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At least 109 records · Page 6

Architecture-Based Unit Testing of the Flight Software Product Line

This paper presents an analysis of the unit testing approach developed and used by the Core Flight Software (CFS) product line team at the NASA GSFC. The goal of the analysis is to understand, review, and reconunend strategies for improving the existing unit testing infrastructure as well as to capture lessons learned and best practices that can be used by other product line teams for their unit testing. The CFS unit testing framework is designed and implemented as a set of variation points, and thus testing support is built into the product line architecture. The analysis found that the CFS unit testing approach has many practical and good solutions that are worth considering when deciding how to design the testing architecture for a product line, which are documented in this paper along with some suggested innprovennents.

Ganesan, Dharmalingam

Perspectives on NASA flight software development - Apollo, Shuttle, Space Station

Flight data systems' software development is chronicled for the period encompassing NASA's Apollo, Space Shuttle, and (ongoing) Space Station Freedom programs, with attention to the methodologies and 'development tools' employed in each case and their mutual relationships. A dominant concern in all three programs has been the accommodation of software change; it has also been noted that any such long-term program carries the additional challenge of identifying which elements of its software-related 'institutional memory' are most critical, in order to preclude their loss through the retirement, promotion, or transfer of its 'last expert'.

Garman, John R.

Independent verification and validation for Space Shuttle flight software

The Committee for Review of Oversight Mechanisms for Space Shuttle Software was asked by the National Aeronautics and Space Administration's (NASA) Office of Space Flight to determine the need to continue independent verification and validation (IV&V) for Space Shuttle flight software. The Committee found that the current IV&V process is necessary to maintain NASA's stringent safety and quality requirements for man-rated vehicles. Therefore, the Committee does not support NASA's plan to eliminate funding for the IV&V effort in fiscal year 1993. The Committee believes that the Space Shuttle software development process is not adequate without IV&V and that elimination of IV&V as currently practiced will adversely affect the overall quality and safety of the software, both now and in the future. Furthermore, the Committee was told that no organization within NASA has the expertise or the manpower to replace the current IV&V function in a timely fashion, nor will building this expertise elsewhere necessarily reduce cost. Thus, the Committee does not recommend moving IV&V functions to other organizations within NASA unless the current IV&V is maintained for as long as it takes to build comparable expertise in the replacing organization.

Source record

Flight software issues in onboard automated planning: lessons learned on EO-1

This paper focuses on the onboard planner and scheduler CASPER, whose core planning engine is based on the ground system ASPEN. Given the challenges of developing flight software, we discuss several of the issues encountered in preparing the planner for flight, including reducing the code image size, determining what data to place within the engineering telemetry packet, and performing long term planning.

planning

MUST - An integrated system of support tools for research flight software engineering

The objectives of NASA's MUST (Multipurpose User-oriented Software Technology) program at Langley Research Center are to cut the cost of producing software which effectively utilizes digital systems for flight research. These objectives will be accomplished by providing an integrated system of support software tools for use throughout the research flight software development process. A description of the overall MUST program and its progress toward the release of a first MUST system will be presented. This release includes: a special interactive user interface, a library of subroutines, assemblers, a compiler, automatic documentation tools, and a test and simulation system.

Straeter, T. A.

The analysis of the statistical and historical information gathered during the development of the Shuttle Orbiter Primary Flight Software

The results of an effort to thoroughly and objectively analyze the statistical and historical information gathered during the development of the Shuttle Orbiter Primary Flight Software are given. The particular areas of interest include cost of the software, reliability of the software, requirements for the software and how the requirements changed during development of the system. Data related to the current version of the software system produced some interesting results. Suggestions are made for the saving of additional data which will allow additional investigation.

Simmons, D. B.

Flight software requirements and design support system

The desirability and feasibility of computer-augmented support for the pre-implementation activities occurring during the development of flight control software was investigated. The specific topics to be investigated were the capabilities to be included in a pre-implementation support system for flight control software system development, and the specification of a preliminary design for such a system. Further, the pre-implementation support system was to be characterized and specified under the constraints that it: (1) support both description and assessment of flight control software requirements definitions and design specification; (2) account for known software description and assessment techniques; (3) be compatible with existing and planned NASA flight control software development support system; and (4) does not impose, but may encourage, specific development technologies. An overview of the results is given.

Riddle, W. E.

Reusable, extendible flight software for a planetary spacecraft prototype testbed

As part of the 'Faster, Better, Cheaper' paradigm for NASA missions, the Jet Propulsion Laboratory (JPL) is developing a Flight System Testbed for prototyping and early integration of future planetary missions. This paper describes the development of a set of reusable, extendible spacecraft flight software to be used as a basis for prototypes in the testbed. This effort has focused on identification and implementation of functions which are common across multiple missions. This effort has also developed an intertask messaging system which supports modification of existing functions, additions of new functions, and porting to various computation and input/output (I/O) architectures. This paper also identifies a number of other JPL activities which support standardization and reusability of planetary spacecraft designs.

