CRASTE poster on TPS Development at NASA ARC

Fan, Wenhong

Stackpoole, Margaret Mairead

Thornton, Jeremy Joseph

NASA Technical Reports Server

New Materials Development Approaches!
•! NASA Ames is focused on qualifying and certifying TPS for current missions and 
on  developing new TPS for upcoming missions!
•! Three broad levels of development approach considered: !
•!  Advanced development: characterization & modeling of down-selected materials!
•!  Intermediate development: tailoring materials!
•!  Initial development: novel concepts/designing materials!
Heritage vs. New Materials!
•! Projects like to use heritage materials with proven performance:!
•!  Risk reduction strategy!
•!  Several low density (< 0.3 g/cm3) and high density (> 1 g/cm3) ablative TPS solutions have 
flight heritage!
•!  Technology gaps exist with current heritage materials!
•! As missions become more demanding, we will need higher capability materials 
— necessary to have a robust research and development program for both 
reusable and ablative materials!
New Rigid TPS Development!
Advanced PICA Approaches!
Mid Density CMCP!
ARC TPS Legacy!
Some Examples of ARC Developed TPS!
Tiles and Coatings!
SIRCA!
PICA!
" !Ongoing TPS Development at NASA Ames Research Center #
M. Stackpoole, J. Thornton and W. Fan #
ERC Inc., NASA Ames Research Center, Moffett Field CA, #
Summary!
•! TPS materials have special requirements for successful development and require a  
thorough understanding of:!
•! Chemistry / Materials Science!
•! Modeling!
•! Design!
•! Testing!
•!  Operating environment determines type and choice of materials!
•!  New materials being developed:!
•! Enabling for better, more efficient vehicle design and performance!
•! Improving safety!
•! Withstanding high heat fluxes/environments (outer planets)!
•!  NASA-Ames is working to make significant contributions in TPS material  
development for future space missions!
Shuttle Flight Testing of LI-900/
RCG vs AETB-8/TUFI in Base 
Heatshield Undamaged After 
Three Flights!
New Conformal/Flexible TPS Development!
Flexible PICA and SIRCA!
Flexible versions of PICA and SIRCA are currently under development at ARC!
Graded Ablators Development!
Acknowledgement!
Work is funded by the Hypersonics element of the Fundamental Aeronautics Program at 
NASA’s ARMD and the Entry, Descent, and Landing Technology Development Project!
The authors would also like to acknowledge Matt Gasch, Jim Arnold, Robin Beck, Tane 
Boghozian, Jose Chavez-Garcia and Mike Olson!
•! Every U.S. spacecraft that has entered the atmosphere has had some 
development or testing performed at NASA-Ames!
•! NASA-Ames is capable of handling all stages of TPS development from 
conception, material properties investigations, and modeling, to fabrication, 
testing and small scale end product delivery or technology transfer!
•! Ames is continually improving existing materials and developing new 
materials.   This work will enable safer, faster missions for access to space and 
to explore the solar system!
•! Effort started in 1970’s by ARC to provide NASA with TPS 
materials and processing expertise!
•! Successfully developed TPS materials including LI-2200, 
RCG, FRCI, Gap Fillers between RSI tiles, AFRSI, AETB, 
and TUFI that are used on all of the Orbiters!
•! Other surface treatment approaches and tile derived TPS 
concepts including HETC, TUFI-HT, ROCCI and TUFROC 
have been developed for higher temperature applications on 
future Reusable Launch Vehicles (RLVs)!
•! SIRCA is an insulative, ablative TPS material that is 
machinable to custom shapes and applied directly to the 
spacecraft.!
•! SIRCA was developed in the1990s at NASA Ames, and 
was a TPS choice for Mars Pathfinder, X-34 and Mars ’03 !
•! Both Mars Exploration Rovers used SIRCA. For this 
mission NASA ARC: !
•! performed afterbody aerothermal environment predictions. !
•! manufactured 35 SIRCA billets for the Backshell Interface 
Plate & Transverse Impulse Rocket System (TIRS) Cover TPS !
•! performed arc jet testing & SIRCA thermal response analyses!
Arc Jet test of SIRCA TIPS Cover 
at NASA ARC!
•! PICA was developed at NASA ARC in the 1980s. PICA’s 
