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NASA NTRS2010

Risk-Informed Decision Making: Application to Technology Development Alternative Selection

NASA NPR 8000.4A, Agency Risk Management Procedural Requirements, defines risk management in terms of two complementary processes: Risk-informed Decision Making (RIDM) and Continuous Risk Management (CRM). The RIDM process is used to inform decision making by emphasizing proper use of risk analysis to make decisions that impact all mission execution domains (e.g., safety, technical, cost, and schedule) for program/projects and mission support organizations. The RIDM process supports the selection of an alternative prior to program commitment. The CRM process is used to manage risk associated with the implementation of the selected alternative. The two processes work together to foster proactive risk management at NASA. The Office of Safety and Mission Assurance at NASA Headquarters has developed a technical handbook to provide guidance for implementing the RIDM process in the context of NASA risk management and systems engineering. This paper summarizes the key concepts and procedures of the RIDM process as presented in the handbook, and also illustrates how the RIDM process can be applied to the selection of technology investments as NASA's new technology development programs are initiated.

Dezfuli, Homayoon↗
NASA NTRS2009

The OMPS Limb Profiler Instrument: An Alternative Data Analysis and Retrieval Algorithm

The upcoming Ozone Mapper and Profiler Suite (OMPS), which will be launched on the NPOESS Preparatory Project (NPP) platform in early 2011, will continue monitoring the global distribution of the Earth's middle atmosphere ozone and aerosol. OMPS is composed of three instruments, namely the Total Column Mapper (heritage: TOMS, OMI), the Nadir Profiler (heritage: SBUV) and the Limb Profiler (heritage: SOLSE/LORE, OSIRIS, SCIAMACHY, SAGE III). The ultimate goal of the mission is to better understand and quantify the rate of stratospheric ozone recovery. The focus of the paper will be on the Limb Profiler (LP) instrument. The LP instrument will measure the Earth fs limb radiance (which is due to the scattering of solar photons by air molecules, aerosol and Earth surface) in the ultra-violet (UV), visible and near infrared, from 285 to 1000 nm. The LP simultaneously images the whole vertical extent of the Earth's limb through three vertical slits, each covering a vertical tangent height range of 100 km and each horizontally spaced by 250 km in the cross-track direction. The focal plane of the LP spectrometer is a two ]dimensional CCD array comprised of 340 x 740 pixels. Several data analysis tools are presently being constructed and tested to retrieve ozone and aerosol vertical distribution from limb radiance measurements. The primary NASA algorithm is based on earlier algorithms developed for the SOLSE/LORE and SAGE III limb scatter missions. The paper will describe an alternative algorithm which will retrieve ozone density and aerosol extinction directly from radiance data collected on individual CCD pixels. This alternative method uses an optimal estimation approach to retrieve ozone and aerosol in the 10-60 km range from the information contained within an ensemble of about 50000 down-linked pixels. Tangent height registration is performed using the Rayleigh Scattering Attitude Sensor (RSAS) technique applied to columns of pixels in the 340-360 nm range. Cloud height is determined by analyzing the radiance first derivative along pixel columns at longer wavelengths. Wavelength registration is performed using rows of pixels and identifying Fraunhofer solar lines within the measured spectra. Special attention is given to stray-light decontamination and modeling of the measured finite spectral/spatial line shape functions.

Rault, Didier F.↗
NASA NTRS2000

Purification of Carbon Nanotubes: Alternative Methods

Traditional carbon nanotube purification process involves nitric acid refluxing and cross flow filtration using surfactant TritonX. This is believed to result in damage to nanotubes and surfactant residue on nanotube surface. Alternative purification procedures involving solvent extraction, thermal zone refining and nitric acid refiuxing are used in the current study. The effect of duration and type of solvent to dissolve impurities including fullerenes and P ACs (polyaromatic compounds) are monitored by nuclear magnetic reasonance, high performance liquid chromatography, and thermogravimetric analysis. Thermal zone refining yielded sample areas rich in nanotubes as seen by scanning electric microscopy. Refluxing in boiling nitric acid seem to improve the nanotube content. Different procedural steps are needed to purify samples produced by laser process compared to arc process. These alternative methods of nanotube purification will be presented along with results from supporting analytical techniques.

