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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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189 records · Page 11

Multimegawatt nuclear electric propulsion - First order system design and performance evaluation

The development of space nuclear power supplies capable of delivering high levels of power (1 to 10 MWe) for long life (5 to 10 years) is being considered. An important potential application of these systems will be to provide power for advanced electric propulsion devices such as ion thrusters or Magneto-Plasma-Dynamic (MPD) thrusters. High-powered Nuclear Electric Propulsion (NEP) concepts based on both ion and MPD thrusters are reviewed. To allow for mission performance evaluation, power supply, power processing, and thruster subsystems are characterized for both ion and MPD propulsion systems designed for operation in the 1 to 10 MWe power range. Several proposed missions which are significantly enhanced by the performance potential of these devices are investigated. Studied missions include near-earth orbit raising, cis-lunar cargo transportation, and planetary exploration. If developed, these 1 to 10 MWe NEP systems may provide a technological base for the development of even larger propulsion systems with power levels of up to hundreds of megawatts. The potential performance and technologies associated with such ultra-high-powered NEP systems is explored.

Sercel, J. C.↗

International Space Exploration Coordination Group Assessment of Technology Gaps for LOx/Methane Propulsion Systems for the Global Exploration Roadmap

As part of the Global Exploration Roadmap (GER), the International Space Exploration Coordination Group (ISECG) formed two technology gap assessment teams to evaluate topic discipline areas that had not been worked at an international level to date. The participating agencies were ASI, CNES, DLR, ESA, JAXA, and NASA. Accordingly, the ISECG Technology Working Group (TWG) recommended two discipline areas based on Critical Technology Needs reflected within the GER Technology Development Map (GTDM): Dust Mitigation and LOX/Methane Propulsion. LOx/Methane propulsion systems are enabling for future human missions Mars by significantly reducing the landed mass of the Mars ascent stage through the use of in-situ propellant production, for improving common fluids for life support, power and propulion thus allowing for diverse redundancy, for eliminating the corrosive and toxic propellants thereby improving surface operations and resusabilty, and for inceasing the performance of propulsion systems. The goals and objectives of the international team are to determine the gaps in technology that must be closed for LOx/Methane to be used in human exploration missions in cis-lunar, lunar, and Mars mission applications. An emphasis is placed on near term lunar lander applications with extensibility to Mars. Each agency provided a status of the substantial amount of Lox/Methane propulsion system development to date and their inputs on the gaps in the technology that are remaining. The gaps, which are now opportunities for collaboration, are then discussed.

Hurlbert, Eric A.↗

Libration Point Navigation Concepts Supporting the Vision for Space Exploration

This work examines the autonomous navigation accuracy achievable for a lunar exploration trajectory from a translunar libration point lunar navigation relay satellite, augmented by signals from the Global Positioning System (GPS). We also provide a brief analysis comparing the libration point relay to lunar orbit relay architectures, and discuss some issues of GPS usage for cis-lunar trajectories.

Carpenter, J. Russell↗

Proceedings of the Next Generation Exploration Conference

The Next Generation Exploration Conference (NGEC) brought together the emerging next generation of space leaders over three intensive days of collaboration and planning. The participants extended the ongoing work of national space agencies to draft a common strategic framework for lunar exploration, to include other destinations in the solar system. NGEC is the first conference to bring together emerging leaders to comment on and contribute to these activities. The majority of the three-day conference looked beyond the moon and focused on the "next destination": Asteroids, Cis-Lunar, Earth 3.0, Mars Science and Exploration, Mars Settlement and Society, and Virtual Worlds and Virtual Exploration.

Schingler, Robbie↗

Chapter 6: Materials for Spacecraft

The general knowledge in this chapter is intended for a broad variety of spacecraft: manned or unmanned, low Earth to geosynchronous orbit, cis-lunar, lunar, planetary, or deep space exploration. Materials for launch vehicles are covered in chapter 7. Materials used in the fabrication of spacecraft hardware should be selected by considering the operational requirements for the particular application and the design engineering properties of the candidate materials. The information provided in this chapter is not intended to replace an in-depth materials study but rather to make the spacecraft designer aware of the challenges for various types of materials and some lessons learned from more than 50 years of spaceflight. This chapter discusses the damaging effects of the space environment on various materials and what has been successfully used in the past or what may be used for a more robust design. The material categories covered are structural, thermal control for on-orbit and re-entry, shielding against radiation and meteoroid/space debris impact, optics, solar arrays, lubricants, seals, and adhesives. Spacecraft components not directly exposed to space must still meet certain requirements, particularly for manned spacecraft where toxicity and flammability are concerns. Requirements such as fracture control and contamination control are examined, with additional suggestions for manufacturability. It is important to remember that the actual hardware must be tested to understand the real, "as-built" performance, as it could vary from the design intent. Early material trades can overestimate benefits and underestimate costs. An example of this was using graphite/epoxy composite in the International Space Station science racks to save weight. By the time the requirements for vibration isolation, Space Shuttle frequencies, and experiment operations were included, the weight savings had evaporated.