low density (~ 0.27g/cm3), coupled with efficient ablative 
capability at high heat fluxes, made it an enabling technology 
for the Stardust mission. !
•!  At the time of the Stardust mission, PICA was a 
developmental material, with no previous flight heritage. 
NASA ARC transferred the PICA process to Fiber Materials, 
Inc. (FMI) & the PICA heatshield was manufactured at FMI!
•! A tiled PICA heatshield is used on MSL and is a backup TPS 
option for CEV !
Image of the sample return capsule 
post flight with PICA as the 
forebody TPS.!
•! Developed a family of ablator materials in the low- to mid 
density range with improved performance over PICA!
•! Tailor composition (for example, phenolic loading, 
Fiberform™/phenolic ratio)!
•!  Include additives to enhance certain properties in PICA 
variants for specific mission scenarios:!
•! Increased char strength!
•! Reduced recession!
•! Improved oxidation resistance!
Series of arc jet PICA variant models prior 
to testing!
Pre test arc jet image of a 0.86 g/cc 
CMCP sample!
Post test arc jet image of a 0.86 g/cc 
CMCP sample. !
Applications for flexible TPS include:!
•!  TPS deployed to form a large, blunt shape providing 
aerodynamic drag during hypervelocity atmospheric  
flight, while surviving heating from the bow shock 
wave that envelops the body. These hypersonic 
inflatable aerodynamic decelerators (HIADs) are one 
approach for the delivery of a large payload to the 
surface of Mars!
•! TPS used for large aeroshells where deployment is by a  
mechanical means rather than inflation!
•! TPS bonded directly to the substructure to replace rigid   
TPS and overcome challenges with rigid TPS that 
include gap fillers, tile size, and stringent requirement 
on carrier structure stiffness to minimize deflection in 
rigid systems!
•! Candidate systems have been processed and are 
currently going through a series of screening tests that 
include thermal, mechanical and relevant environment 
screening (arc jet, LHMEL)!
Flexible SIRCA! Flexible PICA!
Pre and post test flexible PICA tested in 
the JSC arc jet facility at 526 W/cm2, 0.35 
atm and a 20 sec exposure!
Pre and post test flexible SIRCA tested 
LHMEL at 114.6W/cm2 with a 20 sec 
exposure!
•! For missions with high heat flux, a lower overall mass can be 
obtained if the TPS composition changes from a carbon-based 
ablator at the heated surface to an insulator near the inner surface!
•! A graded material approach eliminates the need for  joints and/or 
bonding agents between material plies!
•! Monolithic graded ablator tiles and graded ablator in honeycomb 
(H/C) are being evaluated!
•! ARC experimental effort to date has focused on better optimizing 
processing!
•! A modeling effort is also in process as current response models 
are inadequate for graded (and multi-layer) ablators!
•! Preliminary results from arc jet testing of these materials is 
encouraging!
Monolithic graded ablator!
Graded ablator in H/C!
Pre and post arc jet tested graded ablator (graded from a carbon phenolic OML to a silica 
phenolic IML). Tested at 440 W/cm2, 27.7kPa atm and a 30 sec exposure!
•! Fully dense Carbon Phenolics are good TPS options in 
extreme conditions – !
•! Used at very high heat fluxes and high pressure conditions!
•! least favorable in terms of density!
•! Processing of fully dense carbon phenolics (including Chop 
Molded Carbon Phenolics (CMCP)) was optimized in the 
1960s. !
•! For intermediate conditions (peak heat flux of 1,000 to 
10,000 W/cm2 and stagnation pressures of 1.0 to 8.0 atm) it 
is necessary to reduce the density of fully dense CMCP 
materials to make them more efficient!
•! Our recent efforts have focused on lowering the density of  
CMCP ablators while still maintaining good mechanical and 
thermal performance. !
•! Systems developed had densities ranging from 0.8 to 0.9 g/cm3. 
This yields a ~40% reduction in density compared to fully dense 
systems. Reductions in density were achieved by incorporation of 
additives compatible with the base carbon phenolic system!
https://ntrs.nasa.gov/search.jsp?R=20110013352 2019-08-30T16:06:02+00:00Z


Ongoing TPS Development at NASA Ames Research Center

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