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All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Progress in Red vs. Green Propellant Operations: ASCENT Load Operations Lessons Learned

The Green Propellant Infusion Mission (GPIM) [1] is a NASA Space Technology Mission Directorate (STMD) effort to establish via demonstration ASCENT propellant (Advanced Space Craft Energetic Non-Toxic propellant, formerly referred to as AF-M315E) ground operations through on –orbit performance. ASCENT was developed by Air Force Research Laboratory (AFRL) as an increased energy density, reduced toxicity and reduced hazard monopropellant formulation relative to hydrazine. The GPIM team was led by Ball Aerospace and Technologies Corporation (BATC) as Program Management and Principal Investigator with AFRL, Aerojet-Rocketdyne (AR), the United States Space Force Space and Missile Systems Center (USSF/SMC), NASA Glenn Research Center (GRC), NASA Goddard Space Flight Center (GSFC), and NASA Kennedy Space Center (KSC) as Co-Investigators. The AFRL co-investigator role in the GPIM program was to develop the Propellant Ground Support Equipment (PGSE), associated Standard Operating Procedures (SOP) and Check Lists (CL), propellant load, propellant specification standard conventions and analysis methods, decontamination and waste disposal practices. This paper will discuss lessons learned in documentation, crew composition and readiness, equipment readiness, propellant readiness and potential improvements in the PGSE design.

Anthony P Zuttarelli↗
NASA NTRSDate not supplied

Research Needs for Developing Qualification Standards for Flight Simulation Training Devices with Head Mounted Displays

This presentation discusses research needs to support evidence-based qualification standards for Flight Simulation Training Devices (FSTDs) with head mounted displays (HMDs). Currently, the FAA and EASA have no qualification standards specifically for FSTDs using HMDs and extended reality (XR) visuals, and existing qualification standards may not be sufficient. Special Conditions can be prescribed for the evaluation and qualification of individual devices, but these Special Conditions need to be assessed and adjusted on a case-by-case basis resulting in an elaborate process. Furthermore, test tolerances used in Special Conditions are often based on conventional visual systems and may not be adequate. This presentation first identifies gaps in the current knowledge of using HMDs in pilot training, and, more specifically, using HMDs in the training of manual aircraft control with motion cues. Next, research is proposed to help close these gaps, inform the development of qualification criteria and tolerances, and guide efforts to update regulations. The Vertical Motion Simulator (VMS) at NASA Ames Research Center, with its large motion capability, is currently undergoing significant upgrades including a state-of-the-art out-the-window visual system. In addition, an HMD capability will be introduced to use in conjunction with the conventional visual system. With its long history of setting standards in the simulation industry, the VMS is the ultimate tool to conduct research that could help accelerate the development of standards for the use of HMDs in FSTDs. The goal of the talk is ultimately to spark a discussion about the research needs and priorities to best serve the development of new qualification standards.

XR↗
NASA NTRS1988

Data interfaces to the Space Station information system

The general form of the information system to be implemented to provide the broad and flexible services required to support the diverse needs of the U.S. Space Station is discussed. Emphasis is placed on the interfaces to the SSIS (Space Station Information System) and major interfaces within the SSIS. A central theme of the SSIS is the use of international standards, where appropriate and available. These standards include those of the International Organization for Standards (ISO), the Telegraph and Telephone Consultative Committee (CCITT), and the Consultative Committee for Space Data Systems (CCSDS). The specific standards selected or under consideration are enumerated. The effect of the selections on the interfaces visible to users of the SSIS are described, and a status report on the progress of official adoption of the standards is presented.

Carper, Richard↗
NASA NTRS2020

UAS Pilot Assessments of Display and Alerting for the Airborne Collision Avoidance System XU

Unmanned aircraft systems (UAS) must comply with specific standards to operate in the National Airspace System (NAS). Among the requirements are the detect and avoid (DAA) capabilities, which include display, alerting, and guidance specifications. Previous studies have queried pilots for their subjective feedback on these display elements on earlier systems; the present study sought pilot evaluations with an initial iteration of the unmanned variant of a Next Generation Airborne Collision Avoidance System (ACAS XU). Sixteen participants piloted simulated aircraft with both standalone and integrated DAA displays. Their opinions were gathered using post-block and post-simulation questionnaires as well as guided debriefs. The data showed pilots had better understanding and comfort with the system when using an integrated display. Pilots also rated ACAS Xu alerting and guidance as generally acceptable and effective. Implications for further development of ACAS XU and DAA displays are discussed.

