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At least 19 records

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NASA NTRS2017

Development Specification for the FN-323/324, Oxygen Ventilation Loop Fan Assembly

This specification establishes the requirements for design, performance, safety, and manufacture of the FN-323/324, Oxygen Ventilation Loop Fan Assembly as part of the Advanced EMU (AEMU) Portable Life Support System (PLSS). Fan development for the advanced Portable Life Support System (PLSS) began in 2009 with the development of Fan 1.0. This fan was used in PLSS 2.0 for circulation of the ventilation loop gas. Fan 2.0 was delivered in 2015 and will be used in the PLSS 2.5 Live Loads test series. This fan used the same motor as Fan 1.0, but had a larger volute and impeller in hopes of achieving lower speeds. The next iteration of the advanced PLSS fan is the subject of the requirements contained within this document, and will be used with the PLSS 2.5 -302 configuration.

Ralston, Russell↗

NASA NTRS2016

Redesign of the Extravehicular Mobility Unit Airlock Cooling Loop Recovery Assembly

During EVA (Extravehicular Activity) 23 aboard the ISS (International Space Station) on 07/16/2013 an episode of water in the EMU (Extravehicular Mobility Unit) helmet occurred, necessitating a termination of the EVA (Extravehicular Activity) shortly after it began. The root cause of the failure was determined to be ground-processing short-comings of the ALCLR (Airlock Cooling Loop Recovery) Ion Beds which led to various levels of contaminants being introduced into the Ion Beds before they left the ground. The Ion Beds were thereafter used to scrub the failed EMU cooling water loop on-orbit during routine scrubbing operations. The root cause investigation identified several areas for improvement of the ALCLR Assembly which have since been initiated. Enhanced washing techniques for the ALCLR Ion Bed have been developed and implemented. On-orbit cooling water conductivity and pH analysis capability to allow the astronauts to monitor proper operation of the ALCLR Ion Bed during scrubbing operation is being investigation. A simplified means to acquire on-orbit EMU cooling water samples have been designed. Finally, an inherently cleaner organic adsorbent to replace the current lignite-based activated carbon, and a non-separable replacement for the separable mixed ion exchange resin are undergoing evaluation. These efforts are undertaken to enhance the performance and reduce the risk associated with operations to ensure the long-term health of the EMU cooling water circuit.

Steele, John↗

NASA NTRS2016

Redesign of the Extravehicular Mobility Unit Airlock Cooling Loop Recovery Assembly

During EVA (Extravehicular Activity) 23 aboard the ISS (International Space Station) on 07/16/2013 an episode of water in the EMU (Extravehicular Mobility Unit) helmet occurred, necessitating a termination of the EVA (Extravehicular Activity) shortly after it began. The root cause of the failure was determined to be ground-processing short-comings of the ALCLR (Airlock Cooling Loop Recovery) Ion Beds which led to various levels of contaminants being introduced into the Ion Beds before they left the ground. The Ion Beds were thereafter used to scrub the failed EMU cooling water loop on-orbit during routine scrubbing operations. The root cause investigation identified several areas for improvement of the ALCLR Assembly which have since been initiated. Enhanced washing techniques for the ALCLR Ion Bed have been developed and implemented. On-orbit cooling water conductivity and pH analysis capability to allow the astronauts to monitor proper operation of the ALCLR Ion Bed during scrubbing operation is being investigated. A simplified means to acquire on-orbit EMU cooling water samples has been designed. Finally, an inherently cleaner organic adsorbent to replace the current lignite-based activated carbon, and a non-separable replacement for the separable mixed ion exchange resin are undergoing evaluation. These efforts are undertaken to enhance the performance and reduce the risk associated with operations to ensure the long-term health of the EMU cooling water circuit.

