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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.

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All sourcesNASA NTRSDOE OSTI
NASA NTRS1994

A proven approach for more effective software development and maintenance

Modern space flight mission operations and associated ground data systems are increasingly dependent upon reliable, quality software. Critical functions such as command load preparation, health and status monitoring, communications link scheduling and conflict resolution, and transparent gateway protocol conversion are routinely performed by software. Given budget constraints and the ever increasing capabilities of processor technology, the next generation of control centers and data systems will be even more dependent upon software across all aspects of performance. A key challenge now is to implement improved engineering, management, and assurance processes for the development and maintenance of that software; processes that cost less, yield higher quality products, and that self-correct for continual improvement evolution. The NASA Goddard Space Flight Center has a unique experience base that can be readily tapped to help solve the software challenge. Over the past eighteen years, the Software Engineering Laboratory within the code 500 Flight Dynamics Division has evolved a software development and maintenance methodology that accommodates the unique characteristics of an organization while optimizing and continually improving the organization's software capabilities. This methodology relies upon measurement, analysis, and feedback much analogous to that of control loop systems. It is an approach with a time-tested track record proven through repeated applications across a broad range of operational software development and maintenance projects. This paper describes the software improvement methodology employed by the Software Engineering Laboratory, and how it has been exploited within the Flight Dynamics Division with GSFC Code 500. Examples of specific improvement in the software itself and its processes are presented to illustrate the effectiveness of the methodology. Finally, the initial findings are given when this methodology was applied across the mission operations and ground data systems software domains throughout Code 500.

Pajerski, Rose↗
NASA NTRS1994

Taking advantage of ground data systems attributes to achieve quality results in testing software

During the software development life cycle process, basic testing starts with the development team. At the end of the development process, an acceptance test is performed for the user to ensure that the deliverable is acceptable. Ideally, the delivery is an operational product with zero defects. However, the goal of zero defects is normally not achieved but is successful to various degrees. With the emphasis on building low cost ground support systems while maintaining a quality product, a key element in the test process is simulator capability. This paper reviews the Transportable Payload Operations Control Center (TPOCC) Advanced Spacecraft Simulator (TASS) test tool that is used in the acceptance test process for unmanned satellite operations control centers. The TASS is designed to support the development, test and operational environments of the Goddard Space Flight Center (GSFC) operations control centers. The TASS uses the same basic architecture as the operations control center. This architecture is characterized by its use of distributed processing, industry standards, commercial off-the-shelf (COTS) hardware and software components, and reusable software. The TASS uses much of the same TPOCC architecture and reusable software that the operations control center developer uses. The TASS also makes use of reusable simulator software in the mission specific versions of the TASS. Very little new software needs to be developed, mainly mission specific telemetry communication and command processing software. By taking advantage of the ground data system attributes, successful software reuse for operational systems provides the opportunity to extend the reuse concept into the test area. Consistency in test approach is a major step in achieving quality results.

Sigman, Clayton B.↗
NASA NTRS2014

Comparing On-Orbit and Ground Performance for an S-Band Software-Defined Radio

NASA's Space Communications and Navigation Testbed was installed on an external truss of the International Space Station in 2012. The testbed contains several software-defined radios (SDRs), including the Jet Propulsion Laboratory (JPL) SDR, which underwent performance testing throughout 2013 with NASAs Tracking and Data Relay Satellite System (TDRSS). On-orbit testing of the JPL SDR was conducted at S-band with the Glenn Goddard TDRSS waveform and compared against an extensive dataset collected on the ground prior to launch. This paper will focus on the development of a waveform power estimator on the ground post-launch and discuss the performance challenges associated with operating the power estimator in space.