UAS↗
NASA NTRSDate not supplied

UAS Pilot Assessments of Display and Alerting for the Airborne Collision Avoidance System XU

Unmanned aircraft systems (UAS) must comply with specific standards to operate in the National Airspace System (NAS). Among the requirements are the detect and avoid (DAA) capabilities, which include display, alerting, and guidance specifications. Previous studies have queried pilots for their subjective feedback on these display elements on earlier systems; the present study sought pilot evaluations with an initial iteration of the unmanned variant of a Next Generation Airborne Collision Avoidance System (ACAS XU). Sixteen participants piloted simulated aircraft with both standalone and integrated DAA displays. Their opinions were gathered using post-block and post-simulation questionnaires as well as guided debriefs. The data showed pilots had better understanding and comfort with the system when using an integrated display. Pilots also rated ACAS Xu alerting and guidance as generally acceptable and effective. Implications for further development of ACAS XU and DAA displays are discussed.

unmanned aircraft systems↗
NASA NTRS2020

UAS Pilot Assessments of Display and Alerting for the Next Generation Airborne Avoidance System

Unmanned aircraft systems (UAS) must comply with specific standards to operate in the National Airspace System (NAS). Among the requirements are the detect and avoid (DAA) capabilities, which include display, alerting, and guidance specifications. Previous studies have queried pilots for their subjective feedback on these display elements on earlier systems; the present study sought pilot evaluations with an initial iteration of the unmanned variant of a Next Generation Airborne Collision Avoidance System (ACAS XU). Sixteen participants piloted simulated aircraft with both standalone and integrated DAA displays. Their opinions were gathered using post-block and post-simulation questionnaires as well as guided debriefs. The data showed pilots had better understanding and comfort with the system when using an integrated display. Pilots also rated ACAS Xu alerting and guidance as generally acceptable and effective. Implications for further development of ACAS XU and DAA displays are discussed.

unmanned aircraft systems↗
NASA NTRSDate not supplied

UAS Pilot Assessments of Display and Alerting for the Next Generation Airborne Collision Avoidance System Xu

Unmanned aircraft systems (UAS) must comply with specific standards to operate in the National Airspace System (NAS). Among the requirements are the detect and avoid (DAA) capabilities, which include display, alerting, and guidance specifications. Previous studies have queried pilots for their subjective feedback on these display elements on earlier systems; the present study sought pilot evaluations with an initial iteration of the unmanned variant of a Next Generation Airborne Collision Avoidance System (ACAS XU). Sixteen participants piloted simulated aircraft with both standalone and integrated DAA displays. Their opinions were gathered using post-block and post-simulation questionnaires as well as guided debriefs. The data showed pilots had better understanding and comfort with the system when using an integrated display. Pilots also rated ACAS Xu alerting and guidance as generally acceptable and effective. Implications for further development of ACAS XU and DAA displays are discussed.

