SEARCH · Search NASA

Results for “command generation process”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4

All sources NASA NTRS DOE OSTI

NASA NTRS1982

Space telescope - Meeting the pointing control challenge with today's technology

The pointing control system of the Space Telescope, which provides target-to-target maneuvering capability and precision pointing on the target star (with 0.007-arcsec stability and 0.01-arcsec accuracy), is described. Spacecraft attitude control is undertaken by onboard computer processing of attitude and rate sensor data that generates reaction wheel torque commands. The Space Telescope Operations Control Center communicates with the Space Telescope via the synchronous altitude tracking and data relay satellite system, and determines vehicle attitude more precisely by means of sun sensors, magnetometers and fixed-head star trackers. Such disturbance torques as those of gravity gradients and aerodynamics act on the Space Telescope, causing the speeds of the four reaction wheels to increase. In order to prevent the wheels from reaching a speed-saturated condition, a momentum control system is provided for the management of reaction wheel speed buildup. Attention is given to development testing and control hardware investigations and improvements.

Dougherty, H.↗

NASA NTRS1984

Space Telescope pointing control

The Space Telescope, a long life, high performance spacecraft deployed by the Space Shuttle, will carry five scientific instruments on its first mission. Its pointing control system will permit target-to-target maneuvering and precision pointing on a target star to support scientific objectives. Spacecraft attitude control is achieved by onboard computer processing of attitude and rate sensor data to generate reaction wheel torque commands. A momentum management control system is provided to desaturate the reaction wheels. This paper discusses the pointing control system and the control hardware investigations and improvements leading to system design.

Dougherty, H.↗

NASA NTRS2006

Ground Processing of Data From the Mars Exploration Rovers

A computer program implements the Earth side of the protocol that governs the transfer of data files generated by the Mars Exploration Rovers. It also provides tools for viewing data in these files and integrating data-product files into automated and manual processes. It reconstitutes files from telemetry data packets. Even if only one packet is received, metadata provide enough information to enable this program to identify and use partial data products. This software can generate commands to acknowledge received files and retransmit missed parts of files, or it can feed a manual process to make decisions about retransmission. The software uses an Extensible Markup Language (XML) data dictionary to provide a generic capability for displaying files of basic types, and uses external "plug-in" application programs to provide more sophisticated displays. This program makes data products available with very low latency, and can trigger automated actions when complete or partial products are received. The software is easy to install and use. The only system requirement for installing the software is a Java J2SE 1.4 platform. Several instances of the software can be executed simultaneously on the same machine.

Wright, Jesse↗

NASA NTRS1994

Mission Operations Centers (MOCs): Integrating key spacecraft ground data system components

In an environment characterized by decreasing budgets, limited system development time, and user needs for increased capabilities, the Mission Operations Division (MOD) at the National Aeronautics and Space Administration Goddard Space Flight Center initiated a new, cost-effective concept in developing its spacecraft ground data systems: the Mission Operations Center (MOC). In the MOC approach, key components are integrated into a comprehensive and cohesive spacecraft planning, monitoring, command, and control system with a single, state-of-the-art graphical user interface. The MOD is currently implementing MOC's, which feature a common, reusable, and extendable system architecture, to support the X-Ray Timing Explorer (XTE), Tropical Rainfall Measuring Mission (TRMM), and Advanced Composition Explorer (ACE) missions. As a result of the MOC approach, mission operations are integrated, and users can, with a single system, perform real-time health and safety monitoring, real-time command and control, real-time attitude processing, real-time and predictive graphical spacecraft monitoring, trend analysis, mission planning and scheduling, command generation and management, network scheduling, guide star selection, and (using an expert system) spacecraft monitoring and fault isolation. The MOD is also implementing its test and training simulators under the new MOC management structure. This paper describes the MOC concept, the management approaches used in developing MOC systems, the technologies employed and the development process improvement initiatives applied in implementing MOC systems, and the expected benefits to both the user and the mission project in using the MOC approach.

Harbaugh, Randy↗

NASA NTRS1986

Space Telescope Antenna Pointing System analysis and test

The Space Telescope (ST), carrying five astronomy instruments, is a long-life spacecraft designed to achieve and maintain ultrafine stabilization jitter performance. The rms jitter specification for pointing performance is 7 marcsec (1sigma) during periods of scientific observation. Spacecraft attitude control is achieved by onboard computer processing of attitude and rate sensor data to generate reaction-wheel torque commands. The ST Antenna Pointing System is used to position a high-gain antenna for relaying science and engineering data from the spacecraft to the ground station.

