Magnesium has shown promise as a lighter-weight alternative to the aluminum alloys now used to make the main structural components of axially grooved heat pipes that contain ammonia as the working fluid. Magnesium heat-pipe structures can be fabricated by conventional processes that include extrusion, machining, welding, and bending. The thermal performances of magnesium heat pipes are the same as those of equal-sized aluminum heat pipes. However, by virtue of the lower mass density of magnesium, the magnesium heat pipes weigh 35 percent less. Conceived for use aboard spacecraft, magnesium heat pipes could also be attractive as heat-transfer devices in terrestrial applications in which minimization of weight is sought: examples include radio-communication equipment and laptop computers.

This work was done by John H. Rosenfeld, Sergei N. Zarembo, and G. Yale Eastman of Thermacore, Inc. for Johnson Space Center. For more information, download the Technical Support Package (free white paper) at under the Mechanics/ Machinery category.

In accordance with Public Law 96-517, the contractor has elected to