Finckenor, Miria M.↗

Space Launch System Trans Lunar Payload Delivery Capability

NASA Marshall Space Flight Center (MSFC) has successfully completed the Critical Design Review (CDR) of the heavy lift Space Launch System (SLS) and is working towards first flight of the vehicle in 2018. SLS will begin flying crewed missions with an Orion to a lunar vicinity every year after the first 2 flights starting in the early 2020's. So as early as 2021 these Orion flights will deliver ancillary payload, termed "Co-Manifested Payload", with a mass of at least 5.5 metric tons and volume up to 280 cubic meters to a cis-lunar destination. Later SLS flights have a goal of delivering as much as 10 metric tons to a cis-lunar destination. This presentation will describe the ground and flight accommodations, interfaces, and resources planned to be made available to Co-Manifested Payload providers as part of the SLS system. An additional intention is to promote a two-way dialogue between vehicle developers and potential payload users in order to most efficiently evolve required SLS capabilities to meet diverse payload requirements.

Jackman, A. L.↗

Building an Economical and Sustainable Lunar Infrastructure to Enable Lunar Science and Space Commerce

A new concept study was initiated to examine the framework needed to gradually develop an economical and sustainable lunar infrastructure using a public private partnerships approach. This approach would establish partnership agreements between NASA and industry teams to develop cis-lunar and surface capabilities for mutual benefit while sharing cost and risk in the development phase and then allowing for transfer of operation of these infrastructure services back to its industry owners in the execution phase. These infrastructure services may include but are not limited to the following: lunar cargo transportation, power stations, energy storage devices, communication relay satellites, local communication towers, and surface mobility operations.

Zuniga, Allison↗

Thermal Design Challenges for In-Flight Exposure to an Electric Propulsion Plasma Plume Environment

The use of electric propulsion to carry out NASA in-space propulsion demands has been increasing. A big part of fulfilling this demand is the Power and Propulsion Element (PPE) for NASA's Lunar Gateway. When built, the PPE will have the largest electric propulsion system to ever fly on a spacecraft, which brings new and difficult challenges. The environment created by the electric propulsion system during on-orbit operation of the thrusters has been shown to be different than those measured during operation in terrestrial vacuum facilities. Understanding the on-orbit environment created by the thrusters and its impacts on the spacecraft is the goal of the Plasma Diagnostic Package (PDP). The PDP is a sensor package, which is being developed by NASA GRC (Glenn Research Center), to fly on the PPE. The PDP will measure different aspects of the thruster plume in order to develop higher fidelity modeling of EP (Electric Power) systems. In order to capture quality measurements of the plume the PDP will need to install sensors in close proximity of it. This poses several unique thermal design challenges. Some of these challenges include: the long duration exposure to plume induced heating, the effects of plume induced erosion and sputter deposition on thermal control surfaces, and the extreme environments of a cis-lunar orbit. This paper looks to define the thermal challenges, explain modeling techniques, and offer design solutions for unique challenges of the PDP mission.

Thermal↗

Selection, Production, and Properties of Regolith Polymer Composites for Lunar Construction

NASA’s Artemis Program seeks to establish a long-term presence on the Moon to enable scientific exploration and expand the cis-lunar economy by utilizing lunar resources through public-private and international partnerships. Over the next decades, a lunar spaceport will need to be established to provide the services and facilities that are necessary to achieve this goal. Robotic construction technologies using in-situ materials must be developed to build up enabling infrastructure such as launch/landing pads, blast protection, power/communications infrastructure, improved roads, improved operational surfaces, and radiation protection shelters. Kennedy Space Center’s Granular Mechanics and Regolith Operations laboratory at Swamp Works has partnered with SpaceFactory and LERA Consulting Structural Engineers to develop the architectural and structural design of an unpressurized lunar shelter. The shelter, called Lunar Infrastructure Asset (LINA), is designed to support 2.3 m of regolith overburden to protect astronauts and surface assets from radiation, meteoroid impact, thermal gradients/cycling, and to withstand moonquakes. LINA’s structural design criteria and the resulting structure design are detailed in separate papers. A Fused Filament Fabrication (FFF) construction process using regolith polymer composites has been developed and is detailed in a separate publication. This paper presents material formulations and selection rationale for each of the composite components that were examined. Formulations include 70:30, 80:20, and 85:15 wt.% mixture ratios of lunar mare simulant Black Point-1 (BP-1): Polylactic Acid (PLA), 80:20 Lunar Highlands Simulant-1 (LHS-1): PLA and an 80:20 BP-1: PLA formulation with a flow enhancer additive. Test samples were printed in simulated lunar dirty thermal vacuum conditions (-190 °C, 10-3 torr). A series of tests were performed on each formulation to characterize the achieved mixture ratio, mechanical strength properties, off-gassing products during vacuum printing, and porosity and density of printed products. The LHS-1: PLA formulation yielded an advantageous combination of properties and was used in a final test that additively constructed a sub-scaled LINA on regolith simulant in dirty vacuum conditions. The materials and construction process presented in this paper are considered to be at Technology Readiness Level (TRL) 5 with additional testing necessary to characterize long term lunar environmental exposure effects.

lunar infrastructure↗