Results for “Extreme Environments Testing” — Page 30

NASA NTRS2023

Hybrid Thermal Control System for Extreme Thermal Environments

NASA’s return to the moon brings about many challenges, including issues with survival on the Lunar surface. Marshall Space Flight Center (MSFC) has been developing a hybrid thermal control system that can be utilized for various surface assets that must survive in extreme lunar environments. This scalable system is targeted for human-rated systems and utilizes a combination of a- pumped fluid loop (PFL) and a loop heat pipe (LHP) with thermal control valve (TCV). Pumped fluid loops have a long history of use in human rated systems. They can collect large amounts of waste heat and transport it over long distances in rovers, habitats, and other systems. By utilizing a non-toxic working fluid in the habitable volume, the PFL is easily serviceable by the crew and does not pose a risk during any unexpected leaks or failures. The addition of a LHP for the exterior heat transport and rejection adds several benefits to the system for extreme environment survival. The quantity of LHP scan be tailored to optimize heat rejection for different systems and allows for larger adiative surfaces. By utilizing a TCV in combination with the LHP, there can be high heat transfer during the daytime with minimal heat transfer during the night. The TCV passively controls the amount of heat transfer through the LHP based on the environmental temperature. A prototype system has been tested in bench top and thermal vacuum conditions. Results are presented showing the feasibility of the system concept.

Thermal Control↗

NASA NTRS1977

NTS-2 retroreflector array

The NTS-II Laser Retroreflector consists of a honeycomb tray onto which are mounted 44 fused silica cube corners with a 50-millimeter hexagonal entrance pupil and single infrared cube. A thermal shield with a highly reflective outer surface and a black inner surface was incorporated to shroud the assembly protecting it from extreme high temperature exposure thus reducing cube corner thermal distortions to a minimum. A dummy retroreflector, utilizing simulated aluminum cube corners was fabricated and vibration tested to qualification levels to substantiate the integrity of the tray and cube mounting clips. This dummy was further used in the spacecraft spin balance test. The flight Laser Retroreflector was tested to the flight level vibration spectrum to verify that the unit will survive its expected vibration environment. During this test several GFE cube corners exhibited slight crazing at the clip support mounting holes. These cubes were reworked and retested and proved to be satisfactory.

Source record↗

NASA NTRS1979

Fatigue and fracture

The effects of the load/temperature environment of the shuttle on the fatigue life of the body-flap were investigated by conducting real time and accelerated flight-by-flight tests up to 500 flights on coupons containing holes. On the fracture side, much is known about the sensitivity of the tensile strengths of composites to holes and other flaws, predominantly at room temperature. The effects of notches were assessed for graphite/polyimides at the expected temperature extremes of the body-flap: 117K (-250 F) to 589K (600 F). Results indicate that the shuttle temperature extremes may affect fatigue properties HTS/PMR-15. There is no significant effect of temperature on notch-strength. Tensile strengths for specimens with holes and slots are equal.

Illg, W.↗

NASA NTRS1994

Design and performance of the telescope and detector covers on the Extreme Ultraviolet Explorer satellite

Two cover mechanisms were designed and developed for the Extreme Ultraviolet Explorer (EUVE) science payload to keep the EUVE telescope mirrors and detectors sealed from the atmospheric environment until the spacecraft was placed into orbit. There were four telescope front covers and seven motorized detector covers on the EUVE science payload. The EUVE satellite was launched into orbit in June 1992 and all the covers operated successfully after launch. This success can be attributed to high design margins and extensive testing at each level of assembly. This paper described the design of the telescope front covers and the motorized detector covers. This paper also discusses some of the many design considerations and modifications made as performance and reliability problems became apparent from each phase of testing.

