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All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Lunar Development & Test Facility, JSC B351

In anticipation of extended operations on the lunar sur-face, JSC Building B351 has been prepared to meet test needs to mature technologies that extract resources from lunar regolith, handle lunar regolith or must perform in a dusty lunar environment. Domains such as In-Situ Re-source Utilization (ISRU), dust mitigation, power generation and distribution, robotics and surface tools will all require testing with lunar regolith/simulants to demonstrate flight readiness. The Lunar Development and Test Facility (LDTF) houses environmental test capabilities, including lunar simulants, geared toward advancing Technical Readiness Level (TRL) of these lunar surface technologies. Seen as an agency need to enable and demonstrate new technologies, a portion of the facility capability was developed under the “Dirty Lunar Surface Simulation “project in FY2020, funded by the NASA Game Changing Development program. Some current uses include testing of an oxygen extraction from lunar regolith test, a spacesuit cleaning tool evaluation, and a study to measure dust effects on space radiators (thermal management).

Michael Reddington↗
NASA NTRSDate not supplied

Smooth Particle Hydrodynamic Code Predictions for Meteoroid Damage to Thermal Protection Systems Shielded By Composite Structures

Interplanetary spacecraft are exposed to meteoroid fluxes with characteristics far exceeding the physical simulation capabilities of test facilities for predicting the likelihood that a meteoroid will penetrate a spacecraft’s critical systems. Accurate risk predictions are crucial to ensuring that important interplanetary missions, such as sample returns, can survive years of exposure to the meteoroid environment and safely reenter the Earth’s atmosphere with their scientific cargo. In this paper, we summarize a series of meteoroid impact damage computational simulations into two types of spacecraft composite protective structures using the Smooth Particle Hydrodynamics Code. We consider the effects of both meteoric materials and non-meteoric materials on a shielded forebody thermal protection system (TPS) for an extreme entry environment and on an unshielded aftbody TPS that is similar to the material covering the space shuttle’s external tank.

Brooke Corbett↗
NASA NTRS2011

Fusion Propulsion Z-Pinch Engine Concept

Fusion-based nuclear propulsion has the potential to enable fast interplanetary transportation. Due to the great distances between the planets of our solar system and the harmful radiation environment of interplanetary space, high specific impulse (Isp) propulsion in vehicles with high payload mass fractions must be developed to provide practical and safe vehicles for human spaceflight missions. The Z-Pinch dense plasma focus method is a Magneto-Inertial Fusion (MIF) approach that may potentially lead to a small, low cost fusion reactor/engine assembly1. Recent advancements in experimental and theoretical understanding of this concept suggest favorable scaling of fusion power output yield 2. The magnetic field resulting from the large current compresses the plasma to fusion conditions, and this process can be pulsed over short timescales (10(exp -6 sec). This type of plasma formation is widely used in the field of Nuclear Weapons Effects testing in the defense industry, as well as in fusion energy research. A Decade Module 2 (DM2), approx.500 KJ pulsed-power is coming to the RSA Aerophysics Lab managed by UAHuntsville in January, 2012. A Z-Pinch propulsion concept was designed for a vehicle based on a previous fusion vehicle study called "Human Outer Planet Exploration" (HOPE), which used Magnetized Target Fusion (MTF) 3 propulsion. The reference mission is the transport of crew and cargo to Mars and back, with a reusable vehicle.

Miernik, J.↗
NASA NTRS2013

Behavior Prediction Tools Strengthen Nanoelectronics

Several years ago, NASA started making plans to send robots to explore the deep, dark craters on the Moon. As part of these plans, NASA needed modeling tools to help engineer unique electronics to withstand extremely cold temperatures. According to Jonathan Pellish, a flight systems test engineer at Goddard Space Flight Center, "An instrument sitting in a shadowed crater on one of the Moon s poles would hover around 43 K", that is, 43 kelvin, equivalent to -382 F. Such frigid temperatures are one of the main factors that make the extreme space environments encountered on the Moon and elsewhere so extreme. Radiation is another main concern. "Radiation is always present in the space environment," says Pellish. "Small to moderate solar energetic particle events happen regularly and extreme events happen less than a handful of times throughout the 7 active years of the 11-year solar cycle." Radiation can corrupt data, propagate to other systems, require component power cycling, and cause a host of other harmful effects. In order to explore places like the Moon, Jupiter, Saturn, Venus, and Mars, NASA must use electronic communication devices like transmitters and receivers and data collection devices like infrared cameras that can resist the effects of extreme temperature and radiation; otherwise, the electronics would not be reliable for the duration of the mission.

