FP7/SPACE PROJECT “HYDRA” Hybrid Ablative Development For ReEntry In Planetary Atmospheric Thermal Protection
J. Barcena1, S. Florez1, B. Perez1, J-M. Bouilly2, G. Pinaud2, W. P. P. Fischer3, A. de Montbrun4, M.
Descomps4, D. Lorrain4, C. Zuber5, W. Rotaermel5 and H. Hald5, P. Portela6, K. Mergia7, G. Vekinis7,
A. Stefan8, C. Ban8, D. Bernard9, V. Leroy9, R. Wernitz10, A. Preci10 and G. Herdrich10
1Tecnalia
Research & Innovation, 2Astrium SAS (France), 3Astrium GmbH(Germany), 4 Lièges HPK SA (France), 5DLR
(Germany), 6High Performance Structures – HPS (Portugal), 7N.C.S.R "Demokritos" (Greece), 8INCAS (Romania),
9ICMCB-CNRS (France), 10IRS – University of Stuttgart (Germany
The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013)
under grant agreement n° 283797
OUTLINE
 INTRODUCTION AND MOTIVATION
 CONCEPT OF THE PROJECT
 CONSORTIUM, SCHEDULE AND WPs LOGIC
 MISSION REVIEW AND TPS SPECIFICATIONS
 MATERIALS STATE OF THE ART AND TRADE-OFF
 MATERIALS SELECTION AND PROCUREMENT
 BONDING & TPS ASSEMBLY
 SIMULATION AND TPS DESIGN
 CHARACTERISATION & VERIFICATION PLAN
 SUMARY AND MAIN CONCLUSIONS
 ACKNOWNLEDMENTS
08-04-2013 / 2
INTRODUCTION AND MOTIVATION
08-04-2013 / 3

Original approaches based on ablative materials and novel TPS solutions are required for space
applications where resistance in extreme oxidative environments and high temperatures are required.
The atmospheric entry of space vehicles from high-energy trajectories requires high-performance
thermal protection systems that can withstand extreme heat loads.

A new scenario has appeared due to a worldwide change in space mission planning strategies with entry
vehicles going back to capsule designs and ablators are re-gaining attention.

Consequently, the development of new, more efficient materials and systems is a must. Such
developments, nevertheless, have to be subject to extensive experimental investigations using suitable
facilities. In this view, the investigation and development of new materials based on ablative and
thermostructural concepts is crucial. A new (hybrid) concept based on the combination of both type of
TPS materials is proposed.

The advantage of the ceramic for this function is the low density compared to ablative material and
the excellent thermal performance in this heat load range, as well as the stability of the shape of TPS
which is an advantage for the aerodynamic of the re-entry vehicle.

Another asset comes from the reliability and safety point of view. The underneath ceramic core
offers extra thermal protection in case of the failure or underestimated design of the ablative external
protections (see reference of the Galieo’s Probe). An accompanying effect is also the lower
contamination during all mission phases and especially during re-entry.
CONCEPT OF THE PROJECT
08-04-2013 / 4

The concept of the project is based on the development of a novel hybrid heatshield, based on the
integration of an external ablative parts with a CMC thermostructural core. This will be carried out
by the integration of dissimilar materials.

The main advantage of a hybrid TPS heat-shield is based on the capability of the ablative layer of the
hybrid TPS of bearing higher heat loads than the ceramic layer underneath.
Ablative external shield
Joining region & Interface
CMC core

The main challenge is to achieve a sound bonding among the two parts. This will be carried-out by
advanced bonding technologies. This will be carried out by the study and development of new adhesives
solutions, with improved mechanical and insulating characteristics. The use of advanced high
temperature adhesives and hybrid solutions in combination with mechanical attachments will be
assessed, as well as other existing hybrid solutions.
CONCEPT OF THE PROJECT
Ablative based re-entry
08-04-2013 / 5
CMC based re-entry
Heatflux
Heatfluxpeak,
Interfacetemp,
limit 1200 ºC
T (sec)
Timeablative full burn-out

