A Review of Welding in Space and Related Technologies

Deployment of welding and additive manufacturing (AM) technologies in the space environment has the potential to revolutionize how orbiting platforms are designed, manufactured, and assembled. These technologies offer the option for repair of sustained damage to habitat structures on space missions, as astronauts would be able to manufacture new parts (using welding-derived AM processes suitable for use in the external space environment) and weld cracks. An added benefit is that required repairs can be achieved more economically, as new parts need not be shipped from Earth. With further maturation of in-space welding capabilities, astronauts could operate under given standards and weld damaged structures rather than rely on cargo resupply. This Technical Memorandum (TM) begins by reviewing the available literature relevant to welding in space, focusing on solidification, heat and mass transfer, and fluid flows in microgravity. This survey considers research on the effects of welding in microgravity on a material system. The various in-space welding devices that have been previously designed and tested are examined to determine their capabilities and shortcomings, with a focus on the results of their individual welding experiments. Safety measures are discussed to protect the orbiting International Space Station (ISS) and crew during welding operations. Finally, the state of the art is examined by focusing on current approaches to AM and on-orbit welding that are being developed by several companies in conjunction with NASA

Insertion loss and noise-temperature contribution of high-temperature superconducting bandpass filters centered at 2.3 and 8.45 GHz

Two superconducting Tl-Ca-Cu-Ba-O bandpass filters were fabricated for JPL by Superconductor Technologies Incorporated, Santa Barbara, California. The filters were designed to operate at 2.3 GHz (S-band) with a 0.5-dB bandwidth of 60 MHz and at 8.45 GHz (X-band) with a 0.5-dB bandwidth of 150 MHz. The structure selected for both filters incorporates half-wavelength thin-film resonators in a stripline configuration. The S-band filter uses an edge-coupled interdigital design and the X-band filter uses an end-coupled design. The insertion loss and the noise-temperature contribution were measured at 12 K for both filters

Profit Planning for Irrigated Farming.

4 p

Summary Report on Phase I and Phase II Results From the 3D Printing in Zero-G Technology Demonstration Mission

In-space manufacturing seeks to develop the processes, skill sets, and certification architecture needed to provide a rapid response manufacturing capability on long-duration exploration missions. The first 3D printer on the Space Station was developed by Made in Space, Inc. and completed two rounds of operation on orbit as part of the 3D Printing in Zero-G Technology Demonstration Mission. This Technical Publication provides a comprehensive overview of the technical objections of the mission, the two phases of hardware operation conducted on orbit, and the subsequent detailed analysis of specimens produced. No engineering significant evidence of microgravity effects on material outcomes was noted. This technology demonstration mission represents the first step in developing a suite of manufacturing capabilities to meet future mission needs

ISM In-Space Manufacturing

Develop and enable the technologies, materials, and processes required to provide affordable, sustainable on-demand manufacturing, recycling, and repair during Exploration Missions

NASA's Centennial Challenge for 3D-Printed Habitat: Phase II Outcomes and Phase III Competition Overview

The 3D-Printed Habitat Challenge is part of NASA's Centennial Challenges Program. NASA's Centennial Challenges seek to accelerate innovation in aerospace technology development through public competitions. The 3D-Printed Habitat Challenge, launched in 2015, is part of the Centennial Challenges portfolio and focuses on habitat design and development of large-scale additive construction systems capable of fabricating structures from in situ materials and/or mission recyclables. The challenge is a partnership between NASA, Caterpillar (primary sponsor), Bechtel, Brick and Mortar Ventures, and Bradley University. Phase I of the challenge was an architectural concept competition in which participants generated conceptual renderings of habitats on Mars which could be constructed using locally available resources. Phase II asked teams to develop the printing systems and material formulations needed to translate these designs into reality. Work under the phase II competition, which concluded in August 2017 with a head to head competition at Caterpillar's Edward Demonstration Facility in Peoria, Illinois, is discussed, including the key technology development outcomes resulting from this portion of the competition. The phase III competition consists of both virtual and construction subcompetitions. Virtual construction asks teams to render high fidelity architectural models of a habitat and all the accompanying information required for construction of the pressure retaining and load bearing portions of the structure. In construction phase III, teams are asked to scale up their printing systems to produce a 1/3 scale habitat on-site at Caterpillar. The levels of the phase III construction competition (which include printing of a foundation and printing and hydrostatic testing of a habitat element) are discussed. Phase III construction also has an increased focus on autonomy, as these systems are envisioned for robotic precursor missions which would buildup infrastructure prior to the arrival of crew. Results of the phase III competition through July 2017 (which includes virtual construction level 1) are discussed. This Centennial Challenge enables an assessment of the scaleability and efficacy of various processes, material systems, and designs for planetary construction. There are also near-term terrestrial applications, from disaster response to affordable housing and infrastructure refurbishment, for these technologies

Earthquake Resistance of a Rockfill Dam

The paper describes the investigation of the seismic safety of a 131 m high rock fill dam presently under construction across the Rio Chixoy in Guatemala. The dam is located in a region of high seismicity the recently active Motagua fault being only 40 km distant. Due to the possibility of high peak ground accelerations it was considered necessary to conduct a full dynamic analysis, which was carried out in stages following the Seed-Lee-Idriss method, the latter being modified where it was deemed necessary

Relationships among nutrient enrichment, detritus quality and quantity, and large-bodied shredding insect community structure

Anthropogenic nutrient enrichment of forested headwater streams can enhance detrital quality, decrease standing stocks, and alter the community structure of detrivorous insects, reducing nutrient retention and decreasing ecosystem functioning. Our objective was to determine if stoichiometric principles could be used to predict genus-specific shifts in shredding insect abundance and biomass across a dissolved nutrient and detritus food quality/quantity gradient. Detritus, insect, and water samples were collected from 12 Ozark Highland headwater streams. Significant correlations were found between stream nutrients and detrital quality but not quantity. Abundance and biomass responses of four out of five tested genera were accurately predicted by consumerresource stoichiometric theory. Low carbon:phosphorus (C:P) shredders responded positively to increased total phosphorus and/or food quality, and high C:P shredders exhibited neutral or negative responses to these variables. Genus-specific declines were correlated with decreased overall biomass in shredder assemblages, potentially causing disruptions in nutrient flows to higher level consumers with nutrient enrichment. This work provides further evidence that elevated nutrients may negatively impact shredding insect communities by altering the stoichiometry of detritus–detritivore interactions. A better understanding of stoichiometric mechanisms altering macroinvertebrate populations is needed to help inform water quality criteria for the management of headwater streams