (3GPP) service for users up to 10 km away, dependent on terrain. An option to deliver power, albeit with low efficiency, using a laser beam coupled with the tower height could provide mobile and fixed users power during darkness, reducing their battery requirements. A demonstration of these technologies in the lunar environment is crucial to support future Artemis campaigns as well as potential emerging lunar infrastructures. A demonstrator design of a 15 m deployed boomon the south pole has been shown to enable both the gathering of kilowatts of power and the provision of 3GPP relay and backhaul given an appropriate lunar location. Using a laser to send power to a photovoltaic receiver has been proposed to transmit electrical power on the moon, particularly for applications such as powering a rover in near-polar permanently shadowed regions (PSR) where solar power is not available. In this work, the Compass team performed a conceptual engineering design study of a near-term laser surface-to-surface power beaming and relay station using a tower to simultaneously carry the power source (Vertical Solar Array Technologies (VSAT)[1]), the 3GPP relay antenna, and the laser telescope.

Deployable solar array tower laser beamed power 3G↗

Sizing and Design Tool for Tall Lunar Tower

Tall lunar towers enable direct collection of solar energy using solar panels that can generate power exceeding 50kW. Tall lunar towers also support solar reflectors and concentrators for solar farms, which enable various mission architectures on the lunar surface. The Tall Lunar Tower project at NASA Langley Research Center is focused on the design, modeling, fabrication, and testing of an assembled tall lunar tower engineering development unit. This paper presents the development of a sizing and design tool for the tall lunar tower. The predicted frequency and buckling responses of the tall lunar tower from the tool are compared with the results obtained from finite element analysis.

Solar Tower↗

Sizing and Design Tool for Tall Lunar Tower

Tall lunar towers enable direct collection of solar energy using solar panels that can generate power exceeding 50kW. Tall lunar towers also support solar reflectors and concentrators for solar farms, which enable various mission architectures on the lunar surface. The Tall Lunar Tower project at NASA Langley Research Center is focused on the design, modeling, fabrication, and testing of an assembled tall lunar tower engineering development unit. This paper presents the development of a sizing and design tool for the tall lunar tower. The predicted frequency and buckling responses of the tall lunar tower from the tool are compared with the results obtained from finite element analysis.

Solar Tower↗

Automated Reconfigurable Mission Adaptive Digital Assembly Systems (ARMADAS): Robotically Assembled Sustainable Lunar Infrastructure

Introduction: The Automated Reconfigurable Mission Adaptive Digital Assembly Systems (ARMADAS) project at NASA Ames Research Center is developing autonomous infrastructure, instrumentation, and spacecraft assembly and manufacturing capabilities for next generation exploration and science missions, with a goal to change the cost scaling of these missions relative to mission size and duration. Using a building-block approach with a 'kit of parts' composed of ultra-light, high-performance mechanical metamaterials, simplified robots leverage the period environment to achieve high levels of autonomy and reliability for in-space and surface assembly of large-scale apertures, solar-arrays, towers, habitats, and other infrastructure. Robots and structure break down into a compact form factor for launch. By leveraging economies of scale and achieving high-packing ratios, ARMADAS technology can revolutionize possible space missions by breaking the tyranny of the launch shroud, decreasing development times, decreasing mission costs for transformative science capability, and providing a scalable and versatile space infrastructure strategy. Capabilities: To date, the ARMADAS project has demonstrated autonomous assembly of large numbers of structural modules into a meters-scale structure in an earth gravity environment. The mechanical performance is on par with conventional space structures, at a fraction of the cost. By using highly repeatable manufacturing processes (injection molding carbon fiber reinforced space-rated polymers), the structures are both cost effective and highly precise. The ARAMADAS system carefully designs parts for high-precision assembly–the simple and cost-effective robots build structures much larger and more precise than themselves. While maintaining structural efficiency, the ARMADAS system encompasses many functional module types, including for solar power, comm/power routing, etc., that will enable entire infrastructure systems to be engineered and autonomously assembled with modular parts. With well-defined interfaces, custom instrumentation modules can easily be added to fit many mission objectives. Lunar Infrastructure Vision: At the LSIC spring meeting, ARMADAS will present a vision for a general-purpose lunar construction kit capable of meeting a wide variety of lunar surface infrastructure needs (Figure 1). Investing in an ecosystem of reconfigurable, discretely repairable parts and robots enables systems than can expand their capability, reconfigure to meet emergency or unforeseen needs, self-repair and reduce spare-part needs. With a small set of parts (module types), a wide variety of infrastructure needs can be met. Footing modules will allow infrastructure construction at locations with no surface preparation. Footer, primary structure, and rail modules can create reconfigurable rail systems. These rail systems can be used to reduce cost-of-transport between frequently accessed sites, provide dust mitigation, and convey power and communications. High-performance structure modules combined with power-routing and solar modules can create tall towers for power and communication. Concepts for habitats and garages encompass a structure to support regolith cover for a pre-integrated module to an entirely ARMADAS system-based structure. This system can be leveraged by many in-situ resource utilization (ISRU) technologies to simplify processes and augment capabilities.