From this point of view it will offer improved mechanical properties as well as higher robustness
during the entry. Besides, the new moon or interplanetary missions planned cause higher heat loads
during earth re-entry than ceramic or metallic TPS can withstand, since these heat loads are characterized
by a peak profile the ablator can bear the high heat loads during the peak. For that a comparatively
thin layer of ablative material is sufficient. The large integral loads will then be overtaken by the
ablative/ceramic interfacial layer.
CONSORTIUM
08-04-2013 / 6
 CONSORTIUM MEMBERS LOCATION
The core group of HYDRA project is composed of
10 public and private organisations coming from 5
different European countries: France, Greece,
Germany, Romania and Spain.
2 – ASTRIUM-G
5 – DLR
8 – INCAS
3 – ASTRIUM-F
1 - TECNALIA
(Coordinator)
10 – IRS
6 – HPS
4 – HPK
9 – ICMCB
7 – DEMOKRITOS
CONSORTIUM
Part.No.
Part. Short
Name
08-04-2013 / 7
Profile
Relevant expertise for the project
Role in the project
Coordination, materials
developer, materials joining,
centre in charge of
dissemination actions.
1
TECNALIA
Research centre
Ceramic
composite
materials
design,
processing, bonding terisation. Background
on disseminations and technology transfer.
2
ASTRIUM-G
End user, large company,
large system integrator
CMC material development, design, analysis,
manufacturing & flight/ground testing as well
as application
Developing, designing,
manufacturing and
characterization testing of C/SiC
CMC's.
Mission specification, Material
developer and producer,
heatshield analysis
WPs Involvement
WP2, WP5, WP8, WP9.
Technical coordination in
(WP1, WP3, WP4, WP6,
Wp7)
WP4, WP8
3
ASTRIUM-F
End user, large company
Knowledge of management of atmospheric
entry programs. Competence in heatshield
thermal protection materials : development,
production, characterisation, modelling and
analysis
4
HPK
SME, material supplier
Cork composite materials (formulations and
manufacturing), tooling, bonding, moulding
and prototyping
Ablative cork materials and TPS
breadboard part supplier.
WP3, WP8
5
DLR
Research centre, space
systems manufacturer,
DLR is the German space agency. CMC
material development and charactersiation
Developing, designing,
manufacturing and
characterization testing of C/CSiC CMC's. Characterisation of
hybrid joints.
WP4, WP5, WP6, WP7,
WP8
6
HPS
SME, technology provider
TPS technology provider. Konow-how on
materials selection.
Technology advisory.
Engineering consulting.
WP2, WP5, WP6, WP7,
WP8
7
NCSRD
Research centre
Ablative-ceramic joining. Ceramic composite
materials characterization & coatings.
Materials joining and
characterization.
WP3, WP4, WP5, WP7,
WP8.
Characterisation of space
materials
WP1, WP3, WP6, WP8
8
INCAS
Research centre
Composite materials CFRP, C-C composite
and partially ceramic matrix design,
processing, thermo-mechanical
characterisation and morfostructural
investigation
9
ICMCB
Research centre
Numerical modeling of coupled phenomenon
occurring at local scale, 3D imaging of multi
materials
Modelling and characterisation
WP6, WP7, WP8
10
IRS
University
Characterisation of TPS comments and hot
structures.
Ground re-entry characterisation
and validation of the technology
sample
WP1, WP7, WP8
WP7, WP8
WORKPACKAGE: STUDY LOGIC
08-04-2013 / 8
WP1
Mission Profile & TPS specs
WP2
WP4
Structural Ceramic Core
WP5
Full TPS assembly
WP6
Modeling, Simulation and Design
WP7
Charac., Re-entry test & Validation
RTD
MANAGEMENT
OTHER
WP9
WP8
WP3
Ablative Protection Shield
Financial Management
Use, Explotaition & Dissemination
SoA & Materials Trade-off
SCHEDULE STATUS
February 2015
January 2015
December 2014
November 2014
October 2014
September 2014
August 2014
July 2014
June 2014
May 2014
April 2014
March 2014
February 2014
January 2014
December 2013
November 2013
October 2013
Year 3
September 2013
August 2013
July 2013
June 2013
May 2013
April 2013
March 2013
February 2013
January 2013
December 2012
November 2012
October 2012
Year 2
September 2012
August 2012
July 2012
June 2012
May 2012
April 2012
March 2012
WP No.
WP1 Mission review, trade-off, selection and TPS specs
WP1.1 Mission Profile
WP1.2 TPS specifications
WP2 State-of-the-art & Materials trade-off
WP2.1 State-of-the-art
WP2.2 Materials trade-off