Files, Bradley↗
NASA NTRS2011

NASA TEERM Hexavalent Chrome Alternatives Projects

This slide presentation reviews the NASA project to select an alternative to hexavalent chrome in the aerospace industry. Included is a recent historic testing and research that the Agency has performed on (1) the external tank, (2) the shuttle orbiter, (3) the Shuttle Rocket Booster, and (4) the Space Shuttle Main Engine. Other related Technology Evaluation for Environmental Risk Mitigation (TEERM) projects are reviewed. The Phase I process of the project performed testing of alternatives the results are shown in a chart for different coating systems. International collaboration was also reviewed. Phase II involves further testing of pretreatment and primers for 6 and 12 months of exposure to conditions at Launch Pad and the beach. Further test were performed to characterize the life cycle corrosion of the space vehicles. A new task is described as a joint project with the Department of Defense to identify a Hex Chrome Free Coatings for Electronics.

Kessel, Kurt↗
NASA NTRS2005

Field Evaluations Test Plan for Validation of Alternative Low-Emission Surface Preparation/Depainting Technologies for Structural Steel

Headquarters National Aeronautics and Space Administration (NASA) chartered the Acquisition Pollution Prevention (AP2) Office to coordinate agency activities affecting pollution prevention issues identified during system and component acquisition and sustainment processes. The primary objectives of the AP2 Office are to: (1) Reduce or eliminate the use of hazardous materials (HazMats) or hazardous processes at manufacturing, remanufacturing, and sustainment locations. (2) Avoid duplication of effort in actions required to reduce or eliminate HazMats through joint center cooperation and technology sharing. To achieve a substrate condition suitable for the application of a coating system, both new and old (in-situ) substrates must undergo some type of surface preparation and/or depainting operation to ensure adhesion of the new coating system. The level of cleanliness or anchor profile desired is typically a function of the type of coating to be applied and the specification being adhered to. In high performance environments, cleanliness and surface profile requirements for carbon steel (the dominant substrate for facilities, structures and equipment) dictates the use of abrasive media. Many of the abrasive media currently used across NASA and Air Force Space Command (AFSPC) installations generate large quantities of fugitive particulate emissions and waste. The high quantities of airborne dust and waste generated from these operations pose significant environmental concern. Efforts to contain emissions and the reduce quantity of waste generated have significant implications on project cost; this is often a deterrent to engaging in maintenance activities. In response to recent technological developments and NASA's and AFSPC's need to undertake environmentally conscious corrosion prevention projects, a review of the industry needs to be undertaken to evaluate surface preparation technologies (materials and processes) for embrace. This project will identify, evaluate and approve alternative surface preparation technologies for use at NASA and AFSPC installations. Materials and processes will be evaluated with the goal of selecting those processes that will improve corrosion protection at critical systems, facilitate easier maintenance activity, extend maintenance cycles, eliminate flight hardware contamination and reduce the amount of hazardous waste generated. This Field Evaluations Test Plan defines the field evaluation and testing requirements for validating alternative surface preparation/depainting technologies and supplements the JTP. The field evaluations will be performed at Stennis Space Center, Mississippi, under the oversight of the Project Engineer. Additional field evaluations may be performed at other NASA centers or AFSPC facilities.

