Thermacore Offers First Heat Pipe Assembly for Operational Prototypes After Passing NASA Ames Hypersonic Tests

Lancaster, PA – Thermacore (, a leading provider of advanced thermal solutions, announced today that a Thermacore heat pipe assembly recently completed testing at the NASA Ames Arc Jet Complex, operating at very high temperatures in a hypersonic leading edge simulation, making it the first rigid embedded heat pipe module to operate successfully at those conditions. The demonstration confirms that the embedded heat-pipe design is a reusable alternative to traditional consumable ablative heat shield materials employed on hypersonic leading edge applications.

"The recently completed testing demonstrates that the Thermacore wing leading edge module has achieved technology readiness level six (TRL 6)," says John H. Rosenfeld, Senior Engineer for Lancaster, PA-based Thermacore. "This solution is now a real consideration for system and subsystem development for wings and engine inlets on hypersonic aircraft as well as thermal protection systems (TPS) for atmospheric entry, decent and landing of spacecraft."

Developed in conjunction with the Lockheed Martin Company, the tested Thermacore module used six embedded heat pipes. Under independent tests, two units were operated in an arc jet plasma field at environments representing hypersonic conditions. The results were the same for both units; thereby, demonstrating repeatability and reliability of the thermal protection system.

Unlike ablative materials that dissipate heat by erosion, the Thermacore assembly is a rigid structure that absorbs heat at the leading edge and then uses embedded heat pipes to spread the heat to larger surfaces, where it is radiated back to the atmosphere/environment.

The magnitude and capacity of the test at large sample sizes successfully simulated high-altitude atmospheric flight conditions -- a capability that makes the Ames Arc Jet Complex unique. In the arc jet chamber, the Thermacore heat pipe assembly was exposed to gases heated and expanded to very high temperatures and supersonic/hypersonic speeds by a continuous electrical arc between two sets of electrodes. The gases -- typically atmospheric air -- pass through a nozzle aimed at the test sample in a vacuum. The flowing gases produce a reasonable approximation of the surface temperature and pressure and the gas enthalpy found in high velocity, supersonic flow -- in this case, simulating high heat flux conditions at speeds from Mach 5 up to Mach 20.

Completing the Ames Arc Jet test regimen indicates the Thermacore module is ready for prototyping in an operational environment for spacecraft and hypersonic vehicles. The arc jet data has validated thermal models, heat shield design and performance characteristics.

A number of significant specific advances in the embedded heat pipe design were achieved:

• Modules were employed using multiple refractory metal heat pipes.

• Double containment of the working fluid was validated.

• Surfaces were fully coated for operation in air at temperatures significantly higher than previous maximum temperature capabilities.

• Full integration of 15-centimeter wide, 25-centimeter deep module was accomplished within the static edge of the wing mounting structure.

Heat pipes represent a preferred system for areas encountering very high heat flux, such as the nose cap, wing and engine inlet leading edges. The double containment system, necessary for multi-use unmanned or manned vehicles, was successfully demonstrated. 

Thermacore’s prior experience with hypersonic vehicle leading edge heat pipe development and refractory metal heat pipe envelope production extends to the National Aerospace Plane Program (NASP) in the 1980s to the current program.

At least ten prior development programs for hypersonic application of heat pipe assembly modules have been successfully completed by Thermacore. Development work encompasses various alkali metal heat pipes, embedding technology (brazing) of processed (filled) alkali metal heat pipes, joining and integration into dissimilar material composite structures, mounting and structural integration technologies, and oxidation resistance for long term operation above 1000°C -- all achieved through Thermacore’s integrated design and manufacturing capabilities.

To learn more about Thermacore‘s custom thermal management solutions, visit

About Thermacore

Founded in 1970, Thermacore specializes in the custom design, development, and manufacturing of highly engineered thermal management systems and components for a variety of OEM applications across a diversified set of global markets that includes Military/Aerospace, Computer, Communication, Energy Conversion, Medical, Transportation, Test Equipment, and Automotive. With over 40 years of experience in the design, development, and manufacturing of advanced solid conduction assemblies, passive two-phase systems, and active pumped systems, Thermacore brings unparalleled engineering design expertise and thermal solution performance, quality, and reliability to these markets. Thermacore employs more than 180 employees at 5 facilities located in the United States (Lancaster, Pennsylvania; Langhorne, Pennsylvania, Jefferson Hills, Pennsylvania, and Ronkonkoma Long Island, New York) and the United Kingdom (Ashington, Northumberland). Thermacore facilities are certified to AS 9100 Rev C., ISO 9001:2008 and ISO 14001:2004 quality standards. For information about Thermacore, visit

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Gregg J. Baldassarre

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