Space vehicles are exposed to extreme thermal loads when entering a planetary atmosphere and in order to protect the vehicle’s interior a thermal protection system (TPS) is required. For state-of-the-art re-usable vehicles, as e.g. the Space Shuttle orbiter, the thermal management concept is mainly based on an indirect strategy making use of the fact that heat loads can be controlled by choosing an appropriate external shape for the vehicle and an adequate entry trajectory. A sophisticated technical thermal management is not established, thermal balances are applied only locally providing information about required insulation thicknesses corresponding to the local heat flux.
As a consequence, highly loaded vehicle components, as e.g. the nose and the leading edges of the wings, have a blunt shape. Aerodynamically the bluntness is a major drawback, because it significantly reduces the vehicle’s flight performance resulting in a very poor capability for fast corrections to the flight path by flying maneuvers.
For future space vehicles significant improvements are required in the long term in flight performance. Next generation orbiters and to a huge extent hypersonic transport vehicles will need fast flight path control for efficient operation, a requirement that cannot be met with extremely blunted components.
A significant reduction of bluntness, however, means significantly higher heat loads which are beyond the capabilities of the conventional thermal management concept. Future thermal management concepts will need to be defined globally with a technically sophisticated implementation in order to meet the requirements.
The THOR project will thematically focus on the development of new disruptive thermal management concepts which are specifically targeted to atmospheric entries of future space vehicles and hypersonic transport vehicles.
Two main options for dealing with severe thermal environments are considered:
- Passive cooling technologies, and
- Active cooling technologies.
Two separate thermal management concepts will be considered in detail for each option. Common to all considered concepts is a globalized approach in order to improve the thermal capabilities of TPS systems and to increase the maximal tolerable heat loads.
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