Krasner, Sanford M.

Accelerating NASA GN&C Flight Software Development

When the guidance, navigation, and control (GN&C) system for the Orion crew vehicle undergoes Critical Design Review (CDR), more than 90% of the flight software will already be developed - a first for NASA on a project of this scope and complexity. This achievement is due in large part to a new development approach using Model-Based Design.

Tamblyn, Scott

An Alternative Flight Software Paradigm: Applying Multivariate Logistic Regression to Sense Trigger Conditions using Inaccurate or Scarce Information

In late 2014, NASA will fly the Orion capsule on a Delta IV-Heavy rocket for the Exploration Flight Test-1 (EFT-1) mission. For EFT-1, the Orion capsule will be flying with a new GPS receiver and new navigation software. Given the experimental nature of the flight, the flight software must be robust to the loss of GPS measurements. Once the high-speed entry is complete, the drogue parachutes must be deployed within the proper conditions to stabilize the vehicle prior to deploying the main parachutes. When GPS is available in nominal operations, the vehicle will deploy the drogue parachutes based on an altitude trigger. However, when GPS is unavailable, the navigated altitude errors become excessively large, driving the need for a backup barometric altimeter to improve altitude knowledge. In order to increase overall robustness, the vehicle also has an alternate method of triggering the parachute deployment sequence based on planet-relative velocity if both the GPS and the barometric altimeter fail. However, this backup trigger results in large altitude errors relative to the targeted altitude. Motivated by this challenge, this paper demonstrates how logistic regression may be employed to semi-automatically generate robust triggers based on statistical analysis. Logistic regression is used as a ground processor pre-flight to develop a statistical classifier. The classifier would then be implemented in flight software and executed in real-time. This technique offers improved performance even in the face of highly inaccurate measurements. Although the logistic regression-based trigger approach will not be implemented within EFT-1 flight software, the methodology can be carried forward for future missions and vehicles

Smith, Kelly

An Alternative Flight Software Trigger Paradigm: Applying Multivariate Logistic Regression to Sense Trigger Conditions using Inaccurate or Scarce Information

In late 2014, NASA will fly the Orion capsule on a Delta IV-Heavy rocket for the Exploration Flight Test-1 (EFT-1) mission. For EFT-1, the Orion capsule will be flying with a new GPS receiver and new navigation software. Given the experimental nature of the flight, the flight software must be robust to the loss of GPS measurements. Once the high-speed entry is complete, the drogue parachutes must be deployed within the proper conditions to stabilize the vehicle prior to deploying the main parachutes. When GPS is available in nominal operations, the vehicle will deploy the drogue parachutes based on an altitude trigger. However, when GPS is unavailable, the navigated altitude errors become excessively large, driving the need for a backup barometric altimeter. In order to increase overall robustness, the vehicle also has an alternate method of triggering the drogue parachute deployment based on planet-relative velocity if both the GPS and the barometric altimeter fail. However, this velocity-based trigger results in large altitude errors relative to the targeted altitude. Motivated by this challenge, this paper demonstrates how logistic regression may be employed to automatically generate robust triggers based on statistical analysis. Logistic regression is used as a ground processor pre-flight to develop a classifier. The classifier would then be implemented in flight software and executed in real-time. This technique offers excellent performance even in the face of highly inaccurate measurements. Although the logistic regression-based trigger approach will not be implemented within EFT-1 flight software, the methodology can be carried forward for future missions and vehicles.

Smith, Kelly M.

An Alternative Flight Software Trigger Paradigm: Applying Multivariate Logistic Regression to Sense Trigger Conditions Using Inaccurate or Scarce Information

In late 2014, NASA will fly the Orion capsule on a Delta IV-Heavy rocket for the Exploration Flight Test-1 (EFT-1) mission. For EFT-1, the Orion capsule will be flying with a new GPS receiver and new navigation software. Given the experimental nature of the flight, the flight software must be robust to the loss of GPS measurements. Once the high-speed entry is complete, the drogue parachutes must be deployed within the proper conditions to stabilize the vehicle prior to deploying the main parachutes. When GPS is available in nominal operations, the vehicle will deploy the drogue parachutes based on an altitude trigger. However, when GPS is unavailable, the navigated altitude errors become excessively large, driving the need for a backup barometric altimeter to improve altitude knowledge. In order to increase overall robustness, the vehicle also has an alternate method of triggering the parachute deployment sequence based on planet-relative velocity if both the GPS and the barometric altimeter fail. However, this backup trigger results in large altitude errors relative to the targeted altitude. Motivated by this challenge, this paper demonstrates how logistic regression may be employed to semi-automatically generate robust triggers based on statistical analysis. Logistic regression is used as a ground processor pre-flight to develop a statistical classifier. The classifier would then be implemented in flight software and executed in real-time. This technique offers improved performance even in the face of highly inaccurate measurements. Although the logistic regression-based trigger approach will not be implemented within EFT-1 flight software, the methodology can be carried forward for future missions and vehicles.

