Analysis of hydrogen nozzle flow with chemical non-equilibrium

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A comparison and some applications to non-steady cases

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A student project as part of an MSc curriculum: Delfi-C³

The Delfi-C3 is a university satellite of the Delft University of Technology. The project started in November 2004 and had a dual mission: (no bullets in abstract!)To offer at least 25 students as part of their Master of Science (MSc) study the opportunity to gain hands on experience on a real space project and to provide a platform for fast and low-cost technology qualification in space. The project was aiming for a launch in the first half of 2007. It was set up two faculties of Delft University of Technology in cooperation with industry partners. With over 60 students that worked on the project and a launch in April 2008, it can, already now, be concluded that the project was a success. The paper addresses lessons-learned from Delfi-C3 related to thesis supervision, hierarchy in the project and workforce discontinuity. Also from the side of the university some adaptations are required to enable an efficient, effective and qualitatively satisfactory execution of the project. These adaptations are related to the type of staff required, composition of the student team and, generally, “production-process-mindedness” of supporting university departments. And, may be most important, the student’s effort as a team member must be valued such that he or she may achieve the same appreciation as his or her fellow students working on an individual, theoretical MSc thesis subject.Space EngineeringAerospace Engineerin

Delfi?n3Xt Nanosatellite Subsystems: Buying, Outsourcing or Internal Development

This paper provides the results of a study of project management and systems engineering effectiveness regarding the allocation of work and procurement policy of a nanosatellite project. The Delfi-n3Xt nanosatellite is currently under development at Delft University of Technology (TU Delft) and will serve as a case study for this analysis. Delfi-n3Xt primary mission objectives are education, technology demonstration (payloads) and advancement of nanosatellite bus subsystems. For each (sub-) system of a satellite, there are in different option to allocate the work or to procure a certain (sub-) system. The criteria for choosing an option can be based on organizational, technical, political and social arguments. A selection of these examples is taken as a case study to provide insight in the rationale behind the choices. It is shown that trade-offs for work allocation or procurement policies are sensitive to different approaches and it is suggested that in many cases trade-offs might be flawed due to subjective manners which have not or will not be documented. It is finally stated that this might lead to problems and it is likely that this lack of transparency also take place in other space projects.Space EngineeringAerospace Engineerin

Does Systems Engineering in Space Projects Pay?

This paper attempts to answer the question whether it “pays” to apply Systems Engineering methods, tools and techniques within a space project. To this purpose a possible correlation has been investigated between the Systems Engineering effort applied within a number of space projects and the project result in terms of technical quality, cost and schedule. Use has been made of historical data derived from the results of Systems Engineering audits of projects, some recent audits performed along the same lines and assessments of project results in terms of technical quality, cost and schedule by the systems engineers involved in the projects. Basis for the audits is a checklist addressing 93 different aspects of Systems Engineering in the field of requirements, concept design, design & development, verification and technical management. In total nine data sets related to six projects in the industrial and the academic world were used. Although the data obtained are rather “noisy” there appears to be a clear positive correlation between the SE effort applied and the project result. It appears also that the positive effects mainly show up in the cost and schedule results of the project, the technical quality of the project result being generally of a rather satisfactory level. Examining the results in detail the Systems Engineering effort in the field of requirements, design & development and technical management has the strongest correlation with the project result. The effort in the field of (concept) design and verification shows a less strong correlation. The data have been “refined” by deleting the projects that were most strongly influencing the correlation in a positive sense. The overall results remained, however, the same. An overview is given of those aspects generally receiving little attention in the Systems Engineering effort. Further analysis of these results will be the subject of a follow-on study.Space EngineeringAerospace Engineerin

A comparative analysis of project management and systems engineering techniques in CubeSat projects

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SCALES: A System Level Tool for Conceptual Design of Nano- and Microsatellites

A satellite design tool has been developed offering systems engineers a fast way to analyze the feasibility of a particular design concept. The tool differs from available tools on the market in that it is specifically targeted at small satellites in the mass range of 1-50 kg, and with a limited development time. The tool is developed in Excel, and users interact with the tool in an intuitive manner through only one input and one output sheet. Required inputs include payload specifications, launcher characteristics, sensor & actuator types, and goal satellite mass, volume and power level. Outputs offered by the tool include mass, volume and power budgets, operating temperature envelope, attitude accuracy, propellant mass, transmit power and data rate. Algorithms, “rules-of thumb” and estimation relationships linking the input parameters with the output parameters have been based on models found in current literature, but have been revised and redefined based on an extensive satellite database containing over 200 satellites in the mass range of 0.1 – 50 kg, developed at Delft University of Technology.Space EngineeringAerospace Engineerin

Development of a System Level Tool for Conceptual Design of Small Satellites

The process of developing a tool aiming for conceptual design of nano- and microsatellites is described. The various challenges and derived solutions are discussed. The final product offers systems engineers a fast way to analyze the feasibility of a particular design concept. The tool differs from existing tools in that it is specifically targeted at small satellites in the mass range of 1-50 kg. It is developed in Excel, and users interact with the tool in an intuitive manner through only one input and one output sheet. Required inputs include external interactions with the system such as payload, mission orbit, launcher and ground station. A set of design choices are implemented to guide users with different background knowledge. These choices have impact on the resulting satellite mass and power budgets, operating temperature envelope, attitude accuracy, propellant mass, received transmit power and data rate. Algorithms and scaling rules linking the input with the output parameters have been based on existing material, but have been revised and redefined based on an extensive satellite database containing about 200 satellites in the mass range of 0.1 – 50 kg, developed at TU Delft.Space EngineeringAerospace Engineerin

Interface control procedures for university satellite programmes

Now that more and more universities have joined the CubeSat community and have their own satellite in Earth orbit, it is expected that the planned successors will be of higher complexity. These successors within a university satellite programme will often house more technically ad-vanced subsystems as well as more challenging technology demonstrations for external partners. Also, the number of these third-party experiments is expected to increase throughout the programme. In order to have successful projects, these developments ask for a robust and well-defined inter-face control approach. Interface control ensures the proper mutual development of satellite systems and coordination of simultaneously operating design teams. Well-defined and properly implemented interface control procedures prevent engineers from designing non-complying components that are unable to be correctly incorporated into the satellite. Redesigns are thereby less likely. The characteristics of university satellite projects ask for a different approach to systems engi-neering techniques than what is common within industry. This is attributable to a scarcity of resources, most notably manpower and budget. Considering these limitations, above all, inter-face control procedures have to be practically implementable. This paper proposes a set of interface control tools and procedures which are based on common industry practice, but scaled down for university satellite programmes. By elaborating on the proposed tools for interface control one should be able to set up an own set of tools, customized to its own project. Imple-mentation of the interface control tools and procedures is illustrated based on the Delfi-n3Xt satellite development of the Delft University of Technology where the procedures are currently in place.Space EngineeringAerospace Engineerin