NASA SBIR/STTR Successes, Opportunities, and Pathways for EVA
This presentation discusses NASA's SBIR/STTR Program including its goals, process, successes, opportunities, and pathways.
Chullen, Cinda↗
Engineering topics
Chullen, Cinda
Publications and source records attributed to Chullen, Cinda.
Monolithic Trace-Contaminant Sorbents Fabricated from 3D-Printed Polymer Precursors
The current trace-contaminant (TC) removal technology for use in Extravehicular Activities (EVAs) involves the use of a packed bed of acid-impregnated granular charcoal, which is difficult to regenerate. In this paper, results are presented on the development of vacuum-regenerable TC sorbents for use in the Portable Life Support System (PLSS). The sorbents are derived from 3D-printed polymer monoliths (e.g., honeycomb structures), which are then carbonized and activated in order to develop porosity, and also to enhance the TC-sorption capacity. Results are presented on the following aspects of carbon-sorbent development: (1) precursor selection; (2) monolith fabrication; (3) shape retention and strength; (4) carbon surface and porosity characterization; (5) TC-sorption capacity and vacuum-regeneration; (6) pressure drop; and (7) sub-scale sorbent prototype. The use of predominantly microporous monolithic carbon is associated with the following benefits: (a) high TC-sorption capacity; (b) low pressure drop; (c) rapid vacuum (pressure-swing) desorption due to thin monolith walls and low pressure drop; (d) good thermal management (high thermal conductivity and low adsorption/desorption thermal effects associated with physisorption); and (e) good resistance to dusty environments.
Portable Life Support System (PLSS)↗
Low-Power, Chip-Scale, Carbon Dioxide Gas Sensors for Spacesuit Monitoring
N5 Sensors, Inc. through a Small Business Technology Transfer (STTR) contract award has been developing ultra-small, low-power carbon dioxide (CO2) gas sensors, suited for monitoring CO2 levels inside NASA spacesuits. Due to the unique environmental conditions within the spacesuits, such as high humidity, large temperature swings, and operating pressure swings, measurement of key gases relevant to astronaut's safety and health such as(CO2), is quite challenging. Conventional non-dispersive infrared absorption based CO2 sensors present challenges inside the spacesuits due to size, weight, and power constraints, along with the ability to sense CO2 in a high humidity environment. Unique chip-scale, nanoengineered chemiresistive gas-sensing architecture has been developed for this application, which can be operated in a typical space-suite environmental conditions. Unique design combining the selective adsorption properties of the nanophotocatalytic clusters of metal-oxides and metals, provides selective detection of CO2 in high relative humidity conditions. All electronic design provides a compact and low-power solution, which can be implemented for multipoint detection of CO2 inside the spacesuits. This paper will describe the sensor architecture, development of new photocatalytic material for better sensor response, and advanced structure for better sensitivity and shorter response times.
Rani, Asha↗
Sensor Integrated Pilot Mask for On-Board, Real-Time, Monitoring of Pilot Breathing Gas
A pilot's job is unique in the demands it places on the human body, and many conditions can seriously affect pilot performance, threatening mission completion and pilot safety. The gas in a flight mask contains key indicators of the pilot's physiological state, including oxygen inhaled and carbon dioxide exhaled, which can signal hypoxia, hyperoxia, hypocapnia, and hypercapnia. A fiber optic-based sensor system, integrated into the pilot mask, has been developed to monitor in real time, during flight, the pilot breathing gas levels. Monitoring the partial pressure of oxygen and carbon dioxide in the pilot mask supports real-time closed loop control of the on-board oxygen generation system, based on a direct reading of what the pilot is actually breathing. The pilot Mask Sensor (MASES) system incorporates luminescence sensors for pO2, pCO2, relative humidity, pressure, and temperature in a compact probe in the pilot mask; it is based on sensor technology developed for gas monitoring in space suit systems, in work supported by NASA under the Small Business Innovation Research program. Relevant requirements for the MASES system include sensor operation while wet, operation at reduced pressure, ability to withstand rapid decompression, operation in a pure oxygen atmosphere, low power consumption, a compact readout unit, and flexible miniature sensors; many of these requirements are shared with gas monitors in space suits. Data are presented from tests conducted with human subjects in an altitude chamber and in a centrifuge.