C. E. Gregg↗

Tall Lunar Towers: Systems Analysis of a Lunar-Surface-Assembled Power, Communication, and Navigation Infrastructure

The National Aeronautics and Space Administration (NASA) intends to develop and maintain a human-lunar presence, requiring infrastructure on the Lunar South Pole. To keep pace with the continued growth in cislunar activity, there is national interest in developing a global lunar infrastructure network for power and Communication, Position, Navigation, and Timing (CPNT). Demonstrating autonomous construction capabilities is an infrastructure-enabling objective. This study explores several architecture trade studies to assess the feasibility of alternative lunar infrastructure concepts. 50 m towers, for instance, enable solar power generation up to 99% of a lunar year in addition to acting as wide-range communication and navigation surface relays. The infrastructure network considered in this study consisted of tower platforms, utilities hosted on the towers, and both crewed and robotic end users. High-level trades were analyzed, such as tower height, location, and distributed vs centralized power grids. Results indicated that even with minimal permanent surface assets (darkness survival power loads on the order of 5 kW or greater), at any of the five locations considered, taller towers resulted in lower infrastructure mass than shorter towers; up to 24% system mass savings were realized by reducing battery mass. Simultaneously, taller towers increased the range of communication coverage; a 50 m tower on the Connecting Ridge had 5 kg more structure and 76% more line-of-sight coverage to a two-meter-tall end user than a 10 m tower with the same location and user height. Leveraging a grid of tall towers for nominal power and communication would not only save up to 2,800 kg in battery mass but would be more maintainable and allow users to take advantage of generational upgrades.

lunar infrastructure↗

Tall Lunar Tower: An Autonomously Assembled Tower for Early Lunar Infrastructure

The Tall Lunar Tower (TLT) In-Space Assembly (ISA) team aims to design, model, fabricate, autonomously assemble, and characterize a TLT engineering development unit (EDU). The autonomous assembly of a tower also demonstrates a cross-cutting technology that can be applied to other lunar structures, such as blast shields, radiation shelters, and safe havens.

In-Space Assembly↗

Solar thermal electric power plants - Their performance characteristics and total social costs

The central receiver (power tower) concept as a thermal conversion approach to the conversion of solar energy into electricity is compared to other solar power plant designs which feature distributed solar collection and use other types of solar collector configurations. A variety of solar thermal storage concepts are discussed and their impacts on system performance are assessed. Although a good deal of quantification is possible in a comparative study, the subjective judgments carry enormous weight in a socio-economic decision, the ultimate choice of central power plant being more a social than an economic or technical decision. Major elements of the total social cost of each type of central plant are identified as utility economic costs, R&D funds, health costs, and other relevant social impacts.

Caputo, R. S.↗

Sizing, Buckling, and Thermal-Structural Analysis of Tall Lunar Tower

Tall lunar towers enable direct collection of solar energy using solar panels that can generate power exceeding 100-kW above shadowed regions on the surface. Tall lunar towers also support solar reflectors and concentrators for solar farms, which enable various mission architectures on the lunar surface. The Tall Lunar Tower (TLT) project at NASA Langley Research Center is focused on the design, modeling, fabrication, and testing of an assembled TLT Engineering Development Unit (EDU). In this paper, the design and analysis plan of a TLT is presented and predicted buckling and thermal-structural response of the TLT EDU on the lunar surface are investigated.

Kyongchan Song↗

Sizing, Buckling, and Thermal-Structural Analysis of Tall Lunar Tower

Tall lunar towers enable direct collection of solar energy using solar panels that can generate power exceeding 100-kW above shadowed regions on the surface. Tall lunar towers also support solar reflectors and concentrators for solar farms, which enable various mission architectures on the lunar surface. The Tall Lunar Tower (TLT) project at NASA Langley Research Center is focused on the design, modeling, fabrication, and testing of an assembled TLT Engineering Development Unit (EDU). In this paper, the design and analysis plan of a TLT is presented and predicted buckling and thermal-structural response of the TLT EDU on the lunar surface are investigated.