Tom, James L.↗

NASA NTRS2024

Dual Glovebox Thermal Vacuum Chamber: Testing Capabilities for Spacesuit Arms and Gloves

The development of Extravehicular Activity (EVA) suits and hand mobility EVA tasks are complex, high risk, and difficult to test in a simulated space environment. During the early assembly of the International Space Station (ISS), the Crew and Thermal Systems Division (CTSD) at NASA Johnson Space Center (JSC) was tasked to design a chamber that could use two Extravehicular Mobility Unit (EMU) arms and gloves in a simulated space environment versus testing with a full suit. The Dual Glovebox (DGB) Chamber was built and served to help develop EVA tools and operations to assist with Return to Flight for the Space Shuttle after the Columbia accident. With the recent development of the Exploration Extravehicular Mobility Unit (xEMU) and new commercial suits through the Extravehicular Activities Services (xEVAS) contract, the DGB can support the need to do suit component testing at thermal extremes and EVA operations without the cost of full suit testing. The DGB can simulate realistic delta pressures, vacuum down to 5x10-4 Torr (0.066 Pa) with roughing and cryogenic pumps, and a wide range of temperatures achieved via a combination of Liquid Nitrogen (LN2), conditioned Gaseous Nitrogen (GN2), Infrared (IR) lamps, and heater cables. Recent developmental work has verified operational status of the chamber and expanded the capabilities of the DGB to include thermal contact testing of suit gloves through two temperature-controlled grab bars. This paper will discuss the history and capabilities of the DGB, and the chamber’s future role in the development of new spacesuit systems.

Extravehicular Activity (EVA)↗

NASA NTRSDate not supplied

Dual Glovebox Thermal Vacuum Chamber: Testing Capabilities for Spacesuit Arms and Gloves

The development of Extravehicular Activity (EVA) suits and hand mobility EVA tasks are complex, high risk, and difficult to test in a simulated space environment. During the early assembly of the International Space Station (ISS), the Crew and Thermal Systems Division (CTSD) at NASA Johnson Space Center (JSC) was tasked to design a chamber that could use two Extravehicular Mobility Unit (EMU) arms and gloves in a simulated space environment versus testing with a full suit. The Dual Glovebox (DGB) Chamber was built and served to help develop EVA tools and operations to assist with Return to Flight for the Space Shuttle after the Columbia accident. With the recent development of the Exploration Extravehicular Mobility Unit (xEMU) and new commercial suits through the Extravehicular Activities Services (xEVAS) contract, the DGB can support the need to do suit component testing at thermal extremes and EVA operations without the cost of full suit testing. The DGB can simulate realistic delta pressures, vacuum down to 5x10-4 Torr (0.066 Pa) with roughing and cryogenic pumps, and a wide range of temperatures achieved via a combination of Liquid Nitrogen (LN2), conditioned Gaseous Nitrogen (GN2), Infrared (IR) lamps, and heater cables. Recent developmental work has verified operational status of the chamber and expanded the capabilities of the DGB to include thermal contact testing of suit gloves through two temperature-controlled grab bars. This paper will discuss the history and capabilities of the DGB, and the chamber’s future role in the development of new spacesuit systems.

Extravehicular Activity (EVA)↗

NASA NTRSDate not supplied

Dual Glovebox Thermal Vacuum Chamber: Testing Capabilities for Spacesuit Arms and Gloves

The development of Extravehicular Activity (EVA) suits and hand mobility EVA tasks are complex, high risk, and difficult to test in a simulated space environment. During the early assembly of the International Space Station (ISS), the Crew and Thermal Systems Division (CTSD) at NASA Johnson Space Center (JSC) was tasked to design a chamber that could use two Extravehicular Mobility Unit (EMU) arms and gloves in a simulated space environment versus testing with a full suit. The Dual Glovebox (DGB) Chamber was built and served to help develop EVA tools and operations to assist with Return to Flight for the Space Shuttle after the Columbia accident. With the recent development of the Exploration Extravehicular Mobility Unit (xEMU) and new commercial suits through the Extravehicular Activities Services (xEVAS) contract, the DGB can support the need to do suit component testing at thermal extremes and EVA operations without the cost of full suit testing. The DGB can simulate realistic delta pressures, vacuum down to 5x10-4 Torr (0.066 Pa) with roughing and cryogenic pumps, and a wide range of temperatures achieved via a combination of Liquid Nitrogen (LN2), conditioned Gaseous Nitrogen (GN2), Infrared (IR) lamps, and heater cables. Recent developmental work has verified operational status of the chamber and expanded the capabilities of the DGB to include thermal contact testing of suit gloves through two temperature-controlled grab bars. This paper will discuss the history and capabilities of the DGB, and the chamber’s future role in the development of new spacesuit systems.