International Space Station↗
NASA NTRS2014

Comparing On-Orbit and Ground Performance for an S-Band Software-Defined Radio

NASA's Space Communications and Navigation Testbed was installed on an external truss of the International Space Station in 2012. The testbed contains several software-defined radios (SDRs), including the Jet Propulsion Laboratory (JPL) SDR, which underwent performance testing throughout 2013 with NASA's Tracking and Data Relay Satellite System (TDRSS). On-orbit testing of the JPL SDR was conducted at S-band with the Glenn Goddard TDRSS waveform and compared against an extensive dataset collected on the ground prior to launch. This paper will focus on the development of a waveform power estimator on the ground post-launch and discuss the performance challenges associated with operating the power estimator in space.

waveforms↗
NASA NTRS1991

Hubble Space Telescope pointing control system: Designed for performance and mission operations

The Hubble Space Telescope was designed to be an orbiting astronomical observatory which could be operated in the same manner as ground based observatories. The design drivers for the pointing control system's hardware and software were the requirements of an absolute pointing accuracy of 4.8E-8 radians and pointing stability (jitter) of 3.4E-8 radians. Of comparable importance was the objective of providing a flexible command methodology and structure to enable seven day operational planning employing stored program command and real time command capability. The pointing control system hardware, software, safemode control schemes, ground system monitoring capability, and in-orbit results are reviewed.

Bradley, A.↗
NASA NTRS1976

Payload specialist station study. Volume 3: Program study cost estimates. Part 1: Work breakdown structure

The work breakdown structure (WBS) for the Payload Specialist Station (PSS) is presented. The WBS is divided into two elements--PSS contractor and mission unique requirements. In accordance with the study ground rules, it is assumed that a single contractor, hereafter referred to as PSS Contractor will perform the following: (1) provide C and D hardware (MFDS and elements of MMSE), except for GFE; (2) identify software requirements; (3) provide GSE and ground test software; and (4) perform systems engineering and integration in support of the Aft Flight Deck (AFD) C and D concept. The PSS Contractor WBS element encompasses a core or standardized PSS concept. Payload peculiar C and D requirements identified by users will originate as a part of the WBS element mission unique requirements; these requirements will be provided to the PSS Contractor for implementation.

Source record↗
NASA NTRS2014

Securing Ground Data System Applications for Space Operations

The increasing prevalence and sophistication of cyber attacks has prompted the Multimission Ground Systems and Services (MGSS) Program Office at Jet Propulsion Laboratory (JPL) to initiate the Common Access Manager (CAM) effort to protect software applications used in Ground Data Systems (GDSs) at JPL and other NASA Centers. The CAM software provides centralized services and software components used by GDS subsystems to meet access control requirements and ensure data integrity, confidentiality, and availability. In this paper we describe the CAM software; examples of its integration with spacecraft commanding software applications and an information management service; and measurements of its performance and reliability.

Security↗
NASA NTRS2006

A survey of ground operations tools developed to simulate the pointing of space telescopes and the design for WISE

WISE, the Wide Field Infrared Survey Explorer, is scheduled for launch in June 2010. The mission operations system for WISE requires a software modeling tool to help plan, integrate and simulate all spacecraft pointing and verify that no attitude constraints are violated. In the course of developing the requirements for this tool, an investigation was conducted into the design of similar tools for other space-based telescopes. This paper summarizes the ground software and processes used to plan and validate pointing for a selection of space telescopes; with this information as background, the design for WISE is presented.

ground system↗
NASA NTRS1979

The 25 kW power module evolution study. Part 3: Conceptual design for power module evolution. Volume 6: WBS and dictionary

Program elements of the power module (PM) system, are identified, structured, and defined according to the planned work breakdown structure. Efforts required to design, develop, manufacture, test, checkout, launch and operate a protoflight assembled 25 kW, 50 kW and 100 kW PM include the preparation and delivery of related software, government furnished equipment, space support equipment, ground support equipment, launch site verification software, orbital verification software, and all related data items.

Source record↗
NASA NTRS1991

Ground Systems Development Environment (GSDE) interface requirements analysis

A set of procedural and functional requirements are presented for the interface between software development environments and software integration and test systems used for space station ground systems software. The requirements focus on the need for centralized configuration management of software as it is transitioned from development to formal, target based testing. This concludes the GSDE Interface Requirements study. A summary is presented of findings concerning the interface itself, possible interface and prototyping directions for further study, and results of the investigation of the Cronus distributed applications environment.

