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Contents Ablative Thermal Protection Systems
About thermal controlSpacecraft thermal controlWhat does thermal control do?
Space cryogenicsOverviewStirling and pulse tube coolersJoule Thomson coolersSub-kelvin coolersDensified propellantCryogenic composite tank and line
Heat transport technologiesOverviewCapillary-pumped two-phase heat transport technologyMechanically-pumped heat transport technology
Thermal protection systems
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Reusable Thermal Protection Systems and Hot Structures
Development of reusable European Thermal Protection Systems (TPS) and Hot Structures (HS) started back in the early 1990s during the days of the Hermes space-glider. After the cancellation of Hermes, considerable development on TPS&HS technologies continued through several ESA-programmes, particularly the Manned Space Transportation Program (MSTP) and the Future European Space Transportation Investigation Programme (FESTIP).
In the frame of the X-38 programme (NASA's planned precursor for a Crew Return Vehicle) at the end of the 1990s, major contributions to the vehicle TPS&HS were developed through ESA and national European space agencies. The X-38 programme led to the on-ground qualification of a large number of European TPS technologies. These included in particular ceramic elements based on C/SiC, applied as nose and panel TPS and as hot structure control surfaces (for the vehicle body flap) including the roller bearing assembly.
Roller bearing assembly
Further developments covered flexible TPS blankets for almost the entire vehicle leeward side and additional components, like internal insulations, high temperatures sealing systems and advanced attachment systems.
Flexible external insulation
In addition to the programmes mentioned, developments were and are performed in the frame of ESA's technology programmes, TRP and GSTP. In recent years the existing TPS technologies were further improved with a particular focus on an increased capability for multiple flights. In addition, intense development took place in the field of metallic TPS technologies.
Ceramic thermal protection system panel
Today continued TPS developments are driven by ESA's Future Launcher Preparatory Programme (FLPP) with the aim of an in-flight demonstration on the Intermediate Experimental Vehicle (IXV) planned to be flown in 2010.
IXV with heat fluxes
Ablative Thermal Protection Systems
Atmospheric Re-entry Demonstrator
While reusable TPS technologies are mainly focussed towards vehicles for multiple earth-entries (reusable launch vehicles or transfer vehicles to ISS), atmospheric entry probes for exploration mission mostly depend on ablative thermal protection systems. An impressive recent example is the Huygens probe which entered into Titan's atmosphere in January 2005. Future sample return mission (from e.g. Mars or comets) will involve a direct high-speed Earth entry leading to peak heat fluxes in the range of 10-20MW/m2, and will therefore require a highly robust TPS for the re-entry into the Earth atmosphere. Potential missions to explore the atmospheres of the large gas planets will be confronted with heat flux ranges which are still at the limits of today’s thermal protection systems.
Though no such mission is currently confirmed, there is a strong scientific interest and several feasibility studies were performed in recent years.
In 2005 ESA has initiated a European Ablation Working Group with the aim to improve visibility and dialogue in between the different institutes, industries and agencies working on the subject. An immediate particular objective of the working group is the improvement of existing numerical simulation codes and the establishment of common material databases.
Further technology development is planned for the next years in the field of ablative systems in order to prepare for the interesting and demanding missions currently under consideration.
Last update: 7 May 2007
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