spacesuit arms↗

NASA NTRS2011

Super Dwarf Wheat for Growth in Confined Spaces

USU-Perigee is a dwarf red spring wheat that is a hybrid of a high-yield early tall wheat (USU-Apogee) and a low-yield, extremely short wheat that has poor agronomic characteristics. USU-Perigee was selected for its extremely short height (.0.3 m) and high yield . characteristics that make it suitable for growth in confined spaces in controlled environments. Other desirable characteristics include rapid development and resistance to a leaf-tip necrosis, associated with calcium deficiency, that occurs in other wheat cultivars under rapid-growth conditions (particularly, continuous light). Heads emerge after only 21 days of growth in continuous light at a constant temperature of 25 C. In tests, USU-Perigee was found to outyield other full dwarf (defined as <0.4 m tall) wheat cultivars: The yield advantage at a constant temperature of 23 C was found to be about 30 percent. Originally intended as a candidate food crop to be grown aboard spacecraft on long missions, this cultivar could also be grown in terrestrial growth chambers and could be useful for plant-physiology and -pathology studies.

Bugbee, Bruce↗

NASA NTRSDate not supplied

Dual Glovebox Thermal Vacuum Chamber: Testing Capabilities for Spacesuit Arms and Gloves

The development of Extravehicular Activity (EVA) suits and hand mobility EVA tasks are complex, high risk, and difficult to test in a simulated space environment. During the early assembly of the International Space Station, the Crew and Thermal Systems Division’s Systems Test Branch at NASA JSC was tasked to design a chamber that could use two Extravehicular Mobility Unit (EMU) arms in a simulated space environment versus testing with a full suit. The Dual Glove Box (DGB) Chamber was built and served to help develop EVA tools and operations to assist with Return to Flight for the Space Shuttle after the Columbia accident. With the recent development of the Exploration Extravehicular Mobility Unit (xEMU) and new commercial suits through the Extravehicular Activities Services (xEVAS) contract, the DGB can support the need to do suit component testing at thermal extremes and EVA operations without the cost of full suit testing. The DGB can simulate realistic delta pressures, vacuum down to 10^-5 Torr with roughing and cryogenic pumps, and a wide range of shroud temperatures achieved via a combination of Liquid Nitrogen (LN2), conditioned Gaseous Nitrogen (GN2), and Infrared (IR) lamps. Recent developmental work has verified operational status of the chamber and expanded the capabilities of the DGB to include thermal contact testing of suit gloves through the development of 2 temperature-controlled grab bars. This paper will discuss the history and capabilities of the DGB, and the chamber’s future role in the development of new spacesuit systems.

Kaixin Cui↗

NASA NTRSDate not supplied

Dual Glovebox Thermal Vacuum Chamber: Testing Capabilities for Spacesuit Arms and Gloves

The development of Extravehicular Activity (EVA) suits and hand mobility EVA tasks are complex, high risk, and difficult to test in a simulated space environment. During the early assembly of the International Space Station, the Crew and Thermal Systems Division at NASA JSC was tasked to design a chamber that could use two Extravehicular Mobility Unit (EMU) arms in a simulated space environment versus testing with a full suit. The Dual Glove Box (DGB) Chamber was built and served to help develop EVA tools and operations to assist with Return to Flight for the Space Shuttle after the Columbia accident. With the recent development of the Exploration Extravehicular Mobility Unit (xEMU) and new commercial suits through the Extravehicular Activities Services (xEVAS) contract, the DGB can support the need to do suit component testing at thermal extremes and EVA operations without the cost of full suit testing. The DGB can simulate realistic delta pressures, vacuum down to 10^-5 Torr with roughing and cryogenic pumps, and a wide range of shroud temperatures achieved via a combination of Liquid Nitrogen (LN2), conditioned Gaseous Nitrogen (GN2), Infrared (IR) lamps, and heater plates. Recent developmental work has verified operational status of the chamber and expanded the capabilities of the DGB to include thermal contact testing of suit gloves through the development of 2 temperature-controlled grab bars. This paper will discuss the history and capabilities of the DGB, and the chamber’s future role in the development of new spacesuit systems.