Church, Victor E.↗
NASA NTRS1992

Experience with Ada on the F-18 High Alpha Research Vehicle Flight Test Program

Considerable experience was acquired with Ada at the NASA Dryden Flight Research Facility during the on-going High Alpha Technology Program. In this program, an F-18 aircraft was highly modified by the addition of thrust-vectoring vanes to the airframe. In addition, substantial alteration was made in the original quadruplex flight control system. The result is the High Alpha Research Vehicle. An additional research flight control computer was incorporated in each of the four channels. Software for the research flight control computer was written in Ada. To date, six releases of this software have been flown. This paper provides a detailed description of the modifications to the research flight control system. Efficient ground-testing of the software was accomplished by using simulations that used the Ada for portions of their software. These simulations are also described. Modifying and transferring the Ada for flight software to the software simulation configuration has allowed evaluation of this language. This paper also discusses such significant issues in using Ada as portability, modifiability, and testability as well as documentation requirements.

Regenie, Victoria A.↗
NASA NTRS1994

Experience with Ada on the F-18 High Alpha Research Vehicle flight test program

Considerable experience has been acquired with Ada at the NASA Dryden Flight Research Facility during the on-going High Alpha Technology Program. In this program, an F-18 aircraft has been highly modified by the addition of thrust-vectoring vanes to the airframe. In addition, substantial alteration was made in the original quadruplex flight control system. The result is the High Alpha Research Vehicle. An additional research flight control computer was incorporated in each of the four channels. Software for the research flight control computer was written Ada. To date, six releases of this software have been flown. This paper provides a detailed description of the modifications to the research flight control system. Efficient ground-testing of the software was accomplished by using simulations that used the Ada for portions of their software. These simulations are also described. Modifying and transferring the Ada flight software to the software simulation configuration has allowed evaluation of this language. This paper also discusses such significant issues in using Ada as portability, modifiability, and testability as well as documentation requirements.

Regenie, Victoria A.↗
NASA NTRS2014

Software Suite to Support In-Flight Characterization of Remote Sensing Systems

A characterization software suite was developed to facilitate NASA's in-flight characterization of commercial remote sensing systems. Characterization of aerial and satellite systems requires knowledge of ground characteristics, or ground truth. This information is typically obtained with instruments taking measurements prior to or during a remote sensing system overpass. Acquired ground-truth data, which can consist of hundreds of measurements with different data formats, must be processed before it can be used in the characterization. Accurate in-flight characterization of remote sensing systems relies on multiple field data acquisitions that are efficiently processed, with minimal error. To address the need for timely, reproducible ground-truth data, a characterization software suite was developed to automate the data processing methods. The characterization software suite is engineering code, requiring some prior knowledge and expertise to run. The suite consists of component scripts for each of the three main in-flight characterization types: radiometric, geometric, and spatial. The component scripts for the radiometric characterization operate primarily by reading the raw data acquired by the field instruments, combining it with other applicable information, and then reducing it to a format that is appropriate for input into MODTRAN (MODerate resolution atmospheric TRANsmission), an Air Force Research Laboratory-developed radiative transport code used to predict at-sensor measurements. The geometric scripts operate by comparing identified target locations from the remote sensing image to known target locations, producing circular error statistics defined by the Federal Geographic Data Committee Standards. The spatial scripts analyze a target edge within the image, and produce estimates of Relative Edge Response and the value of the Modulation Transfer Function at the Nyquist frequency. The software suite enables rapid, efficient, automated processing of ground truth data, which has been used to provide reproducible characterizations on a number of commercial remote sensing systems. Overall, this characterization software suite improves the reliability of ground-truth data processing techniques that are required for remote sensing system in-flight characterizations.

Stanley, Thomas↗
NASA NTRS1983

Application experience with the NASA aircraft interrogation and display system - A ground-support equipment for digital flight systems

The NASA Dryden Flight Research Facility has developed a microprocessor-based, user-programmable, general-purpose aircraft interrogation and display system (AIDS). The hardware and software of this ground-support equipment have been designed to permit diverse applications in support of aircraft digital flight-control systems and simulation facilities. AIDS is often employed to provide engineering-units display of internal digital system parameters during development and qualification testing. Such visibility into the system under test has proved to be a key element in the final qualification testing of aircraft digital flight-control systems. Three first-generation 8-bit units are now in service in support of several research aircraft projects, and user acceptance has been high. A second-generation design, extended AIDS (XAIDS), incorporating multiple 16-bit processors, is now being developed to support the forward swept wing aircraft project (X-29A). This paper outlines the AIDS concept, summarizes AIDS operational experience, and describes the planned XAIDS design and mechanization.