Steele, John↗

NASA NTRS2017

Status of the Redesign of the Extravehicular Mobility Unit Airlock Cooling Loop Recovery Assembly

During EVA (Extravehicular Activity) 23 aboard the ISS (International Space Station) on 07/16/2013 an episode of water in the EMU (Extravehicular Mobility Unit) helmet occurred, necessitating a termination of the EVA (Extravehicular Activity) shortly after it began. The root cause of the failure was determined to be ground-processing short-comings of the ALCLR Ion Beds which led to various levels of contaminants being introduced into the Ion Beds before they left the ground. The Ion Beds were thereafter used to perform on-orbit routine scrubbing operations for the EMU cooling water loop which led to the failure. The root cause investigation identified several areas for improvement of the ALCLR Assembly which have since been initiated. Enhanced washing techniques for the ALCLR Ion Bed have been developed and implemented. On-orbit cooling water conductivity and pH analysis capability to allow the astronauts to monitor proper operation of the ALCLR Ion Bed during scrubbing operation have been investigated and are being incorporated. A simplified means to acquire on-orbit EMU cooling water samples has been designed as well. Finally, an inherently cleaner organic adsorbent to replace the current lignite-based activated carbon, and a non-separable replacement for the separable mixed ion exchange resin have been selected. These efforts are being undertaken to enhance the performance and reduce the risk associated with operations to ensure the long-term health of the EMU cooling water circuit. The intent of this paper is to provide an update of the effort to re-design the ALCLR (Airlock Cooling Loop Recovery) hardware. Last year, this effort was in the early stages of concept development and test which was reported in ICES Paper ICES-2016-221. Those phases are now complete and the final outcomes, as well as plans to build and field the hardware, are being reported on.

Steele, John↗

NASA NTRS1972

Preliminary design of a Primary Loop Pump Assembly (PLPA), using electromagnetic pumps

A preliminary design study of flight-type dc conduction-permanent magnetic, ac helical induction, and ac linear induction pumps for circulating 883 K (1130 F) NaK at 9.1 kg/sec (20 lb/sec) is described. Various electromagnetic pump geometrics are evaluated against hydraulic performance, and the effects of multiple windings and numbers of pumps per assembly on overall reliability were determined. The methods used in the electrical-hydraulic, stress, and thermal analysis are discussed, and the high temperature electrical materials selected for the application are listed.

Moss, T. A.↗

NASA NTRS2003

Deployable radiator with flexible line loop

Radiator assembly (10) for use on a spacecraft (12) is provided including at least one radiator panel assembly (26) repeatably movable between a panel stowed position (28) and a panel deployed position (36), at least two flexible lines (40) in fluid communication with the at least one radiator panel assembly (26) and repeatably movable between a stowage loop (42) and a flattened deployed loop (44).

Keeler, Bryan V.↗

NASA NTRS2004

Sabatier Carbon Dioxide Reduction Assembly Development for Closed Loop Water Recovery

The Sabatier Carbon Dioxide Reduction System (CRA) offers water recovery on a long duration space mission to reduce water resupply. Currently, NASA Johnson Space Center (JSC), NASA Marshall Space Flight Center (MSFC), Hamilton Sundstrand Space Systems International, Inc. (HSSSI), and Southwest Research Institute (SWRI) are working together to develop a Sabatier CRA for the International Space Station (ISS). This effort is being funded by the Office of Biological and Physical Research (Code U)/Advanced Life Support program which is administered by NASA JSC. The Sabatier CRA is the next step in closing the oxygen life support loop on future space missions. The Sabatier reaction combines the waste carbon dioxide (recovered from crew metabolism) with waste hydrogen (a byproduct of electrolysis to produce oxygen) to produce water and methane (CH4). On ISS, the methane would be vented overboard, however the methane can be utilized for propulsion during a planetary exploration mission. Based on a crew size of 7-equivalent people, the Sabatier CRA can produce as much a 2000 lb/year water. Use of the Sabatier CRA will significantly reduce the amount of water that needs to be resupplied to the ISS on a yearly basis, at a tremendous cost saving to the program. Additionally, by recycling this additional water, the Sabatier CRA enables additional launch capacity for science experiments to be brought up to the ISS. The NASA/Industry team noted above has been working to reduce technical risks associated with the Sabatier CRA system. To date the technical risks have been considerably reduced, bringing the Technology Readiness Level (TRL) from TRL 4 to TRL 5/6. In doing so, the team has developed the system schematic, system models, control scheme, produced engineering development unit (EDU) hardware, performed limited integration testing of the EDU's and verified system modeling through testing. Additionally, the system schematic has been evaluated for failure modes and hazards and had a successful technical review by the NASA Safety Board. The current focus is now related to development of the water/methane phase separator, liquid sensor and CO2 compressor piston seal life. The overall goal of the current effort is to bring the system up to a TRL6 by the end of GFY04. Although the Sabatier CRA is not currently baselined for use on the ISS, its benefits are significant enough such that volume within the Oxygen Generation System rack has been reserved for future installation. The value of the water the CRA recover will allow NASA the additional crew time and payload needed to pursue its mission of scientific research.

