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At least 145 records · Page 8

NASA's UAS Integration into the NAS: A Report on the Human Systems Integration Phase 1 Simulation Activities

In 2011 the National Aeronautics and Space Administration (NASA) began a five-year Project to address the technical barriers related to routine access of Unmanned Aerial Systems (UAS) in the National Airspace System (NAS). Planned in two phases, the goal of the first phase was to lay the foundations for the Project by identifying those barriers and key issues to be addressed to achieve integration. Phase 1 activities were completed two years into the five-year Project. The purpose of this paper is to review activities within the Human Systems Integration (HSI) subproject in Phase 1 toward its two objectives: 1) develop GCS guidelines for routine UAS access to the NAS, and 2) develop a prototype display suite within an existing Ground Control Station (GCS). The first objective directly addresses a critical barrier for UAS integration into the NAS - a lack of GCS design standards or requirements. First, the paper describes the initial development of a prototype GCS display suite and supporting simulation software capabilities. Then, three simulation experiments utilizing this simulation architecture are summarized. The first experiment sought to determine a baseline performance of UAS pilots operating in civil airspace under current instrument flight rules for manned aircraft. The second experiment examined the effect of currently employed UAS contingency procedures on Air Traffic Control (ATC) participants. The third experiment compared three GCS command and control interfaces on UAS pilot response times in compliance with ATC clearances. The authors discuss how the results of these and future simulation and flight-testing activities contribute to the development of GCS guidelines to support the safe integration of UAS into the NAS. Finally, the planned activities for Phase 2, including an integrated human-in-the-loop simulation and two flight tests are briefly described.

National Airspace System↗

Experimental Evaluation of Refrigerant Leak Characteristics for Different HVAC&R Equipment Types–Phase 2

The US Department of Energy (DOE) Building Technology Office (BTO) and the Air-conditioning, Heating & Refrigeration Technology Institute (AHRTI) collaborated to sponsor an experimental study of refrigerant leak characteristics at Oak Ridge National Laboratory (ORNL); AHRTI project 9012. The project has been conducted in two phases with objectives to conduct refrigerant leak tests on several heating, ventilating, air-conditioning and refrigeration (HVAC&R) systems under operating conditions representative of actual applications to document the pressure decay rate and the mass flow rate of leaked refrigerant as a function of time. Phase 1 of the project ran from late 2017 to late 2018 with refrigerant leaks imposed on five systems and the collection of data to meet the project objectives. Systems chosen covered three air-conditioning (AC) applications (packaged terminal AC or PTAC, 3-ton residential split system AC, and 5-ton packaged rooftop AC) and two refrigeration applications (split system unit cooler, and standalone display case). AHRTI members donated the test systems used for the project. The systems were tested at two different leak rates (catastrophic high rate simulating full line break and a lower flow rate), two leak locations (high-pressure side and low-pressure side), and two operating conditions (compressor ON or OFF). Phase 1 results were summarized in a project report by Baxter, et al. (2019)1. The leak rates imposed in Phase 1 led to much more rapid charge releases than the more typical much slower rates seen in practice that would take days, weeks, or months to empty a system of its entire charge. For Phase 2, the project sponsors asked that the “higher” leak rate target a total charge release time of about 4 min. This was intended to represent a “reasonable” worst case release scenario to match the refrigerant leak rate assumption used in the International Electrotechnical Commission (IEC) standard IEC 60335-2-40 (2016 version [IEC 2016]. A charge release time of about 20–40 min (leak release rate 5 to 10 times lower than higher rate) was targeted for the “lower” leak rate. This report provides a summary of the Phase 2 effort. Two additional HVAC systems were selected for testing in this phase. First was a multi-split air-conditioning (MS-AC) system with one outdoor section and two indoor units and a nameplate refrigerant charge of 1.75 kg (3.86 lb.) of R-410A. The MS-AC was tested in cooling only or AC operation. Second was a split system heat pump coupled to two different representative supply duct systems (HP-duct) and a nameplate charge of 3.83 kg (8.44 lb.) of R-410A. This system was tested in both space heating and AC modes. As in Phase 1 of the project, all tests were conducted using R-410A.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Spitzer Pre Launch Mission Operations System - The Road to Launch