Glover, R. D.↗
NASA NTRS2007

WMAP C&DH Software

The command-and-data-handling (C&DH) software of the Wilkinson Microwave Anisotropy Probe (WMAP) spacecraft functions as the sole interface between (1) the spacecraft and its instrument subsystem and (2) ground operations equipment. This software includes a command-decoding and -distribution system, a telemetry/data-handling system, and a data-storage-and-playback system. This software performs onboard processing of attitude sensor data and generates commands for attitude-control actuators in a closed-loop fashion. It also processes stored commands and monitors health and safety functions for the spacecraft and its instrument subsystems. The basic functionality of this software is the same of that of the older C&DH software of the Rossi X-Ray Timing Explorer (RXTE) spacecraft, the main difference being the addition of the attitude-control functionality. Previously, the C&DH and attitude-control computations were performed by different processors because a single RXTE processor did not have enough processing power. The WMAP spacecraft includes a more-powerful processor capable of performing both computations.

Cudmore, Alan↗
NASA NTRS1984

Interplanetary navigation - An overview

The major elements of the Voyager navigational system are described, within the context of a general review of current interplanetary navigational techniques and equipment. The data processing components of the Voyager navigational system are described, including the ground-based computational facilities and software, and the different support functions. A block diagram of the ground based data processing system is presented. The development of VLBI techniques for a high-precision quasi-relative navigational system to be incorporated into the navigational payload of the Galileo satellite in 1986 is also discussed.

Jordan, J. F.↗
NASA NTRS1999

Calibration of the Geosar Dual Frequency Interferometric SAR

GeoSAR is an airborne, interferometric Synthetic Aperture Radar (INSAR) system for terrain mapping, currently under development by a consortium including NASA's Jet Propulsion Laboratory (JPL), Calgis, Inc., and the California Department of Conservation (CalDOC) with funding provided by the Topographic Engineering Center (TEC) of the U.S. Army Corps of Engineers and the Defense Advanced Research Projects Agency (DARPA). The radar simultaneously maps swaths on both sides of the aircraft at two frequencies, X-Band and P-Band. For the P-Band system, data is collected for two across track interferometric baselines and at the crossed polarization. The aircraft position and attitude are measured using two Honeywell Embedded GPS Inertial Navigation Units (EGI) and an Ashtech Z12 GPS receiver. The mechanical orientation and position of the antennas are actively measured using a Laser Baseline Metrology System (LBMS). In the GeoSAR motion measurement software, these data are optimally combined with data from a nearby ground station using Ashtech PNAV software to produce the position, orientation, and baseline information are used to process the dual frequency radar data. Proper calibration of the GeoSAR system is essential to obtaining digital elevation models (DEMS) with the required sub-meter level planimetric and vertical accuracies. Calibration begins with the determination of the yaw and pitch biases for the two EGI units. Common range delays are determined for each mode, along with differential time and phase delays between channels. Because the antennas are measured by the LBMS, baseline calibration consists primarily of measuring a constant offset between mechanical center and the electrical phase center of the antennas. A phase screen, an offset to the interferometric phase difference which is a function of absolute phase, is applied to the interferometric data to compensate for multipath and leakage. Calibration parameters are calculated for each of the ten processing modes, each of the operational bandwidths (80 and 160 MHZ), and each aircraft altitude. In this talk we will discuss the layout calibration sites, the synthesis of data from multiple flights to improve the calibration, methods for determining time and phase delays, and techniques for determining radiometric and polarimetric quantities. We will describe how calibration quantities are incorporated into the processor and pre-processor. We will demonstrate our techniques applied to GeoSar data and assess the stability and accuracy of the calibration. This will be compared to the modeled performance determined from calibrating the output of a point target simulator. The details of baseline determination and phase screen calculation are covered in related talks.

Chapine, Elaine↗