Session
Session I: Existing and Near Term Missions
Abstract
The first satellites at the beginning of the space age were small satellites. Primarily because of the fact that the launch capacity was small. Later on the launchers and satellites grew, and today a lot of big missions with a high complexity are in space. These missions serve the science, the military and defense, commercial and operational users as well as public and private interests. Today’s technology allows the supplement of the big missions by small satellite missions. By exploring new technologies and methods small satellites can prepare new experiments and technologies for big missions or solve complementary questions. Small satellites have several advantages, e. g. - extremely smaller budgets, - shorter development and manufacturing time, - more dedicated mission objectives, - smaller user communities, - implementation of new technologies with higher risks. Small satellites have to meet a big challenge: to answer high performance requirements by means of small equipment and especially of small budgets. Out of all aspects the cost aspect is one of the most important driver for small satellite missions. Usually, the largest part of the total mission costs are the spacecraft costs (user segment excluded). They will be followed by the launch cost (20-50 % of the total costs) and cost for ground segment including operations (up to 15 %) [1]. And of the spacecraft the attitude control system is usually the most expensive subsystem. This general experience with satellites is also valid for small satellites, for instance mini-satellites with a total mass up to 500 kg and micro-satellites with a total mass between 30 and about 130 kg. With regard to the mentioned cost drivers the group of the micro-satellites seems to be the most appropriate solution to fulfill the challenging mission objectives under lowbudget constraints because of: 1. feasibility of launch as piggy-back or as auxiliary payload (launch costs lower than for shared launch or dedicated launch – necessary for mini-satellites), 2. feasibility of high performance payloads for micro-satellites, 3. feasibility of high performance spacecraft busses. The suppositions 2 and 3 can be sufficiently accomplished under low-budget constraints only by using: - state-of-the-art technologies, - a mixed strategy in the definition of the quality level of the EEE parts and components, - a dedicated quality assurance plan, - a risc management system, - extensive redundancy strategies, - extensive tests especially on system level, - large designs margins (over-design), - robust design principles. To keep the costs within the low-budget frame (in comparison to big missions) the demonstration of new and not space2 qualified technologies for the spacecraft and especially for the attitude subsystem is one key point in fulfilling high performance mission requirements. Taking this into account the DLR micro-satellite mission BIRD has to demonstrate a high performance capability of spacecraft bus by using and testing new technologies basing on a mixed parts and components qualification level. The technology experiments of BIRD shall demonstrate the limits and the advantages of using new developed components, methods, algorithms and technologies.
Demonstration of Small Satellite Technologies by the Bird Mission
The first satellites at the beginning of the space age were small satellites. Primarily because of the fact that the launch capacity was small. Later on the launchers and satellites grew, and today a lot of big missions with a high complexity are in space. These missions serve the science, the military and defense, commercial and operational users as well as public and private interests. Today’s technology allows the supplement of the big missions by small satellite missions. By exploring new technologies and methods small satellites can prepare new experiments and technologies for big missions or solve complementary questions. Small satellites have several advantages, e. g. - extremely smaller budgets, - shorter development and manufacturing time, - more dedicated mission objectives, - smaller user communities, - implementation of new technologies with higher risks. Small satellites have to meet a big challenge: to answer high performance requirements by means of small equipment and especially of small budgets. Out of all aspects the cost aspect is one of the most important driver for small satellite missions. Usually, the largest part of the total mission costs are the spacecraft costs (user segment excluded). They will be followed by the launch cost (20-50 % of the total costs) and cost for ground segment including operations (up to 15 %) [1]. And of the spacecraft the attitude control system is usually the most expensive subsystem. This general experience with satellites is also valid for small satellites, for instance mini-satellites with a total mass up to 500 kg and micro-satellites with a total mass between 30 and about 130 kg. With regard to the mentioned cost drivers the group of the micro-satellites seems to be the most appropriate solution to fulfill the challenging mission objectives under lowbudget constraints because of: 1. feasibility of launch as piggy-back or as auxiliary payload (launch costs lower than for shared launch or dedicated launch – necessary for mini-satellites), 2. feasibility of high performance payloads for micro-satellites, 3. feasibility of high performance spacecraft busses. The suppositions 2 and 3 can be sufficiently accomplished under low-budget constraints only by using: - state-of-the-art technologies, - a mixed strategy in the definition of the quality level of the EEE parts and components, - a dedicated quality assurance plan, - a risc management system, - extensive redundancy strategies, - extensive tests especially on system level, - large designs margins (over-design), - robust design principles. To keep the costs within the low-budget frame (in comparison to big missions) the demonstration of new and not space2 qualified technologies for the spacecraft and especially for the attitude subsystem is one key point in fulfilling high performance mission requirements. Taking this into account the DLR micro-satellite mission BIRD has to demonstrate a high performance capability of spacecraft bus by using and testing new technologies basing on a mixed parts and components qualification level. The technology experiments of BIRD shall demonstrate the limits and the advantages of using new developed components, methods, algorithms and technologies.
