European Space Agency

High Performance Loop Heat Pipe


The main objective of the High Performance Loop Heat Pipe program can be split in three tasks :

  • To design, develop, manufacture and test a High performance Loop Heat Pipe for deployable radiator (in the frame of AlphaBus program) and large power range applications.

  • To deliver to Europe Space community a competitive (performance and price) and Itar free LHP product.

  • To combine European LHP background and competences for product consolidation and use (European Harmonisation).

click for larger image


The main contributor of the LHP performance being the heat transfer in front of a porous media, the main challenging activity will address the mastering of metallic porous media with some insulated ones. Thus, the critical path and the main issue will be the definition and design of evaporator inner design.


This thermal device is designed for large powerful SATCOM, which should use deployable radiator. It will then allow having highly dissipative payload onboard limited spacecraft volume.


The Loop Heat Pipe is a thermal device, which carry heat owing to latent heat of vaporisation, from the hot dissipative equipment to the cold external radiator. This device, totally passive (no mechanical pump), use a capillary evaporator which provides a two phase flow owing to capillary suction. This suction is performed in front of a porous media. The proposed architecture plan to improve the heat transfer coefficient in order to have large flow rates and an efficient thermal pump.


Through several extensive concurrent engineering sessions, it is proposed to list all key issues which could improve the Loop Heat pipe performance. These points have been presented at a concept review and evaluated during some trade-off activities. At the end of this phase, a design was selected and Engineering model of LHP manufactured and tested.

Current status

In phase 1, after consolidation of the Loop Heat Pipe specification, the concept definition has been achieved
Then in phase 2, the design trade off, the detailed design analysis and definition files were performed.
During the on-going phase 3:

  • The LHP² manufacturing file has been issued,
  • The Development Model has been manufactured.
  • The test plan has been issued & presented at the Test Readiness Review on the 07/09/2006.

Most of the LHP test has been successfully completed.

The thermal vacuum test has been delayed until April 2007.

Status date

Monday, November 19, 2007 - 15:15