NASA Small Business Innovative Research Research Articles

Redox Tolerant Solid Oxide Electrolysis Cathode for CO2 and Steam

The production of oxygen for life support and ascent vehicle propellant oxidant is essential for human expeditions to Mars. OxEon team led the development of solid oxide electrolysis cell (SOEC) stacks for the Mars 2020 mission in collaboration with the Jet Propulsion Laboratory (JPL) and Massachusetts Institute of Technology (MIT). A stack that was installed in the Perseverance Rover has been operated twelve times so far to demonstrate the production of high purity oxygen by electrolyzing Mars atmosphere CO2.Traditionally, SOEC stacks use nickel–zirconia or nickel–ceria composite cathode to reduce the oxidized species. Nickel based electrodes are susceptible to oxidation by the feed gas (CO2 or steam) at the inlet conditions and are often irreversibly damaged during operation and start-up unless reduced species (carbon monoxide or hydrogen) are also present. Oxidation of Ni to NiO causes ~24% volume expansion, and a redox cycle with associated expansion and contraction can result in significant changes to the microstructure and loss of connectivity in the cathode and current collection layers. This challenge was encountered during early stack and testing development for the Mars mission where even short-term exposure to oxidizing dry CO2 feed caused massive performance degradation (12% of initial performance after 15 operational cycles). This necessitated a recycle loop for the stack on the Perseverance Rover that introduces a fraction of the CO-containing tail gas to the inlet to protect the cathode layers from oxidation.A simpler solution than a system recycle loop was desired for future applications. Under a NASA SBIR program OxEon investigated a combination of materials and engineering solutions to improve redox tolerance of the nickel-based cathode so that 100% dry CO2 could be fed directly into a stack without harming the electrode. A modified nickel-based cathode composition with a unique backbone and infiltrated cathode structure was developed and tested in both button cell and stack configurations. The new cathode has been shown to completely tolerate partial and full (i.e., complete oxidation of Ni to NiO before re-reduction) redox cycling, with complete performance recovery occurring in a matter of minutes even after total oxidation. It was also demonstrated that feeding a reducing gas after complete oxidation is not required since the CO generated by the applied voltage during initial CO2 electrolysis reaction is sufficient for self-reduction recovery. This self-recovery feature is particularly attractive for applications where an oxidizing gas feed cannot be easily substituted with a reducing gas feed, such as with Mars O2 generation.In-situ resource utilization (ISRU) of lunar ice and potential Martian ice for O2 and H2 generation is also of significant interest for future space missions. The redox tolerant cathode has been shown to completely tolerate steam oxidation as well, with self-generated H2 resulting in rapid reduction and recovery. Steam redox tolerance was demonstrated in both button cells and stacks and was independently verified by testing at PNNL. The redox tolerant cathode is also capable of rapid thermal cycling with ramp rates as high as 15 °C/min tested with no performance degradation. Improved coking tolerance over the traditional cathode material is an additional robustness feature that allows for higher conversion of CO2, enabling increased O2 production.This work was done under a NASA Small Business Innovation Research Contract No. 80NSSC19C0114. Validation testing at PNNL was performed under a DOE Award No. DE-FE0032105.

(Invited) Electrochemical Production of Oxygen and Fuel on Mars

The production of oxygen for life support and ascent vehicle propellant oxidant is essential for human expeditions to Mars. Solid oxide electrolysis (SOXE) stacks are capable of reducing carbon dioxide and water available on Mars to produce high purity oxygen. They can electrolyze CO2 or water separately or co-electrolyze CO2 and water together to produce oxygen and fuels such as methane for propulsion. OxEon’s team led the development of SOXE stacks in collaboration with the Jet Propulsion Laboratory (JPL) and Massachusetts Institute of Technology (MIT). The work resulted in delivering a set of flight qualified stacks to JPL. A packaged stack has been installed on the rover that is scheduled for launch next year for the Mars 2020 mission. The Mars Oxygen ISRU Experiment (MOXIE) will demonstrate the feasibility of producing high purity oxygen from Mars atmosphere carbon dioxide using a SOXE stack. Since delivering the stacks, the OxEon team has designed and begun fabricating SOXE stacks of the cell area required for a manned Mars mission. Under the NASA NextSTEP-2 ISRU activity, this platform will be tested with conditions targeting the ISRU application. MOXIE testing was focused on the case of atmospheric ISRU for oxygen evolution at the anode and did not make use of the CO byproduct gas at the cathode.. In 2019, OxEon will demonstrate CO2-steam co-electrolysis to produce carbon monoxide and hydrogen (synthesis gas) on the cathode and high purity oxygen at the anode. The synthesis gas will be converted to methane in an OxEon developed methanation reactor as an alternative to a water electrolysis coupled Sabatier system. In addition, OxEon is investigating a combination of materials and engineering solutions to improve redox tolerance of nickel-based cathode. Traditionally, SOXE stacks use nickel – zirconia or nickel – ceria composite cathode. Nickel based electrodes are susceptible to oxidation by the feed gas (CO2 or steam) at the inlet conditions unless reducing species (carbon monoxide or hydrogen) are also present. Button cell tests show that the new, modified cathode material exhibits good redox stability over multiple redox cycles with only a minor loss of performance after each cycle. Initial tests also show that under certain operating conditions the loss of performance can be recovered. Implementation of a redox tolerant cathode will eliminate the need for complex recycle loop that introduces a fraction of the product gases to the inlet in order to prevent nickel oxidation. Acknowledgement: NextSTEP ISRU work is supported under NASA Contract 8-HQTR19C0006. The redox tolerant cathode work is done under a NASA Small Business Innovation Research Contract No. 80NSSC18P1940. The work related to MOXIE was based on support from NASA through JPL’s prime contract, under JPL subcontract number 1515459.