Source record↗
NASA NTRS2017

Simulation Based Studies of Low Latency Teleoperations for NASA Exploration Missions

Human exploration of Mars will involve both crewed and robotic systems. Many mission concepts involve the deployment and assembly of mission support assets prior to crew arrival on the surface. Some of these deployment and assembly activities will be performed autonomously while others will be performed using teleoperations. However, significant communications latencies between the Earth and Mars make teleoperations challenging. Alternatively, low latency teleoperations are possible from locations in Mars orbit like Mars' moons Phobos and Deimos. To explore these latency opportunities, NASA is conducting a series of studies to investigate the effects of latency on telerobotic deployment and assembly activities. These studies are being conducted in laboratory environments at NASA's Johnson Space Center (JSC), the Human Exploration Research Analog (HERA) at JSC and the NASA Extreme Environment Mission Operations (NEEMO) underwater habitat off the coast of Florida. The studies involve two human-in-the-loop interactive simulations developed by the NASA Exploration Systems Simulations (NExSyS) team at JSC. The first simulation investigates manipulation related activities while the second simulation investigates mobility related activities. The first simulation provides a simple real-time operator interface with displays and controls for a simulated 6 degree of freedom end effector. The initial version of the simulation uses a simple control mode to decouple the robotic kinematic constraints and a communications delay to model latency effects. This provides the basis for early testing with more detailed manipulation simulations planned for the future. Subjects are tested using five operating latencies that represent teleoperation conditions from local surface operations to orbital operations at Phobos, Deimos and ultimately high Martian orbit. Subject performance is measured and correlated with three distance-to-target zones of interest. Each zone represents a target distance ranging from beyond 10m in Zone 1, through 1 cm to contact in Zone 5 with a step size factor of 10. Collected data consists of both objective simulation data (time, distance, hand controller inputs, velocity) and subjective questionnaire data. The second simulation provides a simple real-time operator interface with displays and control of a simulated surface rover. The rover traverses a synthetic Mars-like terrain and must be maneuvered to avoid obstacles while progressing to its destination. Like the manipulator simulation, subjects are tested using five operating latencies that represent teleoperation conditions from local surface operations to orbital operations at Phobos, Deimos and ultimately high Martian orbit. The rover is also operated at three different traverse speeds to assess the correlation between latency and speed. Collected data consisted of both objective simulation data (time, distance, hand controller inputs, braking) and subjective questionnaire data. These studies are exploring relationships between task complexity, operating speeds, operator efficiencies, and communications latencies for low latency teleoperations in support of human planetary exploration. This paper presents early results from these studies along with the current observations and conclusions. These and planned future studies will help to inform NASA on the potential for low latency teleoperations to support human exploration of Mars and inform the design of robotic systems and exploration missions.

Gernhardt, Michael L.↗
NASA NTRS2020

Pterodactyl: Control System Demonstrator Development for Integrated Control Design of a Mechanically Deployed Entry Vehicle

The NASA-funded Pterodactyl project is a design, test, and build capability to (i) advance the current state of the art for Deployable Entry Vehicle (DEV) guidance and control (G&C), and (ii) determine the feasibility of control system integration for various entry vehicle types including those without aeroshells. This capability is currently being used to develop control systems for one such unconventional entry vehicle, the Lifting Nano-ADEPT (LNA) vehicle. ADEPT offers the possibility of integrating control systems directly onto the mechanically deployed structure and building hardware demonstrators will help assess integration and design challenges. Control systems based on aerodynamic control surfaces, mass movement, and reaction control systems (RCS) are currently being investigated for a down-select to the most suitable control architecture for the LNA.To that effect, in this submission, we detail the efforts of the Pterodactyl project to develop a series of hardware demonstrators for the different LNA control systems. Rapid prototypes, for a set of quarter- model or eighth-model vehicle segments, will be developed for all three architectures to validate mechanical design assumptions, and hardware-in-the-loop (HIWL) control approaches. A ground test control system demonstrator will be designed and built after the trade study is complete. The industrial-grade demonstrator will be designed so that it can be incorporated into a HWIL simulation to further validate the findings of the initial trade study. The HWIL simulation will leverage the iPAS environment developed at NASA's Johnson Space Center which facilitates integration testing to support technology maturation and risk reduction, necessary elements for the hardware demonstration development detailed in this paper.