Kyongchan Song↗

Hardware Systems and EDU Demonstration of the Tall Lunar Tower Project

The Tall Lunar Tower (TLT) project developed a robotic tower assembly system (RTAS) and TLT Truss engineering development units (EDUs) to perform a ground demonstration of supervised semi-autonomous robotic assembly of a truss-based tall tower. Truss structures provide exceptional strength-to-weight ratios for payload capabilities supporting large masses. On the lunar surface, tall towers are a critical structural system that will enable significant solar power generation by supporting vertical solar arrays and beyond-the-horizon communications at the lunar south pole, supporting the Artemis mission architecture, as well as a lunar economy. Tall towers, greater than 30-meters-tall, provide the elevation needed for more consistent solar power generation due to low inclination sunlight and deep shadowing from surface features on the lunar surface at the poles. The robotic structural assembly technologies developed for truss-based tall towers will also enable other large-scale functional lunar structures to be built, including launch plume deflectors, lunar safe havens for astronauts and assets, surface transportation for cargo, and other critical infrastructure. Robotic assembly of truss structures for lunar surface infrastructure is near-term enabling for future Artemis mission campaign and Moon to Mars Objectives needs for power and communication. The project team designed, fabricated, tested, and demonstrated the RTAS EDU by assembling a TLT Truss EDU in a laboratory environment. The hardware systems and the supervised semi-autonomous assembly process for a TLT assembled EDU design, along with descriptions of a hardware demonstration are presented.

In-space Assembly↗

Hardware Systems and EDU Demonstration of the Tall Lunar Tower Project

The Tall Lunar Tower (TLT) project developed a robotic tower assembly system (RTAS) and TLT Truss engineering development units (EDUs) to perform a ground demonstration of supervised semi-autonomous robotic assembly of a truss-based tall tower. Truss structures provide exceptional strength-to-weight ratios for payload capabilities supporting large masses. On the lunar surface, tall towers are a critical structural system that will enable significant solar power generation by supporting vertical solar arrays and beyond-the-horizon communications at the lunar south pole, supporting the Artemis mission architecture, as well as a lunar economy. Tall towers, greater than 30-meters-tall, provide the elevation needed for more consistent solar power generation due to low inclination sunlight and deep shadowing from surface features on the lunar surface at the poles. The robotic structural assembly technologies developed for truss-based tall towers will also enable other large-scale functional lunar structures to be built, including launch plume deflectors, lunar safe havens for astronauts and assets, surface transportation for cargo, and other critical infrastructure. Robotic assembly of truss structures for lunar surface infrastructure is near-term enabling for future Artemis mission campaign and Moon to Mars Objectives needs for power and communication. The project team designed, fabricated, tested, and demonstrated the RTAS EDU by assembling a TLT Truss EDU in a laboratory environment. The hardware systems and the supervised semi-autonomous assembly process for a TLT assembled EDU design, along with descriptions of a hardware demonstration are presented.

Lunar Infrastructure↗

Towers: Critical Initial Infrastructure for the Moon, Such as a Power Module Support

Towers are an efficient structure commonly used to elevate systems against a gravity field, such as above the surface of a planet or the Moon. Towers can be used to elevate antennas, transmitters and sensors for communication, navigation, and observation infrastructure in support of surface operations. Near the Lunar poles, elevation of rotating solar panels enables nearly continuous panel illumination for solar power production despite the Sun remaining near the horizon year-round. Further, once technology is developed for tower assembly, this same technology can be extended to the assembly of a variety of structures including rocket blast containment shields, bridges, shelters, and habitats from either Earth-sourced or Lunar-sourced structural members. Environmental factors on the Lunar surface are vastly different than those found on Earth and have significant impact on the design of towers. Towers designed for the Lunar surface have no heritage nor Earth analog. The designs discussed herein are therefore breaking new ground creating a fundamentally new class of structures outside of current experience and intuition. The purpose of this paper is to: a) describe the unique environmental factors affecting tower design on the Lunar surface compared to Earth-based systems, b) evaluate two structural forms for the tower; telescoping tubes and an assembled truss, as well as c)provide recommendations on when each structural form is most suitable. A major contribution presented in the current paper is to provide parametric plots and supporting equations of mass and volume versus module power level and blanket height above the Lunar surface for the solar array application, to enable system level studies of optimum power module distribution and size. A secondary contribution are plots of the mass and volume of aluminum or structural glass required for assembled truss towers formed from Lunar derived structural members. An objective of achieving 1 MW of total power has been used to enable comparison of structural forms, because the total mass of solar arrays is consistent. It will be shown that for moderate module sizes, up to ~50 kW power modules, based on a telescoping tube tower have advantages, but for power modules from 50 kW to 200 kW an assembled truss tower can be created with half to one third of the tube tower mass. More significantly, when shipped from Earth, an assembled truss tower can be packed into 1/14th to 1/25th of the tube tower volume. Truss designs in the 100 kW to 200 kW range will be shown to be a favorable when assembled from either graphite-epoxy angles shipped from Earth or aluminum angles fabricated from Lunar materials. 50 kW towers are an attractive choice for both a telescoping or assembled tower with the solar arrays elevated 10 m above the Lunar surface, while increased solar array elevation favors 100 kW to 200 kW power modules.

assembly↗