Delgado Alonso, Jesus↗
Swing Bed Scrubber Design and Test Integration Results for Carbon Dioxide Removal in the Ventilation Test Loop 2.0
NASA is developing an advanced portable life support system (PLSS) to meet the needs of a new NASA advanced space suit. The PLSS provides the necessary oxygen, ventilation, and thermal protection for an astronaut performing a spacewalk. The PLSS ventilation subsystem is responsible for providing adequate carbon dioxide (CO2) and water vapor removal. To experimentally validate the performance of CO2 removal and advanced CO2 sensing systems, NASA Johnson Space Center developed the Ventilation Test Loop 2.0 (VTL2) and tested the Oceaneering Swing Bed Scrubber (SBS) that was fabricated and delivered under the Constellation Space Suit System Contract in 2015. The SBS was designed to continuously remove CO2 and water vapor from a space suit ventilation loop with a pair of thermally integrated amine beds that alternately adsorb and desorb water vapor and CO2. The SBS hardware was recently resurrected and reassembled to support a full battery of performance testing in the VTL2. This paper describes the design and development of the SBS and the VTL2 along with the performance test results of the SBS.
Ventilation Test Loop↗
Low-Power, Chip-Scale, CO2 Gas Sensors for Spacesuit Monitoring
N5 Sensors, Inc. and NASA through a STTR program are jointly developing ultra-small, low-power carbon dioxide (CO2) gas sensors, suited for monitoring CO2 levels inside the spacesuits. Due to the unique environmental conditions within the spacesuits, such as high humidity, large temperature and operating pressure swings, measurement of key gases relevant to astronaut's safety and health such as carbon dioxide, is quite challenging. Conventional non-dispersive infrared absorption based CO2 sensors cannot be effectively implemented inside the spacesuits due to their sizes, weights, and power constraints. Metal-oxide based sensors have been effectively miniaturized for several applications, however detection of CO2 utilizing metal-oxide based sensors is challenging due to the chemical inertness and high stability of CO2 at room-temperatures. To mitigate these limitations, unique chip-scale, nanoengineered chemiresistive gas-sensing architecture has been developed - to allow the Metal-oxide sensors to operate in space-suite environmental conditions. Unique design combining the selective adsorption properties of the nanophotocatalytic clusters of metal-oxides and metals, provides selective detection of CO2 in high relative humidity conditions. All electronic design provides a compact and low-power solution, which can be implemented for multipoint detection of CO2 inside the spacesuits. This paper will describe a novel approach in refining the sensor architecture, development of new photocatalytic material for better sensor performance.
Thomson, Brian↗
Sensors and Systems for Spacesuits
An AdvancedExtravehicular Mobility Unit (EMU) is being developed and tested in house at JSC. Multiple programs over the last decade have contributed to the success thus far including the SBIR/STTR program.
Chullen, Cinda↗
Development Requirements for the Exploration PLSS (xPLSS) Carbon Dioxide and Humidity Control Unit (CDHCU)
Functional Requirements for the Carbon Dioxide and Humidity Control Unit (CDHCU): The CDHCU is a component of the Exploration Portable Life Support System (xPLSS) to provide carbon dioxide (CO2) and humidity control within the spacesuit for a crewmember to perform extravehicular activities (EVA) in vacuum (micro-g), lunar, and Mars environments for up to 8 hours continuous, and during EVA preparation in airlocks or support vehicles for an additional 2 hours (TBR) continuous.
