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At least 19 records

AMO-EXPRESS-2.5: Crew Autonomy Onboard the International Space Station

NASA is committed to landing American astronauts, including the first woman and the next man, on the Moon by 2024. Currently, the crew cannot take on all functions performed by the ground today, so the future crews will need more automation to reduce the crew workload for future missions. Of significant importance for these missions is the balance between crew autonomy and vehicle automation. The Advanced Exploration Systems (AES) Autonomous Systems and Operations (ASO) Project has been investigating the ability to evaluate crew self-scheduling and activity monitoring for future space missions. The ASO project designed the Autonomous Mission and Operations- EXpedite the PRocessing of Experiments to Space Station Rack-2.5 (AMO-EXPRESS-2.5) payload to evaluate crew self-scheduling and activity monitoring. The AMO-EXPRESS-2.5 builds on the previous AMO-EXPRESS and AMO-EXPRESS-2.0 demonstrations on ISS. The AMO-EXPRESS-2.5 demonstration goals are to prove crew self-scheduling by planning through diagnosing systems expertise, failure detection, procedure recommendation and situational awareness. This paper will describe the development, test and execution results of the AMO-EXPRESS-2.5 demonstration, and will also outline the future planned development and operational efforts to enable autonomy for future deep space manned missions.

Brooke C. Allen↗

Autonomous Medical Officer Support (AMOS) ISS Technology Demonstration: Enabling Earth-Independnt Procedure Guidance

Successful performance of medical procedures during missions beyond low Earth orbit requires novel solutions to replace real-time support from the ground since the communication delay will be longer as the crew travels farther from Earth. The Autonomous Medical Officer Support software Technology Demonstration project (AMOS Tech Demo) on the International Space Station (ISS) evaluates a novel software tool that shifts the emphasis from preflight training and real-time guidance (current ISS paradigm) to in-flight just-in-time (JIT) instruction (a new paradigm for crew medical autonomy). The AMOS platform introduces a novel, streamlined, skill-management archetype for exploration missions; the current AMOS version features comprehensive training and guidance modules for urinary bladder and kidney ultrasound examinations. The primary goal of the AMOS Tech Demo was to confirm telemedical proof-of-concept through initial use of the platform for autonomous imaging activities in an operational setting. Success metrics encompassed 1) successful software deployment, 2) collection of click tracking data, and 3) recording of ultrasound images. Additional aims included collecting crew feedback on a) AMOS implementation, and b) integrated training and procedure support concepts, as well as c) evaluation of AMOS use in an operational setting.

D. Ebert↗

DOE EERE AMO Electrochemistry for Manufacturing (Workshop Report)

The Advanced Manufacturing Office (AMO) aims to improve the efficiency, productivity, environmental impact, and competitiveness of the manufacturing sector. The use of electrochemistry in manufacturing could help AMO achieve these goals with its potential to have significant impact on sustainability, energy and carbon efficiency, and U.S. manufacturing competitiveness. The “Electrochemistry for Manufacturing” workshop series was designed to help AMO understand (1) how electrochemistry can be used within the manufacturing sector to achieve AMO’s goals and (2) the support for technology and workforce development that is needed from AMO to leverage crosscutting efforts that can enable successful outcomes.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Progress towards high efficiency polycrystalline thin-film GaAs AMOS solar cells

Results of Ge film recrystallization using focused laser beams and GaAs film growth on such layers in the making of high efficiency thin-film AMOS solar cells are discussed. Since a conversion efficiency of 14% was obtained for an AMOS cell fabricated on sliced bulk polycrystalline GaAs, high efficiency cells are being developed by chemically vapor-depositing GaAs films on previously recrystallized evaporated Ge films to minimize the grain boundary (GB) effects. Schottky barrier solar cells made on sliced polycrystalline GaAs wafers were studied to investigate the effects of grain boundaries on cell properties and the potential efficiency of GaAs thin-film cells. Ge film recrystallization and the chemical vapor deposition (CVD) of the 2 to 3 micron thick GaAs films are described. AMOS solar cells with 100 Angstrom thick Ag metallization were made on CVD GaAs/recrystallized Ge/W substrates with an energy conversion efficiency of 8%.

