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Timothy Krause

Publications and source records attributed to Timothy Krause.

5 records
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Results of First Long Duration Space Flight of Hybrid Perovskite Thin Film

In support of NASA's Artemis program with the goal of a sustained human-lunar presence, there is a need for very large (>100kW) and high-voltage-capable solar arrays, estimated to cost over $150M. Perovskite-based thin-film photovoltaics offer substantial advantages over state-of-the-art solar arrays from the perspective of manufacturing large arrays. Perovskites have also demonstrated some of the lowest temperature coefficients and highest defect tolerance, which make them excellent candidates for aerospace applications. However, MHPs must demonstrate durability in space which presents different challenges than terrestrial operating environments. To decisively test the viability of perovskites being used in space, a perovskite thin film is positioned in low earth orbit for 10 months on the International Space Station, which was the first long-duration study of an MHP in space. Postflight high-resolution ultrafast spectroscopic characterization and comparison with control samples reveal that the flight sample exhibits superior photo-stability, no irreversible radiation damage, and a suppressed structural phase transition temperature by nearly 65 K, broadening the photovoltaic operational range. Further, significant photo-annealing of surface defects is shown following prolonged light-soaking postflight. These results emphasize that methylammonium lead iodide can be packaged adequately for space missions, affirming that space stressors can be managed as theorized.

William Delmas↗
NASA NTRSDate not supplied

An Experimental Study on Low Pressure Frost Formation for Lunar Polar Water Capture

In-situ resource utilization (ISRU) is a vital component of NASA’s mission to the Moon and beyond, as the extraction of resources from the environment can reduce payload weight and the frequency of resupply missions. Since the discovery of water in the regolith of the permanently shadowed regions (PSR) of the Moon, its extraction and transport has become an area of increasing interest for NASA. One proposed method is heating icy regolith to free the water before de-sublimating and transporting it as ice in a tanker. However, little is known regarding the dynamics of frost growth at low pressures, and an understanding of the heat transfer process is required to properly size the heat exchanger for the tanker. To investigate this phenomenon, a cold plate was placed in a vacuum chamber with water vapor directed at its surface. The chamber pressure (300 and 500 Pa) and cold plate temperature (–18 to –5 °C) were kept below the triple point and varied throughout the experiment to examine their impact on frost layer heat transfer. As water flowed into the chamber and deposited on the cold plate surface, the heat flux and temperature were measured along with the frost layer thickness and/or mass. Density calculated at the conclusion of each test suggests the frost layer is denser than that of frost grown at atmospheric pressure. The results demonstrate unexpected density and heat transfer characteristics and require development of a new model of frost growth for lunar conditions

Lunar polar↗
NASA NTRSDate not supplied

Fundamental Research to Enable In-Situ Resource Utilization for NASA’s Artemis Program and Beyond Taking Place at The Glenn Research Center

In Situ Resource Utilization (ISRU) is regarded by many to be the key to future sustainability in space. The National Aeronautics & Space Administration’s (NASA) Space Technology Mission Directorate (STMD) recently published a list of ranked technology shortfalls. ISRU specific capabilities of ‘Extraction and separation of water from extraterrestrial surface material’, ‘Extraction and separation of oxygen from extraterrestrial surface material’, and ‘Produce propellants and mission consumables from extracted in-situ resources’ are within the top 80 shortfalls identified. A team of researchers and engineers at NASA’s Glenn Research Center (GRC) in Cleveland, Ohio, are performing fundamental research and technology maturation to ensure concepts and technologies are ready to support when the mission architecture is primed for ISRU to activate. Through analytical modeling and initial lab-scale testing, researchers are establishing concepts that mature to more sophisticated tests in relevant environments. Numerous studies are underway assessing fundamental behaviors of regolith during various steps of a conceptual ISRU production plant. This paper shares some of GRC’s recent advancements in ISRU research and technology development, in the hopes of providing valuable information to the ISRU community at large, spark ideas for future collaborative endeavors, as well as spur interest in utilizing some of the world-class expertise and facilities GRC has to offer.

ISRU↗
NASA NTRSDate not supplied

Early Fire Detection System for Partial and Low Gravity Environments

We present preliminary results on the development of a fire detection system for partial and low gravity environments. A significant challenge is the design of a system with a low false alarm rate. The detection system therefore has to discriminate between combustion particles, cabin, and lunar dust. Aerosol properties are measured and cross referenced to the target detectors at the Gases and Aerosols from Smoldering Polymers (GASP) Laboratory located at the NASA Glenn Research Center. A computational fluid dynamics plume model is also employed to determine the smoke transport properties of the targeted habitats.

Early fire detectioin↗