Chullen, Cinda↗
Results from Carbon Dioxide Washout Testing Using a Suited Manikin Test Apparatus with a Space Suit Ventilation Test Loop
NASA is developing an advanced portable life support system (PLSS) to meet the needs of a new NASA advanced space suit. The PLSS is one of the most critical aspects of the space suit providing the necessary oxygen, ventilation, and thermal protection for an astronaut performing a spacewalk. The ventilation subsystem in the PLSS must provide sufficient carbon dioxide (CO2) removal and ensure that the CO2 is washed away from the oronasal region of the astronaut. CO2 washout is a term used to describe the mechanism by which CO2 levels are controlled within the helmet to limit the concentration of CO2 inhaled by the astronaut. Accumulation of CO2 in the helmet or throughout the ventilation loop could cause the suited astronaut to experience hypercapnia (excessive carbon dioxide in the blood). A suited manikin test apparatus (SMTA) integrated with a space suit ventilation test loop was designed, developed, and assembled at NASA in order to experimentally validate adequate CO2 removal throughout the PLSS ventilation subsystem and to quantify CO2 washout performance under various conditions. The test results from this integrated system will be used to validate analytical models and augment human testing. This paper presents the system integration of the PLSS ventilation test loop with the SMTA including the newly developed regenerative Rapid Cycle Amine component used for CO2 removal and tidal breathing capability to emulate the human. The testing and analytical results of the integrated system are presented along with future work.
Chullen, Cinda↗
Advanced Supported Liquid Membranes for Carbon Dioxide Control in Cabin Applications
The development of new, robust, life support systems is critical to NASA's continued progress in space exploration. One vital function is maintaining the carbon dioxide (CO2) concentration in the cabin at levels that do not impair the health or performance of the crew. The CO2 removal assembly (CDRA) is the current CO2 control technology on-board the International Space Station (ISS). Although the CDRA has met the needs of the ISS to date, the repeated cycling of the molecular sieve sorbent causes it to break down into small particles that clog filters or generate dust in the cabin. This reduces reliability and increases maintenance requirements. Another approach that has potential advantages over the current system is a membrane that separates CO2 from air. In this approach, cabin air contacts one side of the membrane while other side of the membrane is maintained at low pressure to create a driving force for CO2 transport across the membrane. In this application, the primary power requirement is for the pump that creates the low pressure and then pumps the CO2 to the oxygen recovery system. For such a membrane to be practical, it must have high CO2 permeation rate and excellent selectivity for CO2 over air. Unfortunately, conventional gas separation membranes do not have adequate CO2 permeability and selectivity to meet the needs of this application. However, the required performance could be obtained with a supported liquid membrane (SLM), which consists of a microporous material filled with a liquid that selectively reacts with CO2 over air. In a recently completed Phase II SBIR project, Reaction Systems, Inc. fabricated an SLM that is very close to meeting permeability and selectivity objectives for use in the advanced space suit portable life support system. This paper describes work carried out to evaluate its potential for use in spacecraft cabin application.
Wickham, David T.↗
U.S. Spacesuit Knowledge Capture Accomplishments in Fiscal Year 2015
The NASA U.S. Spacesuit Knowledge Capture (SKC) Program continues to capture, share, and archive significant spacesuit-related knowledge with engineers and other technical staff and invested entities. Since its 2007 inception, the SKC Program has hosted and recorded more than 65 events. By the end of Fiscal Year (FY) 2015, 40 of these were processed and uploaded to a publically accessible NASA Web site where viewers can expand their knowledge about the spacesuit's evolution, known capability and limitations, and lessons learned. Sharing this knowledge with entities beyond NASA can increase not only more people's understanding of the technical effort and importance involved in designing a spacesuit, it can also expand the interest and support in this valuable program that ensures significant knowledge is retained and accessible. This paper discusses the FY 2015 SKC events, the release and accessibility of the approved events, and the program's future plans.