Dodder, R.↗

NASA NTRS1989

Computational fluid dynamics analysis of space shuttle main propulsion feed line 17-inch disconnect valves

A steady incompressible three-dimensional (3-D) viscous flow analysis was conducted for the Space Shuttle Main Propulsion External Tank (ET)/Orbiter (ORB) propellant feed line quick separable 17-inch disconnect flapper valves for liquid oxygen (LO2) and liquid hydrogen (LH2). The main objectives of the analysis were to predict and correlate the hydrodynamic stability of the flappers and pressure drop with available water test data. Computational Fluid Dynamics (CFD) computer codes were procured at no cost from the public domain, and were modified and extended to carry out the disconnect flow analysis. The grid generator codes SVTGD3D and INGRID were obtained. NASA Ames Research Center supplied the flow solution code INS3D, and the color graphics code PLOT3D. A driver routine was developed to automate the grid generation process. Components such as pipes, elbows, and flappers can be generated with simple commands, and flapper angles can be varied easily. The flow solver INS3D code was modified to treat interior flappers, and other interfacing routines were developed, which include a turbulence model, a force/moment routine, a time-step routine, and initial and boundary conditions. In particular, an under-relaxation scheme was implemented to enhance the solution stability. Major physical assumptions and simplifications made in the analysis include the neglect of linkages, slightly reduced flapper diameter, and smooth solid surfaces. A grid size of 54 x 21 x 25 was employed for both the LO2 and LH2 units. Mixing length theory applied to turbulent shear flow in pipes formed the basis for the simple turbulence model. Results of the analysis are presented for LO2 and LH2 disconnects.

Kandula, Max↗

NASA NTRS2001

On-Orbit ACDS Performance of the Landsat 7 Spacecraft

Landsat 7 is part of NASA's Earth Science Enterprise (ESE). The ESE is committed to developing an understanding of the total Earth system, the effects of natural and human-induced changes on the global environment, and how natural processes affect humans and how humans affect them. The Landsat 7 satellite consists of the spacecraft bus which was provided under a NASA contract with Lockheed Martin Missiles and Space in Philadelphia, PA, and the Enhanced Thematic Mapper-Plus (ETM+) instrument, procured under a NASA contract with Raytheon Santa Barbara Remote Sensing, in Santa Barbara, CA. The Landsat 7 Attitude Control and Determination System (ACDS) provides many essential functions for the operation of the spacecraft bus and for ETM+. The ACDS maintains the required attitude and orbit at the degree of accuracy necessary for power generation, command and telemetry, thermal balance, image acquisition, Gimbaled X-Band Antenna (GXA) pointing and data for image post-processing. Descriptions of the Landsat 7 mission and the ACDS modes and requirements are presented. A brief summary of significant events of the on-orbit initialization and validation period are provided. Finally, the Landsat 7 product generation system is described and the impact that the ACDS performance has on the ground based image processing system is explored.

Sabelhaus, Phillip↗

NASA NTRS2011

Link Analysis in the Mission Planning Lab

The legacy communications link analysis software currently used at Wallops Flight Facility involves processes that are different for command destruct, radar, and telemetry. There is a clear advantage to developing an easy-to-use tool that combines all the processes in one application. Link Analysis in the Mission Planning Lab (MPL) uses custom software and algorithms integrated with Analytical Graphics Inc. Satellite Toolkit (AGI STK). The MPL link analysis tool uses pre/post-mission data to conduct a dynamic link analysis between ground assets and the launch vehicle. Just as the legacy methods do, the MPL link analysis tool calculates signal strength and signal- to-noise according to the accepted processes for command destruct, radar, and telemetry assets. Graphs and other custom data are generated rapidly in formats for reports and presentations. STK is used for analysis as well as to depict plume angles and antenna gain patterns in 3D. The MPL has developed two interfaces with the STK software (see figure). The first interface is an HTML utility, which was developed in Visual Basic to enhance analysis for plume modeling and to offer a more user friendly, flexible tool. A graphical user interface (GUI) written in MATLAB (see figure upper right-hand corner) is also used to quickly depict link budget information for multiple ground assets. This new method yields a dramatic decrease in the time it takes to provide launch managers with the required link budgets to make critical pre-mission decisions. The software code used for these two custom utilities is a product of NASA's MPL.