Lewis, Pattie↗
NASA NTRS2011

An Alternative Approach to Human Servicing of Manned Earth Orbiting Spacecraft

As manned spacecraft have grown larger and more complex, they have come to rely on spacewalks or Extravehicular Activities (EVA) for both mission success and crew safety. Typically these spacecraft maintain all of the hardware and trained personnel needed to perform an EVA on-board at all times. Maintaining this capability requires volume and up-mass for storage of EVA hardware, crew time for ground and on-orbit training, and on-orbit maintenance of EVA hardware . This paper proposes an alternative methodology to utilize launch-on-need hardware and crew to provide EVA capability for space stations in Earth orbit after assembly complete, in the same way that most people would call a repairman to fix something at their home. This approach would not only reduce ground training requirements and save Intravehicular Activity (IVA) crew time in the form of EVA hardware maintenance and on-orbit training, but would also lead to more efficient EVAs because they would be performed by specialists with detailed knowledge and training stemming from their direct involvement in the development of the EVA. The on-orbit crew would then be available to focus on the immediate response to the failure as well as the day-to-day operations of the spacecraft and payloads. This paper will look at how current ISS unplanned EVAs are conducted, including the time required for preparation, and offer alternatives for future spacecraft utilizing lessons learned from ISS. As this methodology relies entirely on the on-time and on-need launch of spacecraft, any space station that utilized this approach would need a robust transportation system including more than one launch vehicle capable of carrying crew. In addition the fault tolerance of the space station would be an important consideration in how much time was available for EVA preparation after the failure. Each future program would have to weigh the risk of on-time launch against the increase in available crew time for the main objective of the spacecraft.

Mularski, John↗
NASA NTRS2004

Alternative Attitude Commanding and Control for Precise Spacecraft Landing

A report proposes an alternative method of control for precision landing on a remote planet. In the traditional method, the attitude of a spacecraft is required to track a commanded translational acceleration vector, which is generated at each time step by solving a two-point boundary value problem. No requirement of continuity is imposed on the acceleration. The translational acceleration does not necessarily vary smoothly. Tracking of a non-smooth acceleration causes the vehicle attitude to exhibit undesirable transients and poor pointing stability behavior. In the alternative method, the two-point boundary value problem is not solved at each time step. A smooth reference position profile is computed. The profile is recomputed only when the control errors get sufficiently large. The nominal attitude is still required to track the smooth reference acceleration command. A steering logic is proposed that controls the position and velocity errors about the reference profile by perturbing the attitude slightly about the nominal attitude. The overall pointing behavior is therefore smooth, greatly reducing the degree of pointing instability.

Singh, Gurkirpal↗
NASA NTRS2012

Alternative Fuels Research Laboratory

NASA Glenn has invested over $1.5 million in engineering, and infrastructure upgrades to renovate an existing test facility at the NASA Glenn Research Center (GRC), which is now being used as an Alternative Fuels Laboratory. Facility systems have demonstrated reliability and consistency for continuous and safe operations in Fischer-Tropsch (F-T) synthesis and thermal stability testing. This effort is supported by the NASA Fundamental Aeronautics Subsonic Fixed Wing project. The purpose of this test facility is to conduct bench scale F-T catalyst screening experiments. These experiments require the use of a synthesis gas feedstock, which will enable the investigation of F-T reaction kinetics, product yields and hydrocarbon distributions. Currently the facility has the capability of performing three simultaneous reactor screening tests, along with a fourth fixed-bed reactor for catalyst activation studies. Product gas composition and performance data can be continuously obtained with an automated gas sampling system, which directly connects the reactors to a micro-gas chromatograph (micro GC). Liquid and molten product samples are collected intermittently and are analyzed by injecting as a diluted sample into designated gas chromatograph units. The test facility also has the capability of performing thermal stability experiments of alternative aviation fuels with the use of a Hot Liquid Process Simulator (HLPS) (Ref. 1) in accordance to ASTM D 3241 "Thermal Oxidation Stability of Aviation Fuels" (JFTOT method) (Ref. 2). An Ellipsometer will be used to study fuel fouling thicknesses on heated tubes from the HLPS experiments. A detailed overview of the test facility systems and capabilities are described in this paper.