Smith, Frederick↗

NASA NTRSDate not supplied

Development and Application of Weld Track Thermal Analysis for the Exploration Extravehicular Mobility Unit

NASA is studying the next generation of space suit for safe operations in space, from the International Space Station to the lunar surface as part of the Exploration Extravehicular Mobility Unit project. The backplate structure of the portable life support system (PLSS) serves as the attachment point for assembly of the PLSS and contains embedded cooling channels. The thermal loop plumbing assembly and backplate are combined into a single component such that the fluid lines run through the midplane of the backplate. The manufacturing of the Ti-6Al-4V backplate consists of machining channels into a plate, welding cover plates on each channel using an electron beam, and additional machining for excess material removal and final detail. Careful control of the electron beam weld process is necessary to completely seal cover plates, produce consistent weld tracks, and produce channels with uniform cross sections free of debris and defects. The backplate contains multiple weld channels with unique geometries. The weld process parameters include choosing the beam current and focus, accelerating voltage, travel speed, pause times between weld tracks, and sequence of weld tracks. A transient finite element thermal analysis was developed to provide support for choosing and controlling the weld process parameters to maintain a consistent melt pool along each of the weld tracks. A moving distributed heat source is modeled to represent the heat input generated by the electron beam. The heat source model is a critical input to the analysis for accurate temperature predictions during the weld process. A modified conical heat source was developed to account for the change in working distance between the backplate and cover plates. The geometry of the material being welded must be accounted for by the heat source model to define the correct energy input. The weld process control is designed according to the predicted thermal history and melt pool dimensions for each of the weld channels. The analysis model, modified heat source, temperature and melt pool predictions, application of the thermal data to the weld parameters, and comparison with micrograph cross-sections from weld trials will be discussed in this presentation.

Electron Beam Welding↗

NASA NTRS1997

Evaluation of Assembly Simulators Used in Closed Loop Attitude Control System Testing

The Cassini Spacecraft's Attitude and Articulation Control Subsystem has been tested extensively at the Jet Propulsion Laboraroty in Pasadena, California. Three of the subsystem's assemblies have been tested using assembly simulators in place of actural hardware.

Cassini Attitude Articulation↗

NASA NTRSDate not supplied

Hardware-in-the-Loop Simulation of Modular Antenna Assembly

Robots are playing an increasing role in space exploration and in-space servicing. Robotic arms are good for performing in-space tasks such as modular assembly. The SPIDER arm (SPace Infrastructure Dexterous Robot) of the OSAM-1 mission represents an example of a system that can perform modular antenna assembly tasks in environmental conditions that would be dangerous for astronauts. One of the WVRTC activities is to perform independent verification and validation of the SPIDER assembly operations. Space robotic systems adopting large manipulators such as the SPIDER arm are complex to test and verify under normal 1-G conditions. Our work involves proof-of-principle testing of a hardware-inthe-loop (HIL) simulator operating in 1-g conditions, which replicates the motion of the space robot end-effector under the same geometric, kinematic and dynamic conditions, and in response to externally applied forces from its space environment. In particular, our software simulates in real-time the robot dynamics inclusive of flexibility, an important aspect in case of a long robotic arms operating in 0-G conditions. For example, the same oscillatory motions of the space manipulator’s end-effector can be mimicked on ground through our industrial manipulator, allowing us to test the feasibility of complex operation such as assembling modular components.