McCarthy, Jessica A.↗

NASA NTRS2012

MPST Software: MoonKommand

This software automatically processes Sally Ride Science (SRS) delivered MoonKAM camera control files (ccf) into uplink products for the GRAIL-A and GRAIL-B spacecraft as part of an education and public outreach (EPO) extension to the Grail Mission. Once properly validated and deemed safe for execution onboard the spacecraft, MoonKommand generates the command products via the Automated Sequence Processor (ASP) and generates uplink (.scmf) files for radiation to the Grail-A and/or Grail-B spacecraft. Any errors detected along the way are reported back to SRS via email. With Moon Kommand, SRS can control their EPO instrument as part of a fully automated process. Inputs are received from SRS as either image capture files (.ccficd) for new image requests, or downlink/delete files (.ccfdl) for requesting image downlink from the instrument and on-board memory management. The Moon - Kommand outputs are command and file-load (.scmf) files that will be uplinked by the Deep Space Network (DSN). Without MoonKommand software, uplink product generation for the MoonKAM instrument would be a manual process. The software is specific to the Moon - KAM instrument on the GRAIL mission. At the time of this writing, the GRAIL mission was making final preparations to begin the science phase, which was scheduled to continue until June 2012.

Kwok, John H.↗

NASA NTRS2010

AutoGen Version 5.0

Version 5.0 of the AutoGen software has been released. Previous versions, variously denoted Autogen and autogen, were reported in two articles: Automated Sequence Generation Process and Software (NPO-30746), Software Tech Briefs (Special Supplement to NASA Tech Briefs), September 2007, page 30, and Autogen Version 2.0 (NPO- 41501), NASA Tech Briefs, Vol. 31, No. 10 (October 2007), page 58. To recapitulate: AutoGen (now signifying automatic sequence generation ) automates the generation of sequences of commands in a standard format for uplink to spacecraft. AutoGen requires fewer workers than are needed for older manual sequence-generation processes, and greatly reduces sequence-generation times. The sequences are embodied in spacecraft activity sequence files (SASFs). AutoGen automates generation of SASFs by use of another previously reported program called APGEN. AutoGen encodes knowledge of different mission phases and of how the resultant commands must differ among the phases. AutoGen also provides means for customizing sequences through use of configuration files. The approach followed in developing AutoGen has involved encoding the behaviors of a system into a model and encoding algorithms for context-sensitive customizations of the modeled behaviors. This version of AutoGen addressed the MRO (Mars Reconnaissance Orbiter) primary science phase (PSP) mission phase. On previous Mars missions this phase has more commonly been referred to as mapping phase. This version addressed the unique aspects of sequencing orbital operations and specifically the mission specific adaptation of orbital operations for MRO. This version also includes capabilities for MRO s role in Mars relay support for UHF relay communications with the MER rovers and the Phoenix lander.

Gladden, Roy E.↗

NASA NTRS1993

The Mars Observer Camera ground data system

The Mars Observer Camera (MOC), launched on board the Mars Observer spacecraft in September 1992, is to be operated by a small team using large amounts of computer assistance. Here, we describe the architecture of the MOC Ground Data System, which is capable of taking imaging requests, generating imaging command sequences, receiving the acquired images, archiving them, and delivering them in several processed forms to the MOC user community, all with the need for only a limited amount of human interaction.

Caplinger, Michael↗

NASA NTRS2006

Establishment and Implementation of a Close Approach Evaluation and Avoidance Process for Earth Observing System Missions

In the fall of 2004, the Earth Science Mission Operations Project tasked the Goddard Space Flight Center (GSPC) Flight Dynamics Analysis Branch with establishment of a process to protect the high-value Earth Observing System (EOS) missions (Terra, Aqua, and Aura) from close approaches with space debris and other orbiting objects. An agreement between GSFC and the United States Strategic Command was put in place so that close approach predictions would be routinely generated. This paper describes the ESMO conjunction assessment process for the EOS satellites. Process details, including tools and algorithms developed, are discussed. Particular details for a predicted close approach between Terra and a piece of space debris that resulted in the execution of a debris avoidance maneuver are included. This close approach example is described in detail fiom the first screening identification through execution of the mitigation maneuver to illustrate both the process and lessons learned fiom its implementation.

Newman, Lauri↗

NASA NTRS2001

A Metadata Action Language

The data management problem comprises data processing and data tracking. Data processing is the creation of new data based on existing data sources. Data tracking consists of storing metadata descriptions of available data. This paper addresses the data management problem by casting it as an AI planning problem. Actions are data-processing commands, plans are dataflow programs and goals are metadata descriptions of desired data products. Data manipulation is simply plan generation and execution, and a key component of data tracking is inferring the effects of an observed plan. We introduce a new action language for data management domains, called ADILM. We discuss the connection between data processing and information integration and show how a language for the latter must be modified to support the former. The paper also discusses information gathering within a data-processing framework, and show how ADILM metadata expressions are a generalization of Local Completeness.