Surgenor, Angela D.↗
NASA NTRS2008

Jet Engine Fan Blade Containment Using an Alternate Geometry

With a goal of reducing jet engine weight, simulations of a fan blade containment system with an alternate geometry were tested and analyzed. A projectile simulating a fan blade was shot at two alternate geometry containment case configurations using a gas gun. The first configuration was a flat plate representing a standard case configuration. The second configuration was a flat plate with a radially convex curve section at the impact point. The curved surface was designed to force the blade to deform plastically, dissipating energy before the full impact of the blade is received by the plate. The curved case was able to tolerate a higher impact velocity before failure. The computational model was developed and correlated with the tests and a weight savings assessment was performed. For the particular test configuration used in this study the ballistic impact velocity of the curved plate was approximately 60 m/s (200 ft/s) greater than that of the flat plate. For the computational model to successfully duplicate the test, the very high strain rate behavior of the materials had to be incorporated.

Carney, K.S.↗
NASA NTRS2007

Validation of Alternatives to Aliphatic Isocyanate Polyurethanes

The National Aeronautics and Space Administration (NASA) Headquarters chartered the Acquisition Pollution Prevention (AP2) Office to coordinate agency activities affecting pollution prevention issues identified during system and component acquisition and sustainment processes. The primary objective of this effort is to demonstrate and validate alternatives to aliphatic isocyanate polyurethane coatings. Successful completion of this project will result in one or more isocyanate-free coating systems qualified for use at Air Force Space Command (AFSPC) and NASA centers participating in this study. The objective of this project is to qualify the candidates under the specifications for the standard system. This project will compare coating performance of the proposed alternatives to existing coating systems or standards.

Curran, Jerome↗
NASA NTRS2014

An Alternate Configuration of the Multi-Mission Space Exploration Vehicle

The NASA Multi-Mission Space Exploration Vehicle (MMSEV) Team has developed an alternate configuration of the vehicle that can be used as a lunar lander. The MMSEV was originally conceived of during the Constellation program as the successor to the Apollo lunar rover as a pressurized rover for two-person, multiday excursions on the lunar surface. Following the cancellation of the Constellation program, the MMSEV has been reconfigured to serve as a free-flying scout vehicle for exploration of a Near Earth Asteroid and is also being assessed for use as a Habitable Airlock in a Cislunar microgravity spacecraft. The Alternate MMSEV (AMMSEV) variant of the MMSEV would serve as the transport vehicle for a four-person lunar crew, providing descent from an orbiting spacecraft or space station and ascent back to the spaceborne asset. This paper will provide a high level overview of the MMSEV and preliminary results from human-in-the-loop testing.

Howard, Robert L., Jr.↗
NASA NTRS2014

Designing an Alternate Mission Operations Control Room

The Huntsville Operations Support Center (HOSC) is a multi-project facility that is responsible for 24x7 real-time International Space Station (ISS) payload operations management, integration, and control and has the capability to support small satellite projects and will provide real-time support for SLS launches. The HOSC is a serviceoriented/ highly available operations center for ISS payloads-directly supporting science teams across the world responsible for the payloads. The HOSC is required to endure an annual 2-day power outage event for facility preventive maintenance and safety inspection of the core electro-mechanical systems. While complete system shut-downs are against the grain of a highly available sub-system, the entire facility must be powered down for a weekend for environmental and safety purposes. The consequence of this ground system outage is far reaching: any science performed on ISS during this outage weekend is lost. Engineering efforts were focused to maximize the ISS investment by engineering a suitable solution capable of continuing HOSC services while supporting safety requirements. The HOSC Power Outage Contingency (HPOC) System is a physically diversified compliment of systems capable of providing identified real-time services for the duration of a planned power outage condition from an alternate control room. HPOC was designed to maintain ISS payload operations for approximately three continuous days during planned HOSC power outages and support a local Payload Operations Team, International Partners, as well as remote users from the alternate control room located in another building. This paper presents the HPOC architecture and lessons learned during testing and the planned maiden operational commissioning. Additionally, this paper documents the necessity of an HPOC capability given the unplanned HOSC Facility power outage on April 27th, 2011, as a result of the tornado outbreak that damaged the electrical grid to such a degree that significantly inhibited the Tennessee Valley Authority's ability to transmit electricity throughout the North Alabama region.