Strained-layer-superlattice-based compact thermal imager for the International Space Station.

The compact thermal imager (CTI) is a dual-band, strained-layer-superlattice (SLS) detector-based instrument that was installed on the exterior of the International Space Station (ISS) in conjunction with the third Robotic Refueling Mission 3 (RRM3) in 2018. The CTI serves as a pathfinder for future thermal infrared capability on Landsat. The CTI incorporates an SLS hybrid, a dual-band 3-5 and 8-10 μm, electrically switchable, 320×256 array with 30 μm2 pixels, bonded to an Indigo ISC0903 Readout Integrated Circuit (ROIC). The telescope was built around an integrated detector cryocooler assembly developed under a NASA Small Business Innovative Research award with QmagiQ, LLC. The cooler is a Ricor K508 and the front-end optics is a custom-designed, doublet lens telescope with a 150 mm focal length. The ground resolution is 80 meters/pixel from the ISS altitude of 400 km. A filter creates two spectral channels from the dual bands, 3.3-5.4 and 7.8-10.2 μm. The detector hybrid control electronics is a custom-developed system based on the Teledyne Imaging Systems SIDECAR Application-Specific Integrated Circuit. This module provides the electronic interface from the RRM3 SpaceCube on-board processor to the detector/ROIC assembly. The primary goal of this mission was to perform a technology demonstration of the SLS technology and the commercial cooler technology elevating the Technology Readiness Level (TRL) to TRL 9 on a bare-bones budget and relatively fast development cycle. Some science objectives include locating fires, approximating land surface temperatures, and monitoring evapotranspiration, sea ice, and glacier dynamics. In this paper, we will present the design of the focal plane, optics, electronics, and mechanical structure of the CTI. We will also describe the operation and qualification tests that were performed to bring the CTI to the NASA TRL 6 in preparation for the launch on a SpaceX Dragon from the Kennedy Space Center.

Development of a Human Factors Principles-Based Design Tool for Engineers

Designing for users involves many challenges, including understanding the situation in which the end users will be working. In a recent NASA Small Business Innovative Research effort, a research team developed a software tool to help engineers and human factors specialists share human factors information and project-specific data. The resulting product was a software tool called the Human Factors Analysis Support Tool (H-FAST). This paper describes a project to provide a proof of concept to extend H-FAST’s capabilities. In this effort, we developed the Automated Guidance Assessment Tool (AGAT). AGAT assesses a control panel design in terms of its adherence to human factors principles, and provides relevant feedback to engineers in the form of targeted recommendations and access to relevant human factors standards.

Evaluating the NASA small business innovation research program: preliminary evidence of a trade-off between commercialization and basic research

In 1982, the Small Business Innovation Development Act established the small business innovation research (SBIR) program. This program reserves a percentage of federal agencies’ extramural R&D budgets for research projects conducted by small businesses. When this Act was reauthorized in 1992, the selection criteria for funding dramatically increased the likelihood of funding for projects that promised to lead to commercial success. Using data from a survey of the SBIR program award recipients at NASA Langley Research Center, we address three questions about this change: (i) was there a shift to projects with more commercial potential? (ii) did these projects experience higher rates of commercial success? and (iii) was there a reduction in basic research accompanying the increased commercial success? Our analysis suggests, the answer to all three of these questions is ‘yes’.

2K×2K resolution element photon counting MCP sensor with >200 kHz event rate capability

Siegmund Scientific undertook a NASA Small Business Innovative Research (SBIR) contract to develop a versatile, high-performance photon (or particle) counting detector combining recent technical advances in all aspects of Microchannel Plate (MCP) detector development in a low cost, commercially viable package that can support a variety of applications. The detector concept consists of a set of MCPs whose output electron pulses are read out with a crossed delay line (XDL) anode and associated high-speed event encoding electronics. The delay line anode allows high-resolution photon event centroiding at very high event rates and can be scaled to large formats (>40 mm) while maintaining good linearity and high temporal stability. The optimal sensitivity wavelength range is determined by the choice of opaque photocathodes. Specific achievements included: spatial resolution of <25μm FWHM; formats from 25 to 40 mm with digitized pixel sizes of ∼3μm; total detector rates of >200000 events s−1; local rates of >100 eventss−1 per resolution element; event timing of <1ns; and low background counting rates (<1 event cm−2s−1).

EXOS research on the design of haptic interface and force reflective controller

EXOS had developed two state-of-the-art prototype master controllers for controlling robot hand and manipulators under the Small Business Innovation Research (SBIR) program with NASA. One of such devices is a two degree-of-freedom (DOF) sensory and force reflecting exoskeleton (SAFiRE) which is worn on the hand of a human operator. It measures the movement of the human finger and reflects the interaction forces between the slave robot hand and the environment back to the human finger. The second device is a position sensing Exoskeleton ArmMasterTM (EAM) that is worn on the human operator’s arm. This device simultaneously tracks the motions of the operator’s three DOF shoulder and two DOF elbow. Both of these devices are currently controlling robots at NASA. Currently, a five-fingered SAFiRE and a force reflecting EAM are being developed under two phase II NASA SBIR grants. This paper will include discussion of: (1) the design of the current prototypes, (2) phase II project objectives, (3) human haptic interface design issues that must be addressed, (4) progress to date in addressing these issues.