Spitzer Space Telescope was launched on 25 August 2003 into an Earth-trailing solar orbit to acquire infrared observations from space. Development of the Mission Operations System (MOS) portion prior to launch was very different from planetary missions from the stand point that the MOS teams and Ground Data System had to be ready to support all aspects of the mission at launch (i.e., no cruise period for finalizing the implementation). For Spitzer, all mission-critical events post launch happen in hours or days rather than months or years, as is traditional with deep space missions. At the end of 2000 the Project was dealt a major blow when the Mission Operations System (MOS) had an unsuccessful Critical Design Review (CDR). The project made major changes at the beginning of 2001 in an effort to get the MOS (and Project) back on track. The result for the Spitzer Space Telescope was a successful launch of the observatory followed by an extremely successful In Orbit Checkout (IOC) and operations phase. This paper describes how the project was able to recover the MOS to a successful Delta (CDR) by mid 2001, and what changes in philosophies, experiences, and lessons learned followed. It describes how projects must invest early or else invest heavily later in the development phase to achieve a successful operations phase.

observatory↗

Tethers in space: Birth and growth of a new avenue to space utilization

The evolution of the ideas of tether applications in space are traced from its origin in the last century past a dormant period of sixty-five years to the mid-seventies. At that time as a consequence of major revival efforts, NASA entered into serious investigations of the theoretical and practical feasibility of a large number of tethered concepts in space. These efforts culminated in the establishment of the Tethered Satellite System Project now at NASA in the advanced development phase. Extensive planning efforts are described, first, through a Tether Applications in Space Workshop which generated additional concepts and provided overall assessments and recommendations to NASA, and then through a NASA inter-center Tether Applications in Space Task Group which generated a four year program plan in the areas of further studies, technology, work and science and applications of tethers in space. An outlook into the future of tether applications that approaches some of the goals of the early visionaries is offered.

Vontiesenhausen, G.↗

Materials Data on Ta4AlC3 by Materials Project

Ta4AlC3 is MAX Phase structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Ta sites. In the first Ta site, Ta is bonded in a 3-coordinate geometry to three equivalent Al and three equivalent C atoms. All Ta–Al bond lengths are 2.89 Å. All Ta–C bond lengths are 2.17 Å. In the second Ta site, Ta is bonded to six C atoms to form a mixture of edge and corner-sharing TaC6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are three shorter (2.22 Å) and three longer (2.25 Å) Ta–C bond lengths. Al is bonded in a 12-coordinate geometry to six equivalent Ta atoms. There are two inequivalent C sites. In the first C site, C is bonded to six Ta atoms to form a mixture of edge and corner-sharing CTa6 octahedra. The corner-sharing octahedral tilt angles are 1°. In the second C site, C is bonded to six equivalent Ta atoms to form a mixture of edge and corner-sharing CTa6 octahedra. The corner-sharing octahedral tilt angles are 1°.

36 MATERIALS SCIENCE↗

Materials Data on CsYb3Se4 by Materials Project

CsYb3Se4 is MAX Phase structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Cs1+ is bonded in a 6-coordinate geometry to six equivalent Se2- atoms. All Cs–Se bond lengths are 3.63 Å. There are two inequivalent Yb+2.33+ sites. In the first Yb+2.33+ site, Yb+2.33+ is bonded to six Se2- atoms to form a mixture of corner and edge-sharing YbSe6 octahedra. The corner-sharing octahedral tilt angles are 1°. There are three shorter (2.92 Å) and three longer (3.00 Å) Yb–Se bond lengths. In the second Yb+2.33+ site, Yb+2.33+ is bonded to six equivalent Se2- atoms to form a mixture of corner and edge-sharing YbSe6 octahedra. The corner-sharing octahedral tilt angles are 1°. All Yb–Se bond lengths are 2.96 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three equivalent Cs1+ and three equivalent Yb+2.33+ atoms to form a mixture of distorted corner, edge, and face-sharing SeCs3Yb3 octahedra. The corner-sharing octahedra tilt angles range from 2–39°. In the second Se2- site, Se2- is bonded to six Yb+2.33+ atoms to form a mixture of corner and edge-sharing SeYb6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°.