Montgomery, Patty↗
NASA NTRS2014

Designing an Alternate Mission Operations Control Room

The Huntsville Operations Support Center (HOSC) is a multi-project facility that is responsible for 24x7 real-time International Space Station (ISS) payload operations management, integration, and control and has the capability to support small satellite projects and will provide real-time support for SLS launches. The HOSC is a service-oriented/ highly available operations center for ISS payloads-directly supporting science teams across the world responsible for the payloads. The HOSC is required to endure an annual 2-day power outage event for facility preventive maintenance and safety inspection of the core electro-mechanical systems. While complete system shut-downs are against the grain of a highly available sub-system, the entire facility must be powered down for a weekend for environmental and safety purposes. The consequence of this ground system outage is far reaching: any science performed on ISS during this outage weekend is lost. Engineering efforts were focused to maximize the ISS investment by engineering a suitable solution capable of continuing HOSC services while supporting safety requirements. The HOSC Power Outage Contingency (HPOC) System is a physically diversified compliment of systems capable of providing identified real-time services for the duration of a planned power outage condition from an alternate control room. HPOC was designed to maintain ISS payload operations for approximately three continuous days during planned HOSC power outages and support a local Payload Operations Team, International Partners, as well as remote users from the alternate control room located in another building.

Montgomery, Patty↗
NASA NTRS2014

The Sensitivity of WRF Daily Summertime Simulations over West Africa to Alternative Parameterizations. Part 1: African Wave Circulation

The performance of the NCAR Weather Research and Forecasting Model (WRF) as a West African regional-atmospheric model is evaluated. The study tests the sensitivity of WRF-simulated vorticity maxima associated with African easterly waves to 64 combinations of alternative parameterizations in a series of simulations in September. In all, 104 simulations of 12-day duration during 11 consecutive years are examined. The 64 combinations combine WRF parameterizations of cumulus convection, radiation transfer, surface hydrology, and PBL physics. Simulated daily and mean circulation results are validated against NASA's Modern-Era Retrospective Analysis for Research and Applications (MERRA) and NCEP/Department of Energy Global Reanalysis 2. Precipitation is considered in a second part of this two-part paper. A wide range of 700-hPa vorticity validation scores demonstrates the influence of alternative parameterizations. The best WRF performers achieve correlations against reanalysis of 0.40-0.60 and realistic amplitudes of spatiotemporal variability for the 2006 focus year while a parallel-benchmark simulation by the NASA Regional Model-3 (RM3) achieves higher correlations, but less realistic spatiotemporal variability. The largest favorable impact on WRF-vorticity validation is achieved by selecting the Grell-Devenyi cumulus convection scheme, resulting in higher correlations against reanalysis than simulations using the Kain-Fritch convection. Other parameterizations have less-obvious impact, although WRF configurations incorporating one surface model and PBL scheme consistently performed poorly. A comparison of reanalysis circulation against two NASA radiosonde stations confirms that both reanalyses represent observations well enough to validate the WRF results. Validation statistics for optimized WRF configurations simulating the parallel period during 10 additional years are less favorable than for 2006.

variability↗
NASA NTRS2015

Results of the Alternative Water Processor Test, A Novel Technology for Exploration Wastewater Remediation

