The cleanroom case study in the Software Engineering Laboratory: Project description and early analysis

This case study analyzes the application of the cleanroom software development methodology to the development of production software at the NASA/Goddard Space Flight Center. The cleanroom methodology emphasizes human discipline in program verification to produce reliable software products that are right the first time. Preliminary analysis of the cleanroom case study shows that the method can be applied successfully in the FDD environment and may increase staff productivity and product quality. Compared to typical Software Engineering Laboratory (SEL) activities, there is evidence of lower failure rates, a more complete and consistent set of inline code documentation, a different distribution of phase effort activity, and a different growth profile in terms of lines of code developed. The major goals of the study were to: (1) assess the process used in the SEL cleanroom model with respect to team structure, team activities, and effort distribution; (2) analyze the products of the SEL cleanroom model and determine the impact on measures of interest, including reliability, productivity, overall life-cycle cost, and software quality; and (3) analyze the residual products in the application of the SEL cleanroom model, such as fault distribution, error characteristics, system growth, and computer usage

NASA/DoD University Nano-Satellites for Distributed Spacecraft Control

Commonly referred to as \u27virtual platforms\u27, \u27formation flying\u27, \u27virtual spacecraft\u27, the implementation of Distributed Spacecraft Control technologies is being aggressively pursued internal and external of the National Aeronautics and Space Administration (NASA). Distributed spacecraft control architectures are characterized by interactions between spacecraft, cooperation between spacecraft, and common behavior among spacecraft within a constellation or formation. Collectively, these attributes enable a distributed network of individual spacecraft to act collaboratively as a single functional unit that exhibits a common system wide capability. Such capabilities will usher in the next generation of NASA Earth and Space science missions through the exploitation of new vantage points, the development of new sensing strategies and revolutionary measurement concepts, and the implementation of system-wide techniques which promote agility, adaptability, the ability to evolve over time, scalability, and affordability within mission concepts. A broad set of technology products is required to address the challenges presented within distributed spacecraft control architectures. Several technology development programs sponsored by NASA and the Department of Defense (DoD) have been or are now supporting efforts to develop these products. Building off the individual technology development programs and the foundations laid, DoD and NASA are teaming with one another to address common challenges, take advantage of the resources and opportunities available, and expedite the development and subsequent infusion of distributed spacecraft control technologies. The DoD University Nano-Satellite Program is serving as a focal point for such collaborative efforts

Promoting Real-Time Science in the Classroom using Wireless PDA Technology

The year is 2004, NASA has landed and deployed a fleet of rovers on the surface of Mars to continue the exploration of that planet and prepare the way for human visitors. Middle school students at Milton Elementary have been following the mission through the media and Internet as part of Mr. Johnson's Earth and space sciences class. The kids have been working in teams to track the rovers as they move across the surface of Mars on a scale model of the landing site they built from sand and rocks using pictures and video downloaded from the Internet. They also built their own version of a rover that can be driven around the model. The time is 3:36pm. Jim and a couple of his fellow students from class are sitting in the cafeteria waiting for a student council meeting to begin. Mary and several others are on the bus riding home. Kathy is in her father's car waiting to leave the parking lot. On Mars, Rover-3 has just stopped and issued an alert to ground control at NASA's Jet Propulsion Laboratory (JPL). Back at Milton Elementary chimes can be heard going off in the cafeteria, on the school bus, and in Kathy's car. The students are familiar with the drill and each brings up the Mars mission status display on their hand-held PDA device. They've been using their PDAs (those Palm devices that seem to be everywhere today) to obtain real-time position information for each of the rovers throughout the mission. The mission status display tells them that Rover-3 has stopped on the edge of a small gully and isn't quite sure what to do. The students begin considering the options amongst themselves. Should the rover just drive through the gully? If it does, what happens if it gets stuck? Maybe it should turnaround and look for away around the gully? Trough questions. Real questions. Real problems. The students know they will need to be prepared to discuss the options and conduct their own simulations using the models they built in Mr. Johnson's class tomorrow. Much the same way engineers and scientists will be working to solve the problem at NASA. It's a couple of days later, NASA has made a decision on what to do and has issued new commands for Rover-3 to execute at 9:15am Milton Elementary time. Interestingly, NASA's solution to the problem differs from the one favored by the students. 9:16am, chimes can be heard going off throughout Milton Elementary

Orion: A Low-Cost Demonstration of Formation Flying in Space Using GPS

This paper describes research on the design of a GPS based relative position and attitude sensing mission called Orion. The current Orion design consists of a #eet of 6 micro-satellites launched simultaneously into low Earth orbit to demonstrate coordinated attitude control, relativenavigation and control, and formation initialization techniques in space. This approach represents a new systems architecture that provides many performance and operations advantages, such as reduced operating cost, enhanced mission #exibility, and improved science observations. Akey objective of Orion is to demonstrate CarrierPhase Di#erential GPS #CDGPS# techniques to autonomously track the relative position and attitude between several spacecraft. Based on a research program focused on low-cost spacecraft design, Orion represents a critical step towards the realization of formation #ying and virtual platform capabilities