Yeh, Y. C. M.↗

Low cost AMOS solar cell development

Recent developments at JPL have demonstrated that high conversion efficiencies are found with GaAs metal semiconductor solar cells when a particular heat treatment processing step is used to introduce an interfacial layer between the metal and the semiconductor. The new cell, called AMOS (Antireflection-Coated Metal-Oxide-Semiconductor), has open circuit voltages of 0.68-0.72 volts and efficiencies of 15% under terrestrial sunlight, as compared to values of 0.45-0.48 volts and 10%, respectively, for similar cells without an interfacial layer. Potentially higher efficiencies are feasible as further improvements are made in optimizing the interfacial layer effect and in increasing the blue response of the cells. A thin film AMOS cell is proposed that uses a thin recrystallized germanium (Ge) layer between a low cost metal substrate and the vapor phase epitaxially (VPE)-grown GaAs.

Stirn, R. J.↗

Radiation effects in GaAs AMOS solar cells

The results of radiation damage produced in AMOS (Antireflecting-Metal-Oxide-Semiconductor) cells with Sb2O3 interfacial oxide layers by 1-MeV electrons are presented. The degradation properties of the cells as a function of irradiation fluences were correlated with the changes in their spectral response, C-V, dark forward, and light I-V characteristics. The active n-type GaAs layers were grown by the OM-CVD technique, using sulfur doping in the range between 3 x 10 to the 15th power and 7 x 10 to the 16th power/cu cm. At a fluence of 10 to the 16th power e/sq cm, the low-doped samples showed I sub sc degradation of 8% and V sub oc degradation of 8%. The high-doped samples showed I sub sc and V sub oc degradation of 32% and 1%, respectively, while the fill factor remained relatively unchanged for both. AMOS cells with water vapor-grown interfacial layers showed no significant change in V sub oc.

Shin, B. K.↗

Optimal design of GaAs-based concentrator space solar cells for 100 AMO, 80 deg C operation

Using a detailed computer code and reasonable values of electrical and optical material parameters from current published literature, parameter optimization studies were performed on three configurations of GaAs-based concentrator solar cells for 100 AMO, 80 C operation. These studies show the possibility of designing GaAs-based solar cells with efficiencies exceeding 22% at 100 AMO 80 C and probable efficiency degradation of less than 15% after a 70% reduction in diffusion length in each cell region.

Goradia, C.↗

Plans for a STRV-2 to AMOS High Data Rate Bi-Directional Optical Communications Link

The Ballistic Missile Defense Organization has developed a high-data rate (155 Mbps - 1 Gbps) optical communications terminal that will be flown on the STRV-2 satellite. The satellite is scheduled for launch in November 1999, and NASA/JPL has been asked to investigate the use of the AMOS facility as a backup ground terminal to a small transportable terminal constructed by Astroterra Corporation of San Diego. The ground terminal built by Astroterra is designed to support a links out to 2000 km, and will be located at the Table Mountain Facility in Wrightwood, California. Subject to BMDO approval, the demonstration from AMOS will begin in early 2000. For the demonstration, the beam-director tracker will serve as the uplink transmitter, and the 1.6-m telescope as the downlink receiver. It will support bi-directional links out to the 3500-km maximum slant range of the satellite's pass.

Wilson, K. E.↗

AMO EXPRESS: A Command and Control Experiment for Crew Autonomy Onboard the International Space Station

NASA is investigating a range of future human spaceflight missions, including both Mars-distance and Near Earth Object (NEO) targets. Of significant importance for these missions is the balance between crew autonomy and vehicle automation. As distance from Earth results in increasing communication delays, future crews need both the capability and authority to independently make decisions. However, small crews cannot take on all functions performed by ground today, and so vehicles must be more automated to reduce the crew workload for such missions. NASA's Advanced Exploration Systems Program funded Autonomous Mission Operations (AMO) project conducted an autonomous command and control experiment on-board the International Space Station that demonstrated single action intelligent procedures for crew command and control. The target problem was to enable crew initialization of a facility class rack with power and thermal interfaces, and involving core and payload command and telemetry processing, without support from ground controllers. This autonomous operations capability is enabling in scenarios such as initialization of a medical facility to respond to a crew medical emergency, and representative of other spacecraft autonomy challenges. The experiment was conducted using the Expedite the Processing of Experiments for Space Station (EXPRESS) rack 7, which was located in the Port 2 location within the U.S Laboratory onboard the International Space Station (ISS). Activation and deactivation of this facility is time consuming and operationally intensive, requiring coordination of three flight control positions, 47 nominal steps, 57 commands, 276 telemetry checks, and coordination of multiple ISS systems (both core and payload). Utilization of Draper Laboratory's Timeliner software, deployed on-board the ISS within the Command and Control (C&C) computers and the Payload computers, allowed development of the automated procedures specific to ISS without having to certify and employ novel software for procedure development and execution. The procedures contained the ground procedure logic and actions as possible to include fault detection and recovery capabilities. The autonomous operations concept includes a reduction of the amount of data a crew operator is required to verify during activation or de-activation, as well as integration of procedure execution status and relevant data in a single integrated display. During execution, the auto-procedures (via Timerliner) provide a step-by-step messaging paradigm and a high-level status upon termination. This messaging and high-level status is the only data generated for operator display. To enhance situational awareness of the operator, the Web-based Procedure Display (WebPD) provides a novel approach to the issues of procedure display and execution tracking. WebPD is a web based application that serves as the user interface for electronic procedure execution. It incorporates several aspects of the HTML5 standard. Procedures are written in a dialect of XML called Procedure Representation Language (PRL). WebPD tracks execution status in the procedure or procedures being displayed. WebPD aggregates and simplifies the auto-sequence execution status information, and formatted to be easily followed and understood by an operator who is not dedicated to actively monitoring the task. WebPD also provides an integrated data and control interface to pause or halt the execution in order to provide a check point of operation and to examine progress before starting the next sequence of activities. For this demonstration, the procedure was initiated and monitored from the ground. As the Timeliner sequences executed, their high-level execution status was written to PLMDM memory. This memory is read and downlinked via Ku-Band at a 1 Hz rate. The data containing the high-level execution status is de-commutated on the ground, and rebroadcast for WebPD consumption. A future demonstration will be performed onboard, with ISS astronauts initiating the operations instead of ground controllers. The AMO EXPRESS experiment demonstrated activation and de-activation of EXPRESS rack 7, providing the capability of future single button activations and deactivations of facility class racks. The experiment achieved numerous technical and operations 'firsts' for the ISS