Extravehicular Activity (EVA) suits↗

NASA NTRS1973

Hydrogen environment embrittlement of metals

Hydrogen environment embrittlement refers to metals stressed while exposed to a hydrogen atmosphere. Tested in air, even after exposure to hydrogen under pressure, this effect is not observed on similar specimens. Much high purity hydrogen is prepared by evaporation of liquid hydrogen, and thus has low levels for potential impurities which could otherwise inhibit or poison the absorbent reactions that are involved. High strength steels and nickel-base allows are rated as showing extreme embrittlement; aluminum alloys and the austenitic stainless steels, as well as copper, have negligible susceptibility to this phenomenon. The cracking that occurs appears to be a surface phenomenon, is unlike that of internal hydrogen embrittlement.

Jewett, R. P.↗

NASA NTRS1991

Active member vibration control experiment in a KC-135 reduced gravity environment

An active member vibration control experiment in a KC-135 reduced gravity environment was carried out by the Air Force Flight Dynamics Laboratory and the Jet Propulsion Laboratory. Two active members, consisting of piezoelectric actuators, displacement sensors, and load cells, were incorporated into a 12-meter, 104 kg box-type test structure. The active member control design involved the use of bridge (compound) feedback concept, in which the collocated force and velocity signals are feedback locally. An impact-type test was designed to accommodate the extremely short duration of the reduced gravity testing window in each parabolic flight. The moving block analysis technique was used to estimate the modal frequencies and dampings from the free-decay responses. A broadband damping performance was demonstrated up to the ninth mode of 40 Hz. The best damping performance achieved in the flight test was about 5 percent in the fourth mode of the test structure.

Lawrence, C. R.↗

NASA NTRS2007

Materials Safety - Not just Flammability and Toxic Offgassing

For many years, the safety community has focused on a limited subset of materials and processes requirements as key to safety: Materials flammability, Toxic offgassing, Propellant compatibility, Oxygen compatibility, and Stress-corrosion cracking. All these items are important, but the exclusive focus on these items neglects many other items that are equally important to materials safety. Examples include (but are not limited to): 1. Materials process control -- proper qualification and execution of manufacturing processes such as structural adhesive bonding, welding, and forging are crucial to materials safety. Limitation of discussions on materials process control to an arbitrary subset of processes, known as "critical processes" is a mistake, because any process where the quality of the product cannot be verified by inspection can potentially result in unsafe hardware 2 Materials structural design allowables -- development of valid design allowables when none exist in the literature requires extensive testing of multiple lots of materials and is extremely expensive. But, without valid allowables, structural analysis cannot verify structural safety 3. Corrosion control -- All forms of corrosion, not just stress corrosion, can affect structural integrity of hardware 4. Contamination control during ground processing -- contamination control is critical to manufacturing processes such as adhesive bonding and also to elimination foreign objects and debris (FOD) that are hazardous to the crew of manned spacecraft in microgravity environments. 5. Fasteners -- Fastener design, the use of verifiable secondary locking features, and proper verification of fastener torque are essential for proper structural performance This presentation discusses some of these key factors and the importance of considering them in ensuring the safety of space hardware.

Pedley, Michael D.↗

NASA NTRS2010

Testing and Results of Human Metabolic Simulation Utilizing Ultrasonic Nebulizer Technology for Water Vapor Generation

Life support technology must be evaluated thoroughly before ever being implemented into a functioning design. A major concern during that evaluation is safety. The ability to mimic human metabolic loads allows test engineers to evaluate the effectiveness of new technologies without risking injury to any actual humans. The main function of most life support technologies is the removal of carbon dioxide (CO2) and water (H2O) vapor. As such any good human metabolic simulator (HMS) will mimic the human body s ability to produce these items. Introducing CO2 into a test chamber is a very straightforward process with few unknowns so the focus of this particular new HMS design was on the much more complicated process of introducing known quantities of H2O vapor on command. Past iterations of the HMS have utilized steam which is very hard to keep in vapor phase while transporting and injecting into a test chamber. Also steam adds large quantities of heat to any test chamber, well beyond what an actual human does. For the new HMS an alternative approach to water vapor generation was designed utilizing ultrasonic nebulizers as a method for creating water vapor. Ultrasonic technology allows water to be vibrated into extremely tiny pieces (2-5 microns) and evaporate without requiring additional heating. Doing this process inside the test chamber itself allows H2O vapor generation without the unwanted heat and the challenging process of transporting water vapor. This paper presents the design details as well as results of all initial and final acceptance system testing. Testing of the system was performed at a range of known human metabolic rates in both sea-level and reduced pressure environments. This multitude of test points fully defines the systems capabilities as they relate to actual environmental systems testing.