unmanned aircraft systems↗
NASA NTRS2013

Applications of Automation Methods for Nonlinear Fracture Test Analysis

Using automated and standardized computer tools to calculate the pertinent test result values has several advantages such as: 1. allowing high-fidelity solutions to complex nonlinear phenomena that would be impractical to express in written equation form, 2. eliminating errors associated with the interpretation and programing of analysis procedures from the text of test standards, 3. lessening the need for expertise in the areas of solid mechanics, fracture mechanics, numerical methods, and/or finite element modeling, to achieve sound results, 4. and providing one computer tool and/or one set of solutions for all users for a more "standardized" answer. In summary, this approach allows a non-expert with rudimentary training to get the best practical solution based on the latest understanding with minimum difficulty.Other existing ASTM standards that cover complicated phenomena use standard computer programs: 1. ASTM C1340/C1340M-10- Standard Practice for Estimation of Heat Gain or Loss Through Ceilings Under Attics Containing Radiant Barriers by Use of a Computer Program 2. ASTM F 2815 - Standard Practice for Chemical Permeation through Protective Clothing Materials: Testing Data Analysis by Use of a Computer Program 3. ASTM E2807 - Standard Specification for 3D Imaging Data Exchange, Version 1.0 The verification, validation, and round-robin processes required of a computer tool closely parallel the methods that are used to ensure the solution validity for equations included in test standard. The use of automated analysis tools allows the creation and practical implementation of advanced fracture mechanics test standards that capture the physics of a nonlinear fracture mechanics problem without adding undue burden or expense to the user. The presented approach forms a bridge between the equation-based fracture testing standards of today and the next generation of standards solving complex problems through analysis automation.

Allen, Phillip A.↗
NASA NTRS2007

The CEOS/GEO Constellation Concept

The Constellation concept was first proposed during a discussion at the 19th CEOS Plenary, in London, in November 2005. The first Paper of the Constellation Concept was presented at the CEOS Strategic Implementation Team meeting (SIT-18), in Frascati, in March 2006, and strongly endorsed by the CEOS Principals. The concept attempts to provide agencies with tools for implementation of the elements that have been previously discussed in international forums (GEO Work Plan, GCOS Implementation Plan). This provides a solid foundation from the community providing requirements. Though agency spending is governed by national requirements, CEOS seeks synergies among member agency programs to fulfil GEOSS requirements, defining guidelines and standards to help agencies to determine from the outset what can be achieved. The constellations concept will allow the development of a commonalties approach among different agencies. At the heart of the application of the Constellations concept is the definition of a series of standards (specific to each Constellation) - required to be satisfied for any mission to be included in the constellation - and a process of recognition/acceptance, whereby an agency applies to SIT to have one or more of its missions (ideally from the outset of planning) recognised as meeting the constellation standards and thereby satisfying the relevant user community needs.

Cramer, Bryant↗
NASA NTRS1991

Advanced techniques and technology for efficient data storage, access, and transfer

Advanced techniques for efficiently representing most forms of data are being implemented in practical hardware and software form through the joint efforts of three NASA centers. These techniques adapt to local statistical variations to continually provide near optimum code efficiency when representing data without error. Demonstrated in several earlier space applications, these techniques are the basis of initial NASA data compression standards specifications. Since the techniques clearly apply to most NASA science data, NASA invested in the development of both hardware and software implementations for general use. This investment includes high-speed single-chip very large scale integration (VLSI) coding and decoding modules as well as machine-transferrable software routines. The hardware chips were tested in the laboratory at data rates as high as 700 Mbits/s. A coding module's definition includes a predictive preprocessing stage and a powerful adaptive coding stage. The function of the preprocessor is to optimally process incoming data into a standard form data source that the second stage can handle.The built-in preprocessor of the VLSI coder chips is ideal for high-speed sampled data applications such as imaging and high-quality audio, but additionally, the second stage adaptive coder can be used separately with any source that can be externally preprocessed into the 'standard form'. This generic functionality assures that the applicability of these techniques and their recent high-speed implementations should be equally broad outside of NASA.

Rice, Robert F.↗
NASA NTRS1999

The Design of a Fault-Tolerant COTS-Based Bus Architecture

In this paper, we report our experiences and findings on the design of a fault-tolerant bus architecture comprised of two COTS buses, the IEEE 1394 and the 12C. This fault-tolerant bus is the backbone system bus for the avionics architecture of the X2000 program at the Jet Propulsion Laboratory. COTS buses are attractive because of the availability of low cost commercial products. However, they are not specifically designed for highly reliable applications such as long-life deep-space missions. The X2000 design team has devised a multi-level fault tolerance approach to compensate for this shortcoming of COTS buses. First, the approach enhances the fault tolerance capabilities of the IEEE 1394 and 12 C buses by adding a layer of fault handling hardware and software. Second, algorithms are developed to enable the IEEE 1394 and the 12 C buses assist each other to isolate and recovery from faults. Third, the set of IEEE 1394 and 12 C buses is duplicated to further enhance system reliability. The X2000 design team has paid special attention to guarantee that all fault tolerance provisions will not cause the bus design to deviate from the commercial standard specifications. Otherwise, the economic attractiveness of using COTS will be diminished. The hardware and software design of the X2000 fault-tolerant bus are being implemented and flight hardware will be delivered to the ST4 and Europa Orbiter missions.