Chullen, Cinda↗
Optical Breath Gas Extravehicular Activity Sensor for the Advanced Portable Life Support System
The function of the infrared gas transducer used during extravehicular activity (EVA) in the current space suit is to measure and report the concentration of carbon dioxide (CO2) in the ventilation loop. The next generation portable life support system (PLSS) requires highly accurate CO2 sensing technology with performance beyond that presently in use on the International Space Station extravehicular mobility unit (EMU). Further, that accuracy needs to be provided over the full operating pressure range of the suit (3 to 25 psia). Accommodation within space suits demands that optical sensors meet stringent size, weight, and power requirements. A laser diode (LD) sensor based on infrared absorption spectroscopy is being developed for this purpose by Vista Photonics, Inc. Version 1.0 prototype devices were delivered to NASA Johnson Space Center (JSC) in September 2011. The prototypes were upgraded with more sophisticated communications and faster response times to version 2.0 and delivered to JSC in July 2012. The sensors incorporate a laser diode based CO2 channel that also includes an incidental water vapor (humidity) measurement. The prototypes are controlled digitally with an field-programmable gate array microcontroller architecture. Based on the results of the iterative instrument development, further prototype development and testing of instruments were performed leveraging the lessons learned where feasible. The present development extends and upgrades the earlier hardware for the advanced PLSS 2.5 prototypes for testing at JSC. The prototypes provide significantly enhanced accuracy for water vapor measurement and eliminate wavelength drift affecting the earlier versions. Various improvements to the electronics and gas sampling are currently being advanced including the companion development of engineering development units that will ultimately be capable of radiation tolerance. The combination of low power electronics with the performance of a long wavelength laser spectrometer enables multi-gas sensors with significantly increased performance over that presently offered in the EMU.
Wood, William R.↗
Design and Development Comparison of Rapid Cycle Amine 1.0, 2.0, and 3.0
The development of the Rapid Cycle Amine (RCA) swing-bed technology for carbon dioxide (CO2) removal has been in progress since favorable results were published in 1996. Shortly thereafter, a prototype was designed, developed, and tested successfully and delivered to Johnson Space Center in 1999. An improved prototype was delivered to NASA in 2006 and was notated as RCA 1.0 and sized for the extravehicular activity (EVA). The new RCA swing-bed technology is a regenerative system which employs two alternating solid-amine sorbent beds to remove CO2 and water. The two- bed design employs a chemisorption process whereby the beds alternate between adsorbtion and desorbsion. This process provides for an efficient operation of the RCA so that while one bed is in adsorb (uptake) mode, the other is in the desorb (regeneration) mode. The RCA has now progressed through several iterations of technology readiness levels. Test articles have now been designed, developed, and tested for the advanced space suit portable life support system (PLSS) including RCA 1.0, RCA 2.0, and RCA 3.0. The RCA 3.0 was the most recent RCA fabrication and was delivered to NASA-JSC in June 2015. The RCA 1.0 test article was designed with a pneumatically actuated linear motion spool valve. The RCA 2.0 and 3.0 test articles were designed with a valve assembly which allows for switching between uptake and regeneration modes while minimizing gas volume losses to the vacuum source. RCA 2.0 and 3.0 also include an embedded controller design to control RCA operation and provide the capability of interfacing with various sensors and other ventilation loop components. The RCA technology is low power, small, and has fulfilled all test requirements levied upon the technology during development testing thus far. This paper will provide an overreview of the design and development of RCA 1.0, 2.0 and 3.0 including detail differences between the design specifications of each.
Chullen, Cinda↗
Continued Development of Compact Multi-gas Monitor for Life Support Systems Control in Space
Miniature optic gas sensors (MOGS) based on luminescent materials have shown great potential as alternatives to Near-Infrared-based gas sensor systems for the advanced space suit portable life support system (PLSS). The unique capability of MOGS for carbon dioxide and oxygen monitoring under wet conditions has been reported, as has the fast recovery of MOGS humidity sensors after long periods of being wet. Lower volume and power requirements are also potential advantages of MOGS over both traditional and advanced Non-Dispersive Infrared (NDIR) gas sensors, which have shown so far longer life than luminescent sensors. This paper presents the most recent results in the development and analytical validation of a compact multi-gas sensor unit based on luminescent sensors for the PLSS. Results of extensive testing are presented, including studies conducted at Intelligent Optical Systems laboratories, a United Technology Corporation Aerospace Systems (UTAS) laboratory, and a Johnson Space Center laboratory. The potential of this sensor technology for gas monitoring in PLSSs and other life support systems and the advantages and limitations found through detailed sensor validation are discussed.