Robotic Assembly↗

NASA NTRS1987

Measurement technique of the Giotto radio science experiment

The paper describes the technique used to record time delay and waveform measurements for the Giotto radio science experiment of ESA's mission to comet Halley. The data were taken by using either two-way measurements (during pre- and post-encounter) or one-way measurements (during encounter with comet Halley), the downlink of the radio signal of the Giotto spacecraft being received at 8.4 GHz by the 64 m tracking stations of NASA's Deep Space Network (DSN). The waveform measurements were obtained at a sampling frequency of 50 kHz with an open-loop receiver assembly at DSN station Canberra as recently used for the Voyager/Uranus fly-by. Performance and calibration data are given as relevant to the radio subsystems on the ground and aboard Giotto.

Edenhofer, P.↗

NASA NTRS1991

Nuclear light bulb

The nuclear light bulb engine is a closed cycle concept. The nuclear light bulb concept provides containment by keeping the nuclear fuel fluid mechanically suspended in a cylindrical geometry. Thermal heat passes through an internally cooled, fused-silica, transparent wall and heats hydrogen propellant. The seeded hydrogen propellant absorbs radiant energy and is expanded through a nozzle. Internal moderation was used in the configuration which resulted in a reduced critical density requirement. This result was supported by criticality experiments. A reference engine was designed that had seven cells and was sized to fit in what was then predicted to be the shuttle bay mass and volume limitations. There were studies done of nozzle throat cooling schemes to remove the radiant heat. Elements of the nuclear light bulb program included closed loop critical assembly tests done at Los Alamos with UF6 confined by argon buffer gas. It was shown that the fuel region could be seeded with constituents that would block UV radiation from the uranium plasma. A combination of calculations and experiments showed that internal moderation produced a critical mass reduction. Other aspects of the research are presented.

Latham, Tom↗

NASA NTRS2010

Design and Development of a Regenerative Blower for Space Suit Ventilation

The ventilation subsystem in future space suits will require a dedicated ventilation fan. The unique requirements for the ventilation fan, including stringent safety requirements and the ability to increase output to operate in buddy mode, combine to make a regenerative blower an attractive technology choice. This paper describes progress in the design, development, and testing of a regenerative blower designed to meet requirements for a ventilation subsystem for future space suit life support. Analysis methods were developed for the blower s complex internal flows and impeller geometries were identified that enable significant improvements in blower efficiency. Performance predictions were verified by test, measuring aerodynamic efficiencies of 45% at operating conditions that correspond to the ventilation fan s design point. A compact motor/controller was developed to drive the blower efficiently at low rotating speed (4500 rpm). Finally, a low-pressure oxygen test loop was assembled to demonstrate the blower s reliability under prototypical conditions.

Izenson, Mike↗

NASA NTRSDate not supplied

Hardware-in-the-Loop Simulation of Modular Antenna Assembly

Space Assembly↗

NASA NTRS2004

A Selected Operational History of the Internal Thermal Control System (ITCS) for International Space Station (ISS)

The Internal Thermal Control System (ITCS) has been developed jointly by Boeing Corporation, Huntsville, Alabama and Honeywell Engines & Systems, Torrance, California to meet the internal thermal control needs for the International Space Station (ISS). The ITCS provides heat removal for the critical life support systems and thermal conditioning for numerous experiment racks. The ITCS will be fitted on a number of modules on the ISS. The first US Element containing the ITCS, Node 1, was launched in December 1998. Since Node 1 does not contain a pump to circulate the fluid it was not filled with ITCS fluid until after the US Laboratory Module was installed. The second US Element module, US Laboratory Module, which contains the pumps and all the major ITCS control hardware, was launched in February 2001. The third US Element containing the ITCS, the US Airlock, was launched in July 2001. The dual loop system of the ITCS is comprised of a lowtemperature loop (LTL) and a moderate-temperature loop (MTL). Each loop has a pump package assembly (PPA), a system flow control assembly (SFCA), a threeway mixing valve (TWMV), several rack flow control assemblies (RFCA), cold plates, pressure sensors, temperature sensors, pump bypass assembly (PBA) and a heat exchanger. In addition, the MTL has an additional TWMV, a payload regeneration heat exchanger (P/RHE) and a manual flow control valve (MFCV). The LTL has a service performance and checkout unit (SPCU) heat exchanger. The two loops are linked via one loop crossover assembly (LCA) providing cross loop capabilities and a single PPA, two-loop functionality. One important parameter monitored by the ground stations and on-orbit is the amount of fluid leakage from the ITCS. ISS fluid leakage is of importance since ITCS fluid is costly to re-supply, may be difficult to clean up in zero-g, and if uncontained could lead to equipment failures and potential hazards. This paper examines the nominal leakage observed over period of a year of on-orbit operation and compares this with analysis predictions. This paper also addresses the off-nominal leakage and a fluid transfer event causing significant changes in accumulator quantity.