Chau, Savio N.↗
NASA NTRS2012

Auto Code Generation for Simulink-Based Attitude Determination Control System

This paper details the work done to auto generate C code from a Simulink-Based Attitude Determination Control System (ADCS) to be used in target platforms. NASA Marshall Engineers have developed an ADCS Simulink simulation to be used as a component for the flight software of a satellite. This generated code can be used for carrying out Hardware in the loop testing of components for a satellite in a convenient manner with easily tunable parameters. Due to the nature of the embedded hardware components such as microcontrollers, this simulation code cannot be used directly, as it is, on the target platform and must first be converted into C code; this process is known as auto code generation. In order to generate C code from this simulation; it must be modified to follow specific standards set in place by the auto code generation process. Some of these modifications include changing certain simulation models into their atomic representations which can bring new complications into the simulation. The execution order of these models can change based on these modifications. Great care must be taken in order to maintain a working simulation that can also be used for auto code generation. After modifying the ADCS simulation for the auto code generation process, it is shown that the difference between the output data of the former and that of the latter is between acceptable bounds. Thus, it can be said that the process is a success since all the output requirements are met. Based on these results, it can be argued that this generated C code can be effectively used by any desired platform as long as it follows the specific memory requirements established in the Simulink Model.

MolinaFraticelli, Jose Carlos↗
NASA NTRS1968

Test control.

Environmental test control methods for improving quality and reducing costs, noting standardized specifications and information collection for administration

Dundas, H. R.↗
NASA NTRS1969

Tool simplifies machining of pipe ends for precision welding

Single tool prepares a pipe end for precision welding by simultaneously performing internal machining, end facing, and bevel cutting to specification standards. The machining operation requires only one milling adjustment, can be performed quickly, and produces the high quality pipe-end configurations required to ensure precision-welded joints.

Matus, S. T.↗
NASA NTRS1974

The NASA program for standardizing silicon solar cells

The present work describes briefly the goals of the recently organized Standardized Space Power Systems Office and its program for developing low-cost, standard power system components for spacecraft. The first step is the development of standard specifications for solar cells and covers. These include: (1) physical dimensions, materials of construction, appearance and integrity of solar cell and coverglass; (2) electrical performance characteristics of solar cell and optical characteristics of coverglass; and (3) sampling, inspection, and electrical and environmental tests needed to demonstrate compliance with the above specifications.

Bifano, W.J.↗
NASA NTRS1975

Program design by a multidisciplinary team

The use of software engineering aids in the design of a structural finite-element analysis computer program for the STAR-100 computer is described. Nested functional diagrams to aid in communication among design team members were used, and a standardized specification format to describe modules designed by various members was adopted. This is a report of current work in which use of the functional diagrams provided continuity and helped resolve some of the problems arising in this long-running part-time project.

Voigt, S.↗
NASA NTRS1977

Electrically Conductive Paints for Satellites

A program was conducted to develop and test electrically conductive paint coatings for spacecraft. A wide variety of organic and inorganic coatings were formulated using conductive binders, conductive pigments, and similar approaches. Z-93, IITRI's standard specification inorganic thermal control coating, exhibits good electrical properties and is a very space-stable coating system. Several coatings based on a conductive pigment (antimony-doped tin oxide) in silicone and silicate binders offer considerable promise. Paint systems using commercially available conductive polymers also appear to be of interest, but will require substantial development. Evaluations were made based on electrical conductivity, paint physical properties, and the stability of spectral reflectance in space environment testing.

Gilligan, J. E.↗