Margolis, Benjamin W.↗
NASA NTRS1987

Space station integrated wall design and penetration damage control

A methodology was developed to allow a designer to optimize the pressure wall, insulation, and meteoroid/debris shield system of a manned spacecraft for a given spacecraft configuration and threat environment. The threat environment consists of meteoroids and orbital debris, as specified for an arbitrary orbit and expected lifetime. An overall probability of no penetration is calculated, as well as contours of equal threat that take into account spacecraft geometry and orientation. Techniques, tools, and procedures for repairing an impacted and penetrated pressure wall were developed and tested. These techniques are applied from the spacecraft interior and account for the possibility of performing the repair in a vacuum. Hypervelocity impact testing was conducted to: (1) develop and refine appropriate penetration functions, and (2) determine the internal effects of a penetration on personnel and equipment.

Coronado, A. R.↗
NASA NTRS2001

Effect of Slow External Flow on Flame Spreading over Solid Material: Opposed Spreading over Polyethylene Wire Insulation

The effect of slow external flow on solid combustion is very important from the view of fire safety in space because the solid material in spacecraft is generally exposed to the low air flow for ventilation. Further, the effect of low external flow on fuel combustion is generally fundamental information for industrial combustion system, such as gas turbine, boiler incinerator and so on. However, it is difficult to study the effect of low external flow on solid combustion in normal gravity, because the buoyancy-induced flow strongly disturbs the flow field, especially for low flow velocity. In this research therefore, the effect of slow external flow on opposed flame spreading over polyethylene (PE) wire insulation have been investigated in microgravity. The microgravity environment was provided by Japan Microgravity Center (JAMIC) in Japan and KC-135 at NASA GRC. The tested flow velocity range is 0-30cm/s with different oxygen concentration and inert gas component.

Fujita, O.↗
NASA NTRS2007

Characterization of a Prototype Radio Frequency Space Environment Path Emulator for Evaluating Spacecraft Ranging Hardware

The Formation Flying Testbed (FFTB) at the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) provides a hardware-in-the-loop test environment for formation navigation and control. The facility is evolving as a modular, hybrid, dynamic simulation facility for end-to-end guidance, navigation and control (GN&C) design and analysis of formation flying spacecraft. The core capabilities of the FFTB, as a platform for testing critical hardware and software algorithms in-the-loop, have expanded to include S-band Radio Frequency (RF) modems for interspacecraft communication and ranging. To enable realistic simulations that require RF ranging sensors for relative navigation, a mechanism is needed to buffer the RF signals exchanged between spacecraft that accurately emulates the dynamic environment through which the RF signals travel, including the effects of the medium, moving platforms, and radiated power. The Path Emulator for Radio Frequency Signals (PERFS), currently under development at NASA GSFC, provides this capability. The function and performance of a prototype device are presented.

Mitchell, Jason W.↗
NASA NTRS2007

Aerogel Insulation Applications for Liquid Hydrogen Launch Vehicle Tanks

Aerogel based insulation systems for ambient pressure environments were developed for liquid hydrogen (LH2) tank applications. Solutions to thermal insulation problems were demonstrated for the Space Shuttle External Tank (ET) through extensive testing at the Cryogenics Test Laboratory. Demonstration testing was performed using a 1/10th scale ET LH2 intertank unit and liquid helium as the coolant to provide the 20 K cold boundary temperature. Cryopumping tests in the range of 20K were performed using both constant mass and constant pressure methods. Long-duration tests (up to 10 hours) showed that the nitrogen mass taken up inside the intertank is reduced by a factor of nearly three for the aerogel insulated case as compared to the un-insulated (bare metal flight configuration) case. Test results including thermal stabilization, heat transfer effectiveness, and cryopumping confirm that the aerogel system eliminates free liquid nitrogen within the intertank. Physisorption (or adsorption) of liquid nitrogen within the fine pore structure of aerogel materials was also investigated. Results of a mass uptake method show that the sorption ratio (liquid nitrogen to aerogel beads) is about 62 percent by volume. A novel liquid nitrogen production method of testing the liquid nitrogen physical adsorption capacity of aerogel beads was also performed to more closely approximate the actual launch vehicle cooldown and thermal stabilization effects within the aerogel material. The extraordinary insulating effectiveness of the aerogel material shows that cryopumping is not an open-cell mass transport issue but is strictly driven by thermal communication between warm and cold surfaces. The new aerogel insulation technology is useful to solve heat transfer problem areas and to augment existing thermal protection systems on launch vehicles. Examples are given and potential benefits for producing launch systems that are more reliable, robust, reusable, and efficient are outlined.