Patel, Vipul P.↗

NASA NTRS2024

Short Exploration Extravehicular Mobility Unit Testing Setup: Evaluation Under Realistic Pressure and Thermal Conditions

The purpose of Short Exploration Extravehicular Mobility Unit (SxEMU) thermal vacuum testing was to verify the functionality of the Design Verification Testing (DVT) prototype xEMU (SxEMU for this test) at vacuum pressures and extreme space and lunar surface temperature conditions. The SxEMU Thermal Vacuum Test was the culmination of the DVT xEMU project. This paper’s focus is on the pre-Extravehicular Activity (EVA) test setup, and general performance of the SxEMU Portable Life Support Subsystem (xPLSS), with focus on the performance of the Primary Oxygen Assembly (POA) and Secondary Oxygen Assembly (SOA), including Secondary Oxygen Regulator (SOR) takeover and the POA and SOA low-setpoint change inhibit. The initial pre-EVA test preparation included recharging the batteries and replenishing consumables, including test-system water, oxygen assemblies (with gaseous nitrogen), and the integrated thermal loops, including the Feedwater Supply Assemblies. xPLSS functionality testing included carbon dioxide (CO2) removal via the Rapid Cycle Amine swingbed system, thermal loop temperature control, and monitoring of suit ventilation loop pressure, temperature, and CO2 percentages. Testing evaluated automatic takeover of suit pressure control by the SOR after the primary oxygen supply is depleted. The Primary Oxygen Regulator and SOR low-setpoint change inhibit function prevents the crewmember from inadvertently setting the primary regulator to a low pressure setpoint during an EVA.

xPLSS↗

NASA NTRS2011

Propulsive Reaction Control System Model

This software models a propulsive reaction control system (RCS) for guidance, navigation, and control simulation purposes. The model includes the drive electronics, the electromechanical valve dynamics, the combustion dynamics, and thrust. This innovation follows the Mars Science Laboratory entry reaction control system design, and has been created to meet the Mars Science Laboratory (MSL) entry, descent, and landing simulation needs. It has been built to be plug-and-play on multiple MSL testbeds [analysis, Monte Carlo, flight software development, hardware-in-the-loop, and ATLO (assembly, test and launch operations) testbeds]. This RCS model is a C language program. It contains two main functions: the RCS electronics model function that models the RCS FPGA (field-programmable-gate-array) processing and commanding of the RCS valve, and the RCS dynamic model function that models the valve and combustion dynamics. In addition, this software provides support functions to initialize the model states, set parameters, access model telemetry, and access calculated thruster forces.

Brugarolas, Paul↗

NASA NTRS2003

Integrated Testing of a Carbon Dioxide Removal Assembly and a Temperature-Swing Adsorption Compressor for Closed-Loop Air Revitalization

Accumulation and subsequent compression of carbon dioxide that is removed from space cabin are two important processes involved in a closed-loop air revitalization scheme of the International Space Station (ISS). The carbon dioxide removal assembly (CDRA) of ISS currently operates in an open loop mode without a compressor. This paper describes the integrated test results of a flight-like CDRA and a temperature-swing adsorption compressor (TSAC) for carbon dioxide removal and compression. The paper provides details of the TSAC operation at various CO2 loadings and corresponding performance of CDRA.

Knox, J. C.↗