Wojtkowiak, H., Balagurin, O., Fellinger, G., Kayal, H.: ASAP: AUTONOMY THROUGH ON-BOARD PLANNING.6th International Conference on Recent Advances in Space Technologies (RAST). AIAA American Institute of Aeronautics and Astronautics (2013).
Usually a satellite is entirely controlled from ground. Its tasks are planned in advance by a satellite operations team using specialized scheduling software. When the orbiting satellite enters the transmission range of the ground station, communication is possible, and a newly generated plan (if required) can be uploaded and executed in due time. Although this approach is well-established and has been used for decades, it has some major drawbacks. It binds resources (e.g. personal staff, communication links, etc.) and prohibits fast reactions to transient events, due to the required change of the currently active plan. In the traditional approach, the changes can only be achieved by transmitting a new plan from the ground station to the satellite. This communication imposes time delays which are not acceptable for fast reactions and responses. A way to overcome this problem is to equip the satellite with an autonomous decision-making system which is able to alter the operation plan onboard the satellite. The department of Computer Science VIII of the University of Wuerzburg is currently developing such a system named ASAP and will present it in this paper. The focus lies on the interaction between ASAP and the OnBoard-Computer of the satellite.
Wojtkowiak, H., Balagurin, O., Fellinger, G., Kayal, H.: ASAP: AUTONOMOUS DYNAMIC SCHEDULING FOR SMALL SATELLITES.64th International Astronautical Congress. International Astronautical Federation (2013).
Usually planning of satellite missions is done on ground by an expert team. Activities have to be prioritized; telecommand lists have to be generated according to time-based procedures and sent to the satellite for execution. In consequence of this method expenses for operations are a major part of the overall satellite mission cost because of the usually intense involvement of humans in the planning and operations processes. Additionally, doing it this way makes it impossible to react on special short-time events such as volcanic eruptions or fires. To improve the process of mission planning, the development of a new autonomous imaging system with an integrated autonomous planning system has been started at the University of Wuerzburg which is funded through the German Aerospace Center (FKZ 50RM1208) by the Federal Ministry of Economics and Technology (BMWi). The aim is to use such a system on board of nano satellites in the future to enable autonomous fast time responses to short-lived optical phenomena. Furthermore the system can relieve the On-Board-Computer (OBC) of the satellite by providing scheduling capacities and mechanism. The main functionality of our new satellite system is twofold. On one hand, it uses its optical system to autonomously detect, classify and track (in the field of view) interesting objects or phenomena like meteors or lightning in the Earth´s atmosphere. In the context of our project, this is called “Autonomous Sensing (AS)”. On the other hand, it provides the capability and means to schedule satellite operation procedures. This feature is called “Autonomous Planning (AP)”. Combined, these acronyms form the project's name ASAP. The main feature is that both functionalities work autonomously. The focus of this paper lies on the scheduling system of ASAP. It has to manage activities and resources. One or several resources can be grouped to one hardware platform on which activities can be executed. Activities and resources can be distinguished in internal ones and external ones. Internal activities and resources are provided by ASAP and can be independently scheduled. For example the “Autonomous Sensing” functionality of ASAP is fully accomplished by internal activities and resources. External activities and resources can be registered in ASAP in order to be integrated into the scheduling process. This sort of operation requires some kind of communication. For this case ASAP offers a special interface to bind external components into the scheduling mechanism.
Wojtkowiak, H., Balagurin, O., Fellinger, G., Kayal, H.: ASAP: Increasing the autonomy of small satellites.9th IAA Symposium on Small Satellites for Earth Observation. International Academy of Astronautics (2013).
Fellinger, G., Dietrich, G., Fette, G., Kayal, H., Puppe, F., Schneider, V., Wojtkowiak, H.: ADIA: A Novel Onboard Failure Diagnostic System for Nanosatellites.64th International Astronautical Congress. International Astronautical Federation (2013).
Spacecraft failure analysis is often a time-consuming process which requires increased attention from ground personnel. Since operations expenditures represent a major part of overall satellite mission cost, efficient assignment of resources, especially when it comes to as weighty a cost factor as manpower, is critical. This is especially true for small-scale satellites which are often operated by research groups with limited means. Also, ground-based error source isolation by operators implies that due to limited contact windows, real-time diagnosis is usually out of the question, hence losing valuable time when quick reactions to critical failures are necessary. Moreover, the onset of failures looming for several days or weeks cannot be easily predicted by human operators who are by and large not good at trend-analyzing large amounts of data, especially if mutually interdependent time series are involved. Thus, the capability to analyze errors in real-time onboard a satellite is desirable as it can help cut costs and reduce mission failure risk. In order to provide such capabilities, the development of a new autonomous failure diagnostic system called ADIA (Autonomous Diagnostic System for Satellites) has started at the University of Würzburg which is funded through the German Aerospace Center (FKZ 50RM1231) by the Federal Ministry of Economics and Technology (BMWi). The goal is to develop an onboard diagnostic software which is capable of detecting errors, isolating them with respect to their cause as well as trend analysis of spacecraft telemetry data for the prediction of future subsystem malfunctions. The system consists of two functionally intertwined components. One is a set of diagnostic algorithms with an interface to the satellite’s TTC system. The second is a satellite simulator software which has two functions: on the one hand, it serves as a “telemetry generator” in the context of ADIA’s development process, providing the diagnostic core with raw data during system testing and fine-tuning. On the other hand, the simulator can itself be integrated into the diagnostic component, thus making ADIA a model-based analysis tool. Internal states of the simulator can be compared with the state of the actual satellite in order to derive hypotheses on the nature of an emerging error. The focus of this paper lies on the discussion of ADIA’s requirements, the basic functional concept as well as the workings of the diagnostic core. Additionally, a brief discussion of the nanosatellite to be modeled as part of the development process is included.
Freimann, A., Schmidt, M., Schilling, K., Graciano, J., Fellinger, G., Kayal, H., Spies, P., Zessin, H., Henkel, P., Gerhard, T., Reichel, F., Rummelhagen, M., Marszalek, M., Bollert, R.: The BayKoSM Project: Technologies for Swarm Missions.5th International Conference on Spacecraft Formation Flying Missions and Technologies. German Space Operations Center of DLR (2013).
The BayKoSM project is a cooperation of several universities and companies in Bavaria, funded by the Bavarian government. The aim of the project is the development of key technologies for swarms of mobile vehicles. These swarms consist of either pico satellites or uninhabited aerial vehicles (UAVs). The paper describes the corresponding technologies and how they are used within the scope of BayKoSM for intelligent swarm behavior.