36 MATERIALS SCIENCE↗

Materials Data on Ti4AlN3 by Materials Project

Ti4AlN3 is MAX Phase structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Ti sites. In the first Ti site, Ti is bonded to six N atoms to form a mixture of edge and corner-sharing TiN6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are three shorter (2.11 Å) and three longer (2.14 Å) Ti–N bond lengths. In the second Ti site, Ti is bonded in a 3-coordinate geometry to three equivalent Al and three equivalent N atoms. All Ti–Al bond lengths are 2.83 Å. All Ti–N bond lengths are 2.07 Å. Al is bonded to six equivalent Ti and six equivalent Al atoms to form AlTi6Al6 cuboctahedra that share corners with six equivalent AlTi6Al6 cuboctahedra, corners with six equivalent NTi6 octahedra, edges with six equivalent AlTi6Al6 cuboctahedra, edges with six equivalent NTi6 octahedra, and faces with six equivalent AlTi6Al6 cuboctahedra. The corner-sharing octahedral tilt angles are 19°. All Al–Al bond lengths are 2.99 Å. There are two inequivalent N sites. In the first N site, N is bonded to six Ti atoms to form NTi6 octahedra that share corners with three equivalent AlTi6Al6 cuboctahedra, corners with three equivalent NTi6 octahedra, edges with three equivalent AlTi6Al6 cuboctahedra, and edges with nine NTi6 octahedra. The corner-sharing octahedral tilt angles are 1°. In the second N site, N is bonded to six equivalent Ti atoms to form a mixture of edge and corner-sharing NTi6 octahedra. The corner-sharing octahedral tilt angles are 1°.

36 MATERIALS SCIENCE↗

Materials Data on AlV4C3 by Materials Project

V4AlC3 is MAX Phase structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is two-dimensional and consists of two aluminum molecules and two V4C3 sheets oriented in the (0, 0, 1) direction. In each V4C3 sheet, there are two inequivalent V+2.25+ sites. In the first V+2.25+ site, V+2.25+ is bonded in a distorted T-shaped geometry to three equivalent C4- atoms. All V–C bond lengths are 2.00 Å. In the second V+2.25+ site, V+2.25+ is bonded to six C4- atoms to form a mixture of edge and corner-sharing VC6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are three shorter (2.08 Å) and three longer (2.10 Å) V–C bond lengths. There are two inequivalent C4- sites. In the first C4- site, C4- is bonded to six V+2.25+ atoms to form a mixture of edge and corner-sharing CV6 octahedra. The corner-sharing octahedral tilt angles are 1°. In the second C4- site, C4- is bonded to six equivalent V+2.25+ atoms to form a mixture of edge and corner-sharing CV6 octahedra. The corner-sharing octahedral tilt angles are 1°.

36 MATERIALS SCIENCE↗

Materials Data on CaW by Materials Project

CaW is Zintl Phase structured and crystallizes in the tetragonal I4_1/amd space group. The structure is three-dimensional and consists of two CaW frameworks. Ca is bonded to four equivalent W atoms to form distorted corner-sharing CaW4 tetrahedra. All Ca–W bond lengths are 2.99 Å. W is bonded to four equivalent Ca atoms to form distorted corner-sharing WCa4 tetrahedra.

36 MATERIALS SCIENCE↗

Materials Data on Nb4SiC3 by Materials Project

Nb4C3Si is MAX Phase structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is two-dimensional and consists of two silicon molecules and two Nb4C3 sheets oriented in the (0, 0, 1) direction. In each Nb4C3 sheet, there are two inequivalent Nb2+ sites. In the first Nb2+ site, Nb2+ is bonded to six C4- atoms to form a mixture of edge and corner-sharing NbC6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are three shorter (2.25 Å) and three longer (2.28 Å) Nb–C bond lengths. In the second Nb2+ site, Nb2+ is bonded in a distorted T-shaped geometry to three equivalent C4- atoms. All Nb–C bond lengths are 2.20 Å. There are two inequivalent C4- sites. In the first C4- site, C4- is bonded to six equivalent Nb2+ atoms to form a mixture of edge and corner-sharing CNb6 octahedra. The corner-sharing octahedral tilt angles are 1°. In the second C4- site, C4- is bonded to six Nb2+ atoms to form a mixture of edge and corner-sharing CNb6 octahedra. The corner-sharing octahedral tilt angles are 1°.