Fesmire, J. E.↗
NASA NTRS2011

Ares I Scale Model Acoustic Tests Instrumentation for Acoustic and Pressure Measurements

The Ares I Scale Model Acoustic Test (ASMAT) was a development test performed at the Marshall Space Flight Center (MSFC) East Test Area (ETA) Test Stand 116. The test article included a 5% scale Ares I vehicle model and tower mounted on the Mobile Launcher. Acoustic and pressure data were measured by approximately 200 instruments located throughout the test article. There were four primary ASMAT instrument suites: ignition overpressure (IOP), lift-off acoustics (LOA), ground acoustics (GA), and spatial correlation (SC). Each instrumentation suite incorporated different sensor models which were selected based upon measurement requirements. These requirements included the type of measurement, exposure to the environment, instrumentation check-outs and data acquisition. The sensors were attached to the test article using different mounts and brackets dependent upon the location of the sensor. This presentation addresses the observed effect of the sensors and mounts on the acoustic and pressure measurements.

Vargas, Magda B.↗
NASA NTRS2016

NASA's Contributions to Controlled Environment Agriculture

It may come as a surprise, but NASA has been a long-standing sponsor of controlled environment agriculture (CEA) research. This is based on the potential for using plants (crops) for life support systems in space. Through photosynthesis, crops could produce food and oxygen for humans, while removing CO2. In addition, plant transpiration could help purify waste water. NASAs interest in bioregenerative life support dates back to the late 1950s. At that time, much of the testing focused on algae, but over the years moved toward higher plants as CEA techniques improved. Throughout the 1980s and 90s, extensive testing was carried out at different universities to gather horticultural data for a range of crops, including wheat, soybean, lettuce, potato, sweet potato, cowpea, rice and more. These studies examined different electric light sources, mineral nutrition, recirculating hydroponics, effects of CO2, temperature, photosynthetic photon flux (PPF), and photoperiod on the crops, and identified cultivars that would be useful for space. Findings from these studies were then used to conduct large scale (20 sq m), closed atmosphere tests at Kennedy Space Center, and later at NASA Johnson Space Center, where plant growth chambers were linked to human habitats. Results showed that with high light input and careful horticultural management, about 20-25 sq m of crops under continuous cultivation could produce the O2 for one person, and about 40-50 sq m could produce enough dietary calories. The ability to sustain these production levels and accurately assess system costs and failures needs further study. In all likelihood, the use of plants for life support will evolve, where for early missions like the International Space Station, crops will be grown in small chambers to provide supplemental fresh foods. As mission durations and distances increase, the systems could expand to assume more of the life support burden. But the constraints of space travel require that these approaches be efficient in terms of mass, volume, and energy, which are similar to challenges facing terrestrial CEA, such as vertical agriculture systems.

Bioregenerative↗
NASA NTRS2019

Sub-Picometer Dynamic Measurements of a Diffuse Surface

Future space observatory missions are forecasting the need for sensing and controlling wave front error and system alignment stability to picometer scale. Picometer stability performance demands precision knowledge of the mirror and metering structure materials to the same degree. A high-speed electronic speckle pattern interferometer was designed and built to demonstrate measurements of both static and dynamic responses of picometer amplitudes in materials of diffuse surface subjected to very low energy disturbances. This paper describes the details of a test to impart a dynamic disturbance of picometer scale and measure the response of a composite material.The results of the test are also reported and show conclusively that sub-picometer scale effects can be accurately measured in an open test environment outside a vacuum chamber.

Saif, Babak↗
NASA NTRSDate not supplied

Environmental and Polarization Characterizations of E-Beam Plasma-Based AlF 3 -Passivated Aluminum Mirrors for Astronomical Telescopes

Astronomical space telescopes to study astrophysical phenomena from the far ultraviolet (FUV) to the near infrared (NIR) will require mirror coatings with high reflectance over this entire spectral region. While coatings for the optical and NIR part of the spectrum are fairly well developed with proven performance, the FUV range has presented significant challenges, particularly below 120nm. Recent developments in electron-beam (e-Beam) generated plasma treatment in a SF 6 environments has enabled the effective passivation of aluminum (Al) coatings for applications in the FUV, by native oxide removal and the formation of a AlF 3 passivation layer which could be tuned to any desired AlF 3 thickness. These results have been produced through a collaboration between the Goddard Space Flight Center (GSFC) and the Naval Research Laboratory (NRL). The passivation experiments have been carried out using the Large Area Plasma Processing System (LAPPS) at NRL using bare aluminum samples and provided by the coating group at GSFC. This novel procedure has demonstrated improved Al mirrors with state-of-the-art FUV reflectivity (e.g. R=91% at 121.6nm). In this paper, we will be reporting on environmental testing, micro-roughness, as well as polarization studies of these E-beam treated samples. These characterizations are being done in order to advance the Technology Readiness Level (TRL) for these Al+AlF 3 mirror coatings produced at LAPPS. The ultimate goal is to demonstrate the promise of using this coating technology to deliver reflectance performance plus stability and uniformity over a large area for a future IR/O/UV space telescope observatory.

FUV reflectance↗
DOE OSTI2020

Experimental apparatus and methodology to test and quantify thermal performance of micro and macro-encapsulated phase change materials in building envelope applications

Thermal energy storage (TES) is used as a viable technology to shift peak electricity demand caused by the space cooling requirements in buildings. Passive TES is implemented in building envelope via micro and macroencapsulation methods. This study describes the use of a state-of-the-art laboratory to test different PCM inclusions in simplified building walls. A microencapsulated PCM and two macroencapsulated PCMs are tested in a controlled environment to gather data for validation purposes of PCM modelling algorithms in building energy modelling programs. Data indicates that the chamber environment and the heating and cooling system can conduct full-cycle tests of wall panels with PCM inclusions. This study also generates data from parallel tests on 4 wall panels which can be used in building energy modelling programs to validate the PCM modelling algorithms. The cyclic tests also capture the thermal effects of PCMs and complex PCM behaviors like sub-cooling in PCM hydrate-salts.

25 ENERGY STORAGE↗
NASA NTRS1972

Survey of materials for hydrazine propulsion systems in multicycle extended life applications

An assessment is presented of materials compatibility data for hydrazine monopropellant propulsion systems applicable to the Space Shuttle vehicle missions. Materials were evaluated for application over a 10-yr/100-mission operational lifetime with minimum refurbishment. A general materials compatibility rating for a broad range of materials and several propellants based primarily on static liquid propellant immersion testing and an in-depth evaluation of hydrazine decomposition as a function of purity, temperature, material, surface conditions, etc., are presented. The most promising polymeric material candidates for propellant diaphragms and seals appear to have little effect on increasing hydrazine decomposition rates, but the materials themselves do undergo changes in physical properties which can affect their 10-yr performance in multicycle applications. The available data on these physical properties of elastomeric materials as affected by exposure to hydrazine or related environments are presented.

Coulbert, C. D.↗
NASA NTRS1997

Modular Rocket Engine Control Software (MRECS)

The Modular Rocket Engine Control Software (MRECS) Program is a technology demonstration effort designed to advance the state-of-the-art in launch vehicle propulsion systems. Its emphasis is on developing and demonstrating a modular software architecture for a generic, advanced engine control system that will result in lower software maintenance (operations) costs. It effectively accommodates software requirements changes that occur due to hardware. technology upgrades and engine development testing. Ground rules directed by MSFC were to optimize modularity and implement the software in the Ada programming language. MRECS system software and the software development environment utilize Commercial-Off-the-Shelf (COTS) products. This paper presents the objectives and benefits of the program. The software architecture, design, and development environment are described. MRECS tasks are defined and timing relationships given. Major accomplishment are listed. MRECS offers benefits to a wide variety of advanced technology programs in the areas of modular software, architecture, reuse software, and reduced software reverification time related to software changes. Currently, the program is focused on supporting MSFC in accomplishing a Space Shuttle Main Engine (SSME) hot-fire test at Stennis Space Center and the Low Cost Boost Technology (LCBT) Program.

Tarrant, Charlie↗