Together with the department „System Analysis Space Transport,“ the department „System Analysis Space Segment“ (SARA) forms the area of system analysis and thus it is integrated as one of three core areas in the DLR-Institute of Space Systems. The main task of the department is to analyse and evaluate existing and future space systems. This analysis and evaluation happens in terms of technical as well as economical and social aspects. The studies of SARA and the developments function as a preparation for activities in the field of system technology. SARA develops and uses qualitative and quantitative computer-based methods for the evaluation of space concepts concerning applicability, feasibility, acceptance, costs and benefit. Furthermore, these results are processed into decision guidance and recommendations for politics and policy objectives. National and European space flight shall thereby be further developed and managed in the long term. The German space position shall also be strengthened sustainably in the international competition.
The most important tool of SARA is the “Concurrent Engineering Facility” which has been in operation at DLR Bremen since 2009.
The department is divided into three main areas which are visualised in the following organisation chart:
System Analysis Space Segment
Concurrent- and Systems Engineering
Evaluation & Cost Estimation
System Analysis Satellites
The core element in the area of concurrent and systems engineering is the operation of the Concurrent Engineering Facility (CEF). In order to conduct system analysis efficiently and to follow the system conception of bundling subsystem knowledge sustainably, the new CEF has been up and running in Bremen since January 2009.
The CEF offers experts of different fields the opportunity to work collaboratively in a joint facility. It guarantees the efficiency-enhancing method of the concurrent engineering by using most modern tools and communication-technologies. The facility is primarily used for space studies in phase 0/A-level. Right now, the extension of the process to higher project phases is one of the main goals.
Concurrent Engineering is systems engineering technology for design, development and technical management described by
The process minimises errors and increases the consistency of designs especially in the starting phase of a project. Thus, it saves design costs and time over the entire product life cycle.
In terms of application and research in the field of systems engineering, the unit is also involved in projects on “Model-Based Systems Engineering” (MBSE) and in the enhancing of space vehicle design processes.
Technology Evaluation and System Analysis
Within technology evaluation (System Analysis) different methods are developed to evaluate space missions or space systems in terms of technical, economical and social criteria. By a focused system analysis, developing errors can be uncovered at an early stage and adequate measures can be taken.
From the Sputnik-Satellite (1957) to today, thousands of satellites have been sent into Earth orbit. The question here concerns the properties of the particular space vehicle subsystems. Are there connections in time or causalities in the technological development between the subsystems? Were there leaps in technology in the evolution of space vehicles? The goal of the technology evaluation/system analysis is the deduction of future space flight trends.
One of the most important tasks within the evaluation of space systems is cost analysis; however, there is a lack of technical and programmatic information in the early phase of a space project which complicates a meaningful cost analysis. For this reason, the parametric cost estimation method is increasingly used. So-called Cost Estimating Relationships (CER) are taken into account here. Next to the use of open-source cost models, EVACO also develops its own, DLR-intern cost model, which allows for the special circumstances of DLR. Besides the single cost models, general efficiency analyses are also created in this area. Evaluation methods which are used are among others:
Within these analysis we use the software think-cell, which is an add-in, helping to create complex diagrams such as Waterfall or Gantt models easily. For university or research purposes free licenses are available. Further information can be found on the think-cell website.
Within this area, different software tools are developed to support the Concurrent Engineering (CE) process. The Knowledge Management (KM) architecture S.P.O.C.K. (Software Platform for Organizing and Capturing Knowledge) has been developed as an essential support tool. The tool has been designed within an ESA order especially for the CE environment to support engineers and experts within the CEF in the conceptual design of space systems.
Another database that has been developed by the section EVACO deals with the parametric compilation of past space systems. This Concurrent Engineering Reference Database (CERD) comprises most of the technical and mission-specific parameters of a space vehicle. Using this database, important conclusions can be drawn by analogy between the developing space vehicle and past space systems concurrently to the CE design process. This reference database supports the engineers in their decisions, and the entire design process is accelerated.
In this area system and mission concepts are worked out, design-tasks are carried out on a subsystem level (e.g. structure, thermal, power, communication) and trades on e.g. accommodation, integration of instruments, budgets, operation and costs are worked out. To realize complemented studies the department networks with experts of other departments, institutes and externs, if needed. Furthermore, internationally known systems and visions are investigated and future possibilities for German and European space missions are analysed, whereas missing and existing competencies are outlined in the correspondent areas.
In the field of astronautics, analyses were conducted for a potential manned European space transport on the basis of the ATV-technology in terms of technical applicability and operational scenarios (BERT/ATV-Evolution). Furthermore, scenarios for exploration of Moon, Earth and sun are calculated. Therefore, the intensive collaboration with scientists and users was a key factor for successful study. Studies pertaining to the problem of climate change, i.e. detection of greenhouse gases satellite systems, were also analyzed. Additionally, the detailed mission analysis of AsteroidFinder/SSB Compact Satellite is supported.
Every space mission is exposed to the potential danger that micro-meteorites and space debris pose. To estimate the risks of space missions, simulation models (MASTER, ORDEM) were used in order to generate probabilities concerning space debris. The in situ verification of the analytical methods on orbital space debris environment is also part of the department.