Stetson, Howard K.↗

Autonomous Medical Officer Support (AMOS) Software Technology Demonstrations on the International Space Station (ISS)

Performance of medical procedures in spaceflight beyond low Earth orbit (LEO) requires novel solutions to replace real-time ground support because as distance from Earth increases, communication latencies increase, hampering remote guidance. The Autonomous Medical Officer Support Software (AMOS) Technology Demonstrations on the International Space Station (ISS) trialed a novel software tool that shifts the emphasis from preflight training and real-time remote guidance (current ISS paradigm) to a new standard of multi-dimensional in-flight just-in-time (JIT) instruction. The AMOS platform is a skill management tool for all mission phases and currently features comprehensive training and guidance modules for urinary bladder and renal ultrasound examinations. Variability in Subject anatomy, Operator experience, and Operator receptiveness to instruction during autonomous exams are persistent but manageable limitations. Here we report the first successful demonstrations of autonomous imaging activities in the operational setting of spaceflight, validating this autonomous guidance proof of concept.

Douglas Ebert↗

Single crystal and polycrystalline GaAs solar cells using AMOS technology

A description is given of current technology for fabricating single AMOS (antireflection-coated metal oxide semiconductor) solar cells, with attention given to thermal, plasma, and anodic oxidation, native oxide stripping, and X-ray photoelectron spectroscopy results. Some preliminary results are presented on the chemistry and electrical characterization of such cells, and the characteristics of cells fabricated on sliced polycrystalline GaAs wafers are examined. Consideration is also given to the recrystallization of evaporated Ge films for use as low-cost substrates for polycrystalline GaAs solar cells.

Stirn, R. J.↗

A 25.5 percent AMO gallium arsenide grating solar cell

Recent calculations have shown that significant open circuit voltage gains are possible with a dot grating junction geometry. The feasibility of applying the dot geometry to the GaAs cell was investigated. This geometry is shown to result in voltages approach 1.120 V and efficiencies well over 25 percent (AMO) if good collection efficiency can be maintained. The latter is shown to be possible if one chooses the proper base resistivity and cell thickness. The above advances in efficiency are shown to be possible in the P-base cell with only minor improvements in existing technology.

Weizer, V. G.↗

Tandem concentrator solar cells with 30 percent (AMO) power conversion efficiency

Very high efficiency concentrator solar panels are envisioned as economical and reliable electrical power subsystems for space based platforms of the future. GaAs concentrator cells with very high efficiencies and good sub-bandgap transmissions can be fabricated on standard wafers. GaSb booster cell development is progressing very well; performance characteristics are still improving dramatically. Consistent GaAs/GaSb stacked cell AMO efficiencies greater than 30 percent are expected.