Smith, Kelly M.

Quality Attributes for Mission Flight Software: A Reference for Architects

In the international standards for architecture descriptions in systems and software engineering (ISO/IEC/IEEE 42010), "concern" is a primary concept that often manifests itself in relation to the quality attributes or "ilities" that a system is expected to exhibit - qualities such as reliability, security and modifiability. One of the main uses of an architecture description is to serve as a basis for analyzing how well the architecture achieves its quality attributes, and that requires architects to be as precise as possible about what they mean in claiming, for example, that an architecture supports "modifiability." This paper describes a table, generated by NASA's Software Architecture Review Board, which lists fourteen key quality attributes, identifies different important aspects of each quality attribute and considers each aspect in terms of requirements, rationale, evidence, and tactics to achieve the aspect. This quality attribute table is intended to serve as a guide to software architects, software developers, and software architecture reviewers in the domain of mission-critical real-time embedded systems, such as space mission flight software.

Software architecture

Mars Science Laboratory Flight Software Internal Testing

The Mars Science Laboratory (MSL) team is sending the rover, Curiosity, to Mars, and therefore is physically and technically complex. During my stay, I have assisted the MSL Flight Software (FSW) team in implementing functional test scripts to ensure that the FSW performs to the best of its abilities. There are a large number of FSW requirements that have been written up for implementation; however I have only been assigned a few sections of these requirements. There are many stages within testing; one of the early stages is FSW Internal Testing (FIT). The FIT team can accomplish this with simulation software and the MSL Test Automation Kit (MTAK). MTAK has the ability to integrate with the Software Simulation Equipment (SSE) and the Mission Processing and Control System (MPCS) software which makes it a powerful tool within the MSL FSW development process. The MSL team must ensure that the rover accomplishes all stages of the mission successfully. Due to the natural complexity of this project there is a strong emphasis on testing, as failure is not an option. The entire mission could be jeopardized if something is overlooked.

entry, descent, and landing (EDL)

Advanced Resistive Exercise Device (ARED) Flight Software (FSW): A Unique Approach to Exercise in Long Duration Habitats

ARED flight instrumentation software is associated with an overall custom designed resistive exercise system that will be deployed on the International Space Station (ISS). This innovative software application fuses together many diverse and new technologies into a robust and usable package. The software takes advantage of touchscreen user interface technology by providing a graphical user interface on a Windows based tablet PC, meeting a design constraint of keyboard-less interaction with flight crewmembers. The software interacts with modified commercial data acquisition (DAQ) hardware to acquire multiple channels of sensor measurment from the ARED device. This information is recorded on the tablet PC and made available, via International Space Station (ISS) Wireless LAN (WLAN) and telemetry subsystems, to ground based mission medics and trainers for analysis. The software includes a feature to accept electronically encoded prescriptions of exercises that guide crewmembers through a customized regimen of resistive weight training, based on personal analysis. These electronically encoded prescriptions are provided to the crew via ISS WLAN and telemetry subsystems. All personal data is securely associated with an individual crew member, based on a PIN ID mechanism.

Mangieri, Mark

NASA Class A Certification of Core Flight Software (cFS)

NASA Gateway program has named cFS as the software architecture for the vehicle. The core CFS team (GSFC+JSC) is tasked to develop a certifiable release of the cFS bundle, by components, as class A, safety-critical flight software. It is to be available to all Gateway software developers, including our element vendors and international partners. Its availability & usage will be as stated by the Gateway User Agreement license. In this presentation, we will describe our general certification process, and more importantly, our certification artifacts that can be re-run to certify cFS on different platforms. Our goal is to also make available these certifiable packages to the open source community, specifically for cFE, OSAL and certain cFS applications and libraries that are currently hosted on NASA github (https://github.com/nasa).

Tam M Ngo

NASA Class A Certification of Core Flight Software (cFS)

NASA Gateway program has named cFS as the software architecture for the vehicle. The core CFS team (GSFC+JSC) is tasked to develop a certifiable release of the cFS bundle, by components, as class A, safety-critical flight software. It is to be available to all Gateway software developers, including our element vendors and international partners. Its availability & usage will be as stated by the Gateway User Agreement license. In this presentation, we will describe our general certification process, and more importantly, our certification artifacts that can be re-run to certify cFS on different platforms. Our goal is to also make available these certifiable packages to the open source community, specifically for cFE, OSAL and certain cFS applications and libraries that are currently hosted on NASA github (https://github.com/nasa).

Tam M Ngo