Delgado-Alonso, Jesús↗
Portable Life Support System 2.5 Fan Design and Development
NASA is building a high-fidelity prototype of an advanced Portable Life Support System (PLSS) as part of the Advanced Exploration Systems Program. This new PLSS, designated as PLSS 2.5, will advance component technologies and systems knowledge to inform a future flight program. The oxygen ventilation loop of its predecessor, PLSS 2.0, was driven by a centrifugal fan developed using specifications from the Constellation Program. PLSS technology and system parameters have matured to the point where the existing fan will not perform adequately for the new prototype. In addition, areas of potential improvement were identified with the PLSS 2.0 fan that could be addressed in a new design. As a result, a new fan was designed and tested for the PLSS 2.5. The PLSS 2.5 fan is a derivative of the one used in PLSS 2.0, and it uses the same nonmetallic, canned motor, with a larger volute and impeller to meet the higher pressure drop requirements of the PLSS 2.5 ventilation loop. The larger impeller allows it to operate at rotational speeds that are matched to rolling element bearings, and which create reasonably low impeller tip speeds consistent with prior, oxygen-rated fans. Development of the fan also considered a shrouded impeller design that could allow larger clearances for greater oxygen safety, assembly tolerances and particle ingestion. This paper discusses the design, manufacturing and performance testing of the new fans.
Quinn, Gregory↗
Continued Development of Compact Multi-Gas Monitor for Life Support Systems Control in Space
Miniature optical gas sensors based on luminescent materials have shown great potential as alternatives to NIR-based gas sensor systems for the Portable Life Support System (PLSS). The unique capability of luminescent sensors for carbon dioxide and oxygen monitoring under wet conditions has been reported, as has the fast recovery of humidity sensors after long periods of being wet. Lower volume and power requirements are also potential advantages over both traditional and advanced non-dispersive infrared (NDIR) gas sensors, which have so far shown longer life than luminescent sensors. In this paper we present the most recent results in the development and analytical validation of a compact multi-gas sensor unit based on luminescent sensors for the PLSS. Results of extensive testing are presented, including studies conducted in Intelligent Optical Systems laboratories, a United Technologies Corporation Aerospace Systems (UTC) laboratory, and a Johnson Space Center laboratory. The potential of this sensor technology for gas monitoring in PLSSs and other life support systems, and the advantages and limitations found through detailed sensor validation are discussed.
Delgado-Alonso, Jesus↗
Results from Carbon Dioxide Washout Testing Using a Suited Manikin Test Apparatus with a Space Suit Ventilation Test Loop
NASA is developing an advanced portable life support system (PLSS) to meet the needs of a new NASA advanced space suit. The PLSS is one of the most critical aspects of the space suit providing the necessary oxygen, ventilation, and thermal protection for an astronaut performing a spacewalk. The ventilation subsystem in the PLSS must provide sufficient carbon dioxide (CO2) removal and ensure that the CO2 is washed away from the oronasal region of the astronaut. CO2 washout is a term used to describe the mechanism by which CO2 levels are controlled within the helmet to limit the concentration of CO2 inhaled by the astronaut. Accumulation of CO2 in the helmet or throughout the ventilation loop could cause the suited astronaut to experience hypercapnia (excessive carbon dioxide in the blood). A suited manikin test apparatus (SMTA) integrated with a space suit ventilation test loop was designed, developed, and assembled at NASA in order to experimentally validate adequate CO2 removal throughout the PLSS ventilation subsystem and to quantify CO2 washout performance under various conditions. The test results from this integrated system will be used to validate analytical models and augment human testing. This paper presents the system integration of the PLSS ventilation test loop with the SMTA including the newly developed regenerative Rapid Cycle Amine component used for CO2 removal and tidal breathing capability to emulate the human. The testing and analytical results of the integrated system are presented along with future work.
Chullen, Cinda↗