Stubbe, Matthew↗

NASA NTRSDate not supplied

Electrospun Silica Nanofibers as Passive Thermal Control Materials for the Extreme Environment of Low Earth Orbit

Effective thermal management is crucial for maintaining spacecraft and onboard systems at optimal temperatures, ensuring their longevity in space missions. Passive thermal management is particularly promising due to its lower power consumption compared to active systems. This study focuses on developing materials with low solar absorptance and large thermal emittance to facilitate self-cooling under the harsh thermal conditions of space. We employ electrospinning, a nano/micro-manufacturing technique, to create a lightweight, fibrous thermal control material from silica (SiO 2 ). Using scanning electron microscopy (SEM), we examine the nanoporous structure of the electrospun material. Its optical properties, including reflectance, transmittance, and absorptance across ultraviolet, visible, and infrared wavelengths, are assessed using spectrometers interfaced with integrating spheres. To test durability in space, we conduct high temperature endurance and ultraviolet resistance tests to observe changes in optical properties of the materials and evaluate their performance in low Earth orbit (LEO). We also compare the material's solar reflectance and thermal emittance to existing spacecraft materials. The findings suggest that electrospun silica nanofibers presents a new paradigm for passive thermal control in space applications.

thermal emittance↗

NASA NTRSDate not supplied

Thin Film Physical Sensors for High Temperature Applications

For the advanced engines in the future, knowledge of the physical parameters of aerospace components is necessary on the test stand and in flight. NASA GRC is leveraging expertise in thin films and high temperature materials to measure hot section gas and surface temperature, heat flux and static and dynamic strain. The current challenges of instrumentation technology are to further develop systems packaging and component testing of specialized sensors, further develop instrumentation techniques on complex surfaces, improve sensor durability, and to address needs for extreme temperature applications. Applications of thin film ceramic sensors as replacement for noble metals are being investigated. Technologies demonstrated in aeronautics and space applications are outlined.

thin films↗

NASA NTRS2007

NTREES Testing and Operations Status

Nuclear Thermal Rockets or NTR's have been suggested as a propulsion system option for vehicles traveling to the moon or Mars. These engines are capable of providing high thrust at specific impulses at least twice that of today's best chemical engines. The performance constraints on these engines are mainly the result of temperature limitations on the fuel coupled with a limited ability to withstand chemical attack by the hot hydrogen propellant. To operate at maximum efficiency, fuel forms are desired which can withstand the extremely hot, hostile environment characteristic of NTR operation for at least several hours. The simulation of such an environment would require an experimental device which could simultaneously approximate the power, flow, and temperature conditions which a nuclear fuel element (or partial element) would encounter during NTR operation. Such a simulation would allow detailed studies of the fuel behavior and hydrogen flow characteristics under reactor like conditions to be performed. Currently, the construction of such a simulator has been completed at the Marshall Space Flight Center, and will be used in the future to evaluate a wide variety of fuel element designs and the materials of which they are fabricated. This present work addresses the operational status of the Nuclear Thermal Rocket Element Environmental Simulator or NTREES and some of the design considerations which were considered prior to and during its construction.

Emrich, Bill↗

NASA NTRS2011

Gripping Mechanisms for Microgravity and Extreme Terrain and Vertical Climbing Micro Ground Vehicle

Asteroids and comets may provide insight into the origins of our solar system and the precursors to life on our planet. Near Earth objects offer an accessible target of opportunity, but are small and lack the gravity necessary for conventional wheeled travel. Therefore, it is necessary to develop alternative methods for maneuvering in these environments. This project researched and developed a method for gripping rock surfaces. Work has been completed on the design and prototyping of several possible hooked gripping mechanisms. Future work includes quantitative testing, downselection to a final design, and attachment to the robotic platform, Lemur IIb. A second project focuses on the development of a 100g, crash-proof robot capable of climbing vertical surfaces using a novel silicone adhesive. Capable of carrying video/audio payloads the robot may serve as a surveillance tool for the Department of Defense or as a method of pre-flight spacecraft inspections. A specialized track was developed to provide the specific loading conditions necessary for proper engagement of the adhesive. Both of these projects rely heavily on the shape deposition manufacturing process, being researched at JPL, and 3D printing.

robotic locomotion↗