Golden, Keith↗

NASA NTRSDate not supplied

The 7 Year Evolution of EOS CA Support for Planning & Executing Risk Mitigation Maneuvers

This presentation will discuss the evolution of Collision Avoidance (CA) support for planning and executing Risk Mitigation Maneuvers (RMMs) for the Earth Observing System (EOS) Aqua, Aura, and Terra satellites within the seven-year period of January 2015 through December 2021. Several enhancements were implemented by the EOS team to expedite and improve the RMM planning and execution process, including updates to High Interest Event (HIE) analysis, maneuver preparation, maneuver ephemeris generation, conjunction event data screening, and maneuver commanding. As of 2022, these advancements allow the EOS team to plan and execute an RMM within 5 hours of identification with an accurate and low-risk solution. This represents a vast improvement from the 30 hours required to turn around an RMM back in 2015. In addition, the current process is substantially less error prone. Details of this progression and the specific aspects of each supporting component are explicated in the content of the presentation.

Syed Hasan↗

NASA NTRS1991

Macintosh II based space Telemetry and Command (MacTac) system

The general architecture and the principal functions of the Macintosh II based Telemetry and Command system, presently under development, are described, with attention given to custom telemetry cards, input/output interfaces, and the icon driven user interface. The MacTac is a low-cost, transportable, easy to use, compact system designed to meet the requirements specified by the Consultative Committeee for Space Data Systems while remaining flexible enough to support a wide variety of other user specific telemetry processing requirements, such as TDM data. In addition, the MacTac can accept or generate forward data (such as spacecraft commands), calculate and append a Polynomial Check Code, and output these data to NASCOM to provide full Telemetry and Command capability.

Dominy, Carol T.↗

NASA NTRS2004

Impact of Operating Context on the Use of Structure in Air Traffic Controller Cognitive Processes

This paper investigates the influence of structure on air traffic controllers cognitive processes in the TRACON, En Route, and Oceanic environments. Radar data and voice command analyses were conducted to support hypotheses generated through observations and interviews conducted at the various facilities. Three general types of structure-based abstractions (standard flows, groupings, and critical points) have been identified as being used in each context, though the details of their application varied in accordance with the constraints of the particular operational environment. Projection emerged as a key cognitive process aided by the structure-based abstractions, and there appears to be a significant difference between how time-based versus spatial-based projection is performed by controllers. It is recommended that consideration be given to the value provided by the structure-based abstractions to the controller as well as to maintain consistency between the type (time or spatial) of information support provided to the controller.

Davison, Hayley J.↗

NASA NTRS2014

Using AUTORAD for Cassini File Uplinks: Incorporating Automated Commanding into Mission Operations

As the Cassini spacecraft embarked on the Solstice Mission in October 2010, the flight operations team faced a significant challenge in planning and executing the continuing tour of the Saturnian system. Faced with budget cuts that reduced the science and engineering staff by over a third in size, new and streamlined processes had to be developed to allow the Cassini mission to maintain a high level of science data return with a lower amount of available resources while still minimizing the risk. Automation was deemed an important key in enabling mission operations with reduced workforce and the Cassini flight team has made this goal a priority for the Solstice Mission. The operations team learned about a utility called AUTORAD which would give the flight operations team the ability to program selected command files for radiation up to seven days in advance and help minimize the need for off-shift support that could deplete available staffing during the prime shift hours. This paper will describe how AUTORAD is being utilized by the Cassini flight operations team and the processes that were developed or modified to ensure that proper oversight and verification is maintained in the generation and execution of radiated command files.

Goo, Sherwin↗

NASA NTRS1991

Controlling Laboratory Processes From A Personal Computer

Computer program provides natural-language process control from IBM PC or compatible computer. Sets up process-control system that either runs without operator or run by workers who have limited programming skills. Includes three smaller programs. Two of them, written in FORTRAN 77, record data and control research processes. Third program, written in Pascal, generates FORTRAN subroutines used by other two programs to identify user commands with device-driving routines written by user. Also includes set of input data allowing user to define user commands to be executed by computer. Requires personal computer operating under MS-DOS with suitable hardware interfaces to all controlled devices. Also requires FORTRAN 77 compiler and device drivers written by user.

Will, H.↗