WP3 Ablative protection shield
WP3.1 Advanced ablative materials based on resins
WP3.2 Advanced ablative materials based on cork
WP3.3 Manufacture of heat-shield parts
WP4 Stuctural ceramic core
WP4.1 Ceramic core development & characterization
WP4.2 Ceramic core concept verification & demonst.
WP5 Full protection system assembly
WP5.1 Definition of bonding processes
WP5.2 Ablative/ceramic frames joining
WP5.3 Fabrication of TPS breadboard
WP5.4. Testing & characterisation of the joint
WP6 Modelling, simulation & TPS design
WP6.1 Simulation of the oxidation
WP6.2 Hybrid thermal modelling of the hybrid concept
WP6.3 TPS final design
WP7 Characterisation, re-entry and validation
WP7.1 Microstructural and Thermo-mechanical chara.
WP7.2 Re-entry testing
WP7.3 Validation of the envisaged TPS concept
WP8 Use, exploitation and dissemination
WP8.1 Dissemination activities plan
WP8.2 Use plan
WP9 Financial management, coord. and reporting
WP9.1 Administrative
WP9.2 Financial
February 2012
Year 1
08-04-2013 / 9
M1
M2
M3
M4
M5
M6
M7
M8
Status
at
M13
MATERIALS TESTING & CHARACTERISATION PLAN
MANUFACTURE
WP3 & WP4
AST-F Manufacture of
10 ASTERM plates
(550 x 550 x 70 mm)
HPK Manufacture of 10
NORCOAT LIEGES
plates
(550 x 550 x 70 mm)
AST-G Manufacture of
SICARBON samples
1 m2 in different
pannels, 5mm
DLR Manufacture of CC/SiC samples
1 m2 in different
pannels, 5mm
ASSEMBLY
WP5
NCRSD
Additional testing & surface treatments
(K. Mergia)
Ablative-ablative interfaces (G. Veknis)
08-04-2013 / 10
CHARACTERISATION
WP7
ICMCB - Thermal Characterisation:
Only ablators
Laser Flash (RT - 1100)
Linear Dilatometry (RT-1600 ºC).
(No. samples & Dimension TBD)
NCRSD
Neutron Tomography
20 samples, Ø 40 x 40 mm aprox
(special assembly). Before and
after PWT
TECNALIA
•Materials machining
•Basic Thermal & Mechanical Characterisation
•Gluing & Joining
• Materials & Breadboard store
HPK
“in-situ” Cork Composite
manufacture on top of a
CMC plate
INCAS – Thermo-mechanical:
Compression & Flexural (RT)
Thermal shock QST2 (RT-1500 ºC)
Microstructural study
< 75 samples & 30 x 50 x 10 mm
DLR
Thermo-mechanical at
INDUTHERM facility (RT-2000ºC)
X-Ray tomography
45 sa mples - 60x 60 x 60
IRS
Plasma Wind Tunnel.
20 samples, Ø 39.8 x 40 mm aprox
(special assembly)
Emissivity (few samples are possible)
MISSION REVIEW AND TPS SPECIFICATIONS
08-04-2013 / 11
 Mission review and trade-off (by Astrium SAS): analysis of the current mission and
European roadmaps for planetary re-entry
MISSION REVIEW AND TPS SPECIFICATIONS
08-04-2013 / 12
 Final selection based on Earth re-entry: CSTS (from Low lunar orbit) and CTV/ARV (from
ISS)
CTV/ ARV (Credit Astrium SAS)
CSTS (Credit Astrium GmbH)
MISSION REVIEW AND TPS SPECIFICATIONS
08-04-2013 / 13
CTV/ARV (CREW TRANSFER VEHICLE / ADVANCED RE-ENTRY VEHICLE)
Control Points
Heatflux evolution
Local stagnation pressure
Heat-flux vs. Local stagnation pressure
MISSION REVIEW AND TPS SPECIFICATIONS
08-04-2013 / 14
CSTS (CREW SPACE TRANSPORTATION SYSTEM)
Control Points
Heatflux evolution
Local stagnation pressure
Heat-flux vs. Local stagnation pressure
MISSION REVIEW AND TPS SPECIFICATIONS
 Set of requirements defined with regards to the following criteria:
08-04-2013 / 15
MATERIALS STATE OF THE ART AND TRADE-OFF
08-04-2013 / 16
 State of the art considering:
 Analysis of previous “hybrid” concepts: SEPCORE® (ablator on top), SPA (CMC on top),
HybridTPS (Porous ceramic infiltrated).
 Review of ablative materials at worldwide level with emphasis on European supplier.
 Locate the project partners in this state-of-the-art
SEPCORE® (Herakles)
SPA (Astrium GmbH)
Trade-off
 Consider relevant ablative TPS materials at worldwide level.
 Elaborate a TPS material selection matrix -> Trade-off criteria
 Establish a materials ranking
 Locate project partner in the ranking
 Tailor this selection matrix to mission definition from WP1
MATERIALS SELECTION & PROCUREMENT
 Two types of phenolic ablator envisaged for the project:
 Cork based materials: NORCOAT FI (backshield)
 Graphite based materials: ASTERM (frontshield)
ASTERM
NORCOAT
(Astrium SAS)
(HPK Liéges)
08-04-2013 / 17
MATERIALS SELECTION & PROCUREMENT
Two manufacturers CMC (Cf/SiC) envisaged for the project:
 C/C-SiC (from DLR stuttgart).
 SICARBON© (EADS)