36 MATERIALS SCIENCE↗

Materials Data on Nb4AlN3 by Materials Project

Nb4AlN3 is MAX Phase structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Nb sites. In the first Nb site, Nb is bonded to six N atoms to form a mixture of corner and edge-sharing NbN6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are three shorter (2.19 Å) and three longer (2.25 Å) Nb–N bond lengths. In the second Nb site, Nb is bonded in a 3-coordinate geometry to three equivalent Al and three equivalent N atoms. All Nb–Al bond lengths are 2.85 Å. All Nb–N bond lengths are 2.20 Å. Al is bonded to six equivalent Nb atoms to form distorted AlNb6 cuboctahedra that share corners with six equivalent NNb6 octahedra, edges with six equivalent AlNb6 cuboctahedra, and edges with six equivalent NNb6 octahedra. The corner-sharing octahedral tilt angles are 16°. There are two inequivalent N sites. In the first N site, N is bonded to six equivalent Nb atoms to form a mixture of corner and edge-sharing NNb6 octahedra. The corner-sharing octahedral tilt angles are 2°. In the second N site, N is bonded to six Nb atoms to form NNb6 octahedra that share corners with three equivalent AlNb6 cuboctahedra, corners with three equivalent NNb6 octahedra, edges with three equivalent AlNb6 cuboctahedra, and edges with nine NNb6 octahedra. The corner-sharing octahedral tilt angles are 2°.

36 MATERIALS SCIENCE↗

Materials Data on Ti4GaC3 by Materials Project

Ti4GaC3 is MAX Phase structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is two-dimensional and consists of two gallium molecules and two Ti4C3 sheets oriented in the (0, 0, 1) direction. In each Ti4C3 sheet, there are two inequivalent Ti+2.25+ sites. In the first Ti+2.25+ site, Ti+2.25+ is bonded in a distorted T-shaped geometry to three equivalent C4- atoms. All Ti–C bond lengths are 2.08 Å. In the second Ti+2.25+ site, Ti+2.25+ is bonded to six C4- atoms to form a mixture of edge and corner-sharing TiC6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are three shorter (2.15 Å) and three longer (2.23 Å) Ti–C bond lengths. There are two inequivalent C4- sites. In the first C4- site, C4- is bonded to six equivalent Ti+2.25+ atoms to form a mixture of edge and corner-sharing CTi6 octahedra. The corner-sharing octahedral tilt angles are 3°. In the second C4- site, C4- is bonded to six Ti+2.25+ atoms to form a mixture of edge and corner-sharing CTi6 octahedra. The corner-sharing octahedral tilt angles are 3°.

36 MATERIALS SCIENCE↗

Materials Data on AlV4N3 by Materials Project

V4AlN3 is MAX Phase structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent V sites. In the first V site, V is bonded to six N atoms to form a mixture of edge and corner-sharing VN6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are three shorter (2.06 Å) and three longer (2.10 Å) V–N bond lengths. In the second V site, V is bonded in a 3-coordinate geometry to three equivalent Al and three equivalent N atoms. All V–Al bond lengths are 2.79 Å. All V–N bond lengths are 1.96 Å. Al is bonded to six equivalent V and six equivalent Al atoms to form AlAl6V6 cuboctahedra that share corners with six equivalent AlAl6V6 cuboctahedra, corners with six equivalent NV6 octahedra, edges with six equivalent AlAl6V6 cuboctahedra, edges with six equivalent NV6 octahedra, and faces with six equivalent AlAl6V6 cuboctahedra. The corner-sharing octahedral tilt angles are 22°. All Al–Al bond lengths are 2.94 Å. There are two inequivalent N sites. In the first N site, N is bonded to six equivalent V atoms to form a mixture of edge and corner-sharing NV6 octahedra. The corner-sharing octahedral tilt angles are 2°. In the second N site, N is bonded to six V atoms to form NV6 octahedra that share corners with three equivalent AlAl6V6 cuboctahedra, corners with three equivalent NV6 octahedra, edges with three equivalent AlAl6V6 cuboctahedra, and edges with nine NV6 octahedra. The corner-sharing octahedral tilt angles are 2°.