Avery, J. E.↗

AMO EXPRESS: A Command and Control Experiment for Crew Autonomy Onboard the International Space Station

NASA is investigating a range of future human spaceflight missions, including both Mars-distance and Near Earth Object (NEO) targets. Of significant importance for these missions is the balance between crew autonomy and vehicle automation. As distance from Earth results in increasing communication delays, future crews need both the capability and authority to independently make decisions. However, small crews cannot take on all functions performed by ground today, and so vehicles must be more automated to reduce the crew workload for such missions. NASA's Advanced Exploration Systems Program funded Autonomous Mission Operations (AMO) project conducted an autonomous command and control experiment on-board the International Space Station that demonstrated single action intelligent procedures for crew command and control. The target problem was to enable crew initialization of a facility class rack with power and thermal interfaces, and involving core and payload command and telemetry processing, without support from ground controllers. This autonomous operations capability is enabling in scenarios such as initialization of a medical facility to respond to a crew medical emergency, and representative of other spacecraft autonomy challenges. The experiment was conducted using the Expedite the Processing of Experiments for Space Station (EXPRESS) rack 7, which was located in the Port 2 location within the U.S Laboratory onboard the International Space Station (ISS). Activation and deactivation of this facility is time consuming and operationally intensive, requiring coordination of three flight control positions, 47 nominal steps, 57 commands, 276 telemetry checks, and coordination of multiple ISS systems (both core and payload). Utilization of Draper Laboratory's Timeliner software, deployed on-board the ISS within the Command and Control (C&C) computers and the Payload computers, allowed development of the automated procedures specific to ISS without having to certify and employ novel software for procedure development and execution. The procedures contained the ground procedure logic and actions as possible to include fault detection and recovery capabilities.

Stetson, Howard K.↗

AMO EXPRESS: A Command and Control Experiment for Crew Autonomy

NASA is investigating a range of future human spaceflight missions, including both Mars-distance and Near Earth Object (NEO) targets. Of significant importance for these missions is the balance between crew autonomy and vehicle automation. As distance from Earth results in increasing communication delays, future crews need both the capability and authority to independently make decisions. However, small crews cannot take on all functions performed by ground today, and so vehicles must be more automated to reduce the crew workload for such missions. NASA's Advanced Exploration Systems Program funded Autonomous Mission Operations (AMO) project conducted an autonomous command and control demonstration of intelligent procedures to automatically initialize a rack onboard the International Space Station (ISS) with power and thermal interfaces, and involving core and payload command and telemetry processing, without support from ground controllers. This autonomous operations capability is enabling in scenarios such as a crew medical emergency, and representative of other spacecraft autonomy challenges. The experiment was conducted using the Expedite the Processing of Experiments for Space Station (EXPRESS) rack 7, which was located in the Port 2 location within the U.S Laboratory onboard the International Space Station (ISS). Activation and deactivation of this facility is time consuming and operationally intensive, requiring coordination of three flight control positions, 47 nominal steps, 57 commands, 276 telemetry checks, and coordination of multiple ISS systems (both core and payload). The autonomous operations concept includes a reduction of the amount of data a crew operator is required to verify during activation or de-activation, as well as integration of procedure execution status and relevant data in a single integrated display. During execution, the auto-procedures provide a step-by-step messaging paradigm and a high level status upon termination. This messaging and high level status is the only data generated for operator display. To enhance situational awareness of the operator, the Web-based Procedure Display (WebPD) provides a novel approach to the issues of procedure display and execution tracking. For this demonstration, the procedure was initiated and monitored from the ground. As the Timeliner sequences executed, their high level execution status was transmitted to ground, for WebPD consumption.

Stetson, Howard K.↗

AMO EXPRESS: A Command and Control Experiment for Crew Autonomy Onboard the International Space Station

NASA is investigating a range of future human spaceflight missions, including both Mars-distance and Near Earth Object (NEO) targets. Of significant importance for these missions is the balance between crew autonomy and vehicle automation. As distance from Earth results in increasing communication delays, future crews need both the capability and authority to independently make decisions. However, small crews cannot take on all functions performed by ground today, and so vehicles must be more automated to reduce the crew workload for such missions.NASAs Advanced Exploration Systems Program funded Autonomous Mission Operations (AMO) project conducted an autonomous command and control experiment on-board the International Space Station that demonstrated single action intelligent procedures for crew command and control. The target problem was to enable crew initialization of a facility class rack with power and thermal interfaces, and involving core and payload command and telemetry processing, without support from ground controllers. This autonomous operations capability is enabling in scenarios such as initialization of a medical facility to respond to a crew medical emergency, and representative of other spacecraft autonomy challenges. The experiment was conducted using the Expedite the Processing of Experiments for Space Station (EXPRESS) rack 7, which was located in the Port 2 location within the U.S Laboratory onboard the International Space Station (ISS).

Autonomous Mission Operations↗