C/C-SiC
(DLR)
(EADS)
08-04-2013 / 18
BONDING & TPS ASSEMBLY
08-04-2013 / 19
 Selection of materials combination
Hybrid TPS selected
FRONT SHIELD
ASTERM
+
SICARBON
EADS
Ablative external shield
CMC core
BACK SHIELD
Joint at 100-150 ºC
NORCOAT
+
C/C-SiC
DLR + HPK
BONDING & TPS ASSEMBLY
08-04-2013 / 20
 Selection of adhesive:
 Inorganic based adhesive for the ablator/ceramic joint
 Organic adhesive for the ablator/ablator interface
 Criteria of selection:
o Performance at the different phases (launching, ascent, re-entry)
o Nature of the inorganic filler (alumina, silica, graphite, etc..)
o Wettability with the surfaces
o Curing temperature
o Ablator/ceramic interface temperature (aided by modeling)
o Thermal properties (CTE, Thermal conductivity)
Ablative external shield
Joint at 100-150 ºC
Charred Ablator
Joint at 1500 ºC?
CMC core
CMC core
First stage of the re-entry
Second stage of the re-entry
SIMULATION & TPS DESIGN
08-04-2013 / 21
 Simulation at different levels:
 Local thermo-chemical model
o At the micro/nano range
o Aided by 3D model technologies by the use of a nano-tomographic system (ICMCB)
 1D Thermal ablation model (Astrium SAS) -> Assessment of ablator thickness and interfacial
temperature -> Lecture by G. Pinaud.
 Thermal analysis (2D model) -> Materials properties as input
Local model on ablators
1D model (thickness vs. interface temperature
and recession)
 TPS Design
 Tile breadboard:
o Foreseen dimensions of 100 mm x 100 mm (planar)
o Including ablator/ablator joints and ablator/ceramic bonding.
 Further mass saving calculation wrt a whole capsule vehicle (i.e. CTV/ARV)
CHARACTERISATION & VERIFICATION PLAN
08-04-2013 / 22
 Characterization of materials and bonded structures:
 ASTERM ablator. Full characterization of thermal and mechanical properties
o Emissivity, coefficient of thermal expansion, specific heat, thermal diffusivity and
conductivity
o Tensile, compressive and flexural strength (including cryogenic temperatures)
 Adhesive:
o First screening based on bonding results and shear strength test
o Second screening based on thermal shock (QST-2 at INCAS) and cyclic test at
INDUTHERM (DLR Stuttgart)
o Final selection based on the performance and the plasma wind tunnel (correlation with
WP1 specifications).
 Final test of the breadboard at the PWT (IRS, Stuttgart). Comparison of perfirmace vs.
requirements.
Shear test at NCSR “Demokritos”
Thermal schock furnace at INCAS
CHARACTERISATION & VERIFICATION PLAN
 Cyclic test at INDUTHERM (DLR Stuttgart)
08-04-2013 / 23
CHARACTERISATION & VERIFICATION PLAN
 Final test of the breadboard at the PWT (IRS Stuttgart):
08-04-2013 / 24
CHARACTERISATION & VERIFICATION PLAN
08-04-2013 / 25
 Final test of the breadboard at the PWT (IRS Stuttgart):
o Facility PWK2 for CTV/ARV conditions
o Facility PWK1 for CSTS, using either RD5 or RD7 as plasma source for 5.7 MW/m2 condition
MAIN CONCLUSIONS AND FUTURE WORK
08-04-2013 / 26
 HYDRA is a new TPS concept that combines a low density ablator and a underneath hot
substructure.
 Main advantages are:
1) Mass reduction as compared with a solution based on a single ablator solution, while
2) Increase the temperature limits as compared with a re-usable system
 The project is running for one third of the total duration, the mission is selected, the requirements
complied and the characterisation/verification plan is ready.
 The materials trade-off is almost finished and the materials are have been just procured to the
partners. The simulation phase and bonding study has been initiated.
 Future effort will include the selection of the adhesive based on a complete screening study (2 nd
year) and the execution of the verification plan (3 rd Year) including characterisation under Plama Wind
Tunnel conditions.
 A mass saving analysis will be carried-out with regards to a full shield concept.
ACKNOWLEDGMENTS
 European Space Agency (M. Bottacini and B. Jeusset)
 European Commission
 Research Executive Agency (C. Ampatzis)
 EADS-Innovation Works (C. Wilhelmi).
 NCSRD (K. Triantou).
 IRS (T. Marynowski)
 ASTRIUM SAS (Y. Aspa)
08-04-2013 / 27
WEB PAGE
For more details visit the Project webpage: www.hydra-space.eu
08-04-2013 / 28
08-04-2013 / 29
END OF
PRESENTATION
Many thanks for
your attention