36 MATERIALS SCIENCE↗

Materials Data on CsAl by Materials Project

AlCs is Zintl Phase structured and crystallizes in the tetragonal I4_1/amd space group. The structure is three-dimensional and consists of two AlCs frameworks. Cs is bonded to four equivalent Al atoms to form distorted corner-sharing CsAl4 tetrahedra. All Cs–Al bond lengths are 3.62 Å. Al is bonded to four equivalent Cs atoms to form distorted corner-sharing AlCs4 tetrahedra.

36 MATERIALS SCIENCE↗

Materials Data on Ta4AlN3 by Materials Project

Ta4AlN3 is MAX Phase structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Ta sites. In the first Ta site, Ta is bonded to six N atoms to form a mixture of edge and corner-sharing TaN6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are three shorter (2.18 Å) and three longer (2.23 Å) Ta–N bond lengths. In the second Ta site, Ta is bonded in a 3-coordinate geometry to three equivalent Al and three equivalent N atoms. All Ta–Al bond lengths are 2.83 Å. All Ta–N bond lengths are 2.20 Å. Al is bonded in a 12-coordinate geometry to six equivalent Ta atoms. There are two inequivalent N sites. In the first N site, N is bonded to six equivalent Ta atoms to form a mixture of edge and corner-sharing NTa6 octahedra. The corner-sharing octahedral tilt angles are 2°. In the second N site, N is bonded to six Ta atoms to form a mixture of edge and corner-sharing NTa6 octahedra. The corner-sharing octahedral tilt angles are 2°.

36 MATERIALS SCIENCE↗

NASA TEERM Hexavalent Chrome Alternatives Projects

This slide presentation reviews the NASA project to select an alternative to hexavalent chrome in the aerospace industry. Included is a recent historic testing and research that the Agency has performed on (1) the external tank, (2) the shuttle orbiter, (3) the Shuttle Rocket Booster, and (4) the Space Shuttle Main Engine. Other related Technology Evaluation for Environmental Risk Mitigation (TEERM) projects are reviewed. The Phase I process of the project performed testing of alternatives the results are shown in a chart for different coating systems. International collaboration was also reviewed. Phase II involves further testing of pretreatment and primers for 6 and 12 months of exposure to conditions at Launch Pad and the beach. Further test were performed to characterize the life cycle corrosion of the space vehicles. A new task is described as a joint project with the Department of Defense to identify a Hex Chrome Free Coatings for Electronics.

Kessel, Kurt↗

Lunar-Mars Life Support Test Project: Human Factors and Crew Interactions - Phase 2

Phase 2 of the Lunar-Mars Life Support Test Project was conducted in June and July of 1996 at the NASA Johnson Space Center. The primary objective of Phase 2 was to demonstrate and evaluate an integrated physicochemical air revitalization and regenerative water recovery system capable of sustaining a human crew of four for 30 days inside a closed chamber. The crew (3 males and 1 female) was continuously present inside a chamber throughout the 30-day test. The objective of this paper was to describe crew interactions and human factors for the test. Crew preparations for the test included training and familiarization of chamber systems and accommodations, and medical and psychological evaluations. During the test, crew members provided metabolic loads for the life support systems, performed maintenance on chamber systems, and evaluated human factors inside the chamber. Overall, the four crew members found the chamber to be comfortable for the 30-day test. The crew performed well together and this was attributed in part to team dynamics, skill mix (one commander, two system experts, and one logistics lead), and a complementary mix of personalities. Communication with and support by family, friends, and colleagues were identified as important contributors to the high morale of the crew during the test. Lessons learned and recommendations for future testing are presented by the crew in this paper.

Ming, D. W.↗

Trans-Pacific HDR Satellite Communications Experiment Phase-2 Project Plan and Experimental Network

The trans-Pacific high data rate (TP-HDR) satellite communications experiment was proposed at the Japan-U.S. Cooperation in Space (JUCS) Program Workshop held in Hawaii in 1993 and remote high definition video post-production was demonstrated as the first phase trial. ATM-based 45 Mbps trans-Pacific link was established in the first phase, and the following experiments with 155 Mbps was planned as the phase 2. This paper describes the experimental network configuration and project plan of TP-HDR experiment phase 2. Additional information is provided in the original.

Hsu, Eddie↗