Biologically‐based water recovery systems are a regenerative, low energy alternative to physiochemical processes to reclaim water from wastewater. This paper summarizes the results of the Alternative Water Processor (AWP) test conducted over one year. The AWP recovered 90% of water from four crewmembers using (4) membrane aerated bioreactors (MABRs) to remove carbon and nitrogen from an exploration mission wastewater, including urine, hygiene, laundry and humidity condensate. Downstream, a coupled forward and reverse osmosis system removed large organics and inorganic salts from the biological system effluent. The system exceeded the overall objectives of the test by recovering 90% of the influent wastewater processed and a 29% reduction of consumables from the current state of the art water recovery system on the International Space Station (ISS). However the biological system fell short of its test goals, failing to remove 75% and 90% of the influent ammonium and organic carbon, respectively. Despite not meeting its test goals, the BWP demonstrated the feasibility of an attachedgrowth biological system for simultaneous nitrification and denitrification, an innovative, volume and consumable‐saving design that doesn't require toxic pretreatment. This paper will explain the reasons for this and will discuss steps to optimize each subsystem to increase effluent quality from the MABRs and the FOST to advance the system.

Leticia Vega↗
NASA NTRS2015

NASA and ESA Collaboration on Hexavalent Chrome Alternatives - Pretreatments with Primers Screening Final Test Report

Hexavalent chromium (hex chrome or Cr(VI)) is a widely used element within applied coating systems because of its self-healing and corrosion-resistant properties. The replacement of hex chrome in the processing of aluminum for aviation and aerospace applications remains a goal of great significance. Aluminum is the major manufacturing material of structures and components in the space flight arena. The National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA) are engaged in a collaborative effort to test and evaluate alternatives to hexavalent chromium containing corrosion coating systems. NASA and ESA share common risks related to material obsolescence associated with hexavalent chromium used in corrosion-resistant coatings. In the United States, Occupational Safety and Health Administration (OSHA) studies have concluded that hexavalent chromium is carcinogenic and poses significant risk to human health. On May 5, 2011, amendments to the Defense Federal Acquisition Regulation Supplement (DFARS) were issued in the Federal Register. Subpart 223.73 prohibits contracts from requiring hexavalent chromium in deliverables unless certain exceptions apply. Subpart 252.223-7008 provides the contract clause prohibiting contractors and subcontractors from using or delivering hexavalent chromium in a concentration greater than 0.1 percent by weight for all new contracts associated with supplies, maintenance and repair services, and construction materials. ESA faces its own increasingly stringent regulations within European directives such as Registration, Evaluation, Authorization and Restriction of Chemical (REACH) substances and the Restriction of Hazardous Substances Directive (RoHS) which have set a mid-2017 sunset date for hexavalent chromium. NASA and ESA continue to search for an alternative to hexavalent chromium in coatings applications that meet their performance requirements in corrosion protection, cost, operability, and health and safety, while typically specifying that performance must be equal to or greater than existing systems. The overall objective of the collaborative effort between NASA TEERM and ESA is to test and evaluate coating systems (pretreatments, pretreatments with primer, and pretreatments with primer and topcoat) as replacements for hexavalent chrome coatings in aerospace applications. This objective will be accomplished by testing promising coatings identified from previous NASA, ESA, Department of Defense (DOD), and other project experience. Additionally, several new materials will be analyzed according to ESA-identified specifications.

coating↗
NASA NTRS2013

Development and Integration of an Advanced Stirling Convertor Linear Alternator Model for a Tool Simulating Convertor Performance and Creating Phasor Diagrams

A simple model of the Advanced Stirling Convertors (ASC) linear alternator and an AC bus controller has been developed and combined with a previously developed thermodynamic model of the convertor for a more complete simulation and analysis of the system performance. The model was developed using Sage, a 1-D thermodynamic modeling program that now includes electro-magnetic components. The convertor, consisting of a free-piston Stirling engine combined with a linear alternator, has sufficiently sinusoidal steady-state behavior to allow for phasor analysis of the forces and voltages acting in the system. A MATLAB graphical user interface (GUI) has been developed to interface with the Sage software for simplified use of the ASC model, calculation of forces, and automated creation of phasor diagrams. The GUI allows the user to vary convertor parameters while fixing different input or output parameters and observe the effect on the phasor diagrams or system performance. The new ASC model and GUI help create a better understanding of the relationship between the electrical component voltages and mechanical forces. This allows better insight into the overall convertor dynamics and performance.

Metscher, Jonathan F.↗