TINA - Knowledgebased Mission Planning ForFuture Spacecrafts And Their AutonomousOperation

The TINA Systems (TImeliNe Assistants) are a family of knowledgebased planning systems developed by Dornier Satellitensysteme GmbH. The first approaches to knowledgebased planning systems reach back to the eighties and cover the domain of satellite assembly planning, using rule based and Lisp based problem solving techniques. Over the years, these planning tools have evolved to a modular object oriented program library with the application domains of satellite assembly, integration and test as well as satellite mission operations. One common kernel includes the timeline generation algorithms and the inference and constraint propagation engine. A commercially available constraint propagation toolset is used as base and the entire application is implemented in the C++ language. Coupled hereto are a graphical X-Windows based user interface and domain specific numeric modules, such as e.g. an orbit propagation module for the mission planning application. The key feature, which makes the TINA Timeline Generator specially performant in complex problem solving domains, is the fact that it is neither a pure planning algorithm for implementation of logical PERT charts, nor a pure Scheduler (like a lot of PC based tools) for generating GANTT Timelines. TINA is a "Timeline Generator", a tool considering in an integrated timeline processing procedure both logical interdependencies of positioned activites as well as numeric constraints such as resource consumptions or interrelations of generated and consumed resources. This hybrid base technology also made TINA the appropriate choice for a recently completed study of the European Space Agency (ESA) which assessed the applicability of autonomous operation of earth observation satellites. Earth observation satellites today still require a full 24hr operated ground station and satellites with a near polar, highly inclined orbit additionally impose the complications that not at every orbit a ground station contact with mission product downlink and command uplink can be achieved. Severe operational inefficiencies occur, when during such an off-contact period errors occur during timeline execution onboard the satellite. To improve mission product availability and for assessment of a satellite operation with a ground station operated only during normal business hours, within this ESA study "Distributed Intelligence for Ground/Space Systems" an intelligent mission timeline generation, timeline uplink at ground contact and timeline regeneration onboard the satellite in case of problems has been assessed. Within this study an entirely new commanding concept for satellite payloads based on parameterized "user requests" has been developed and for the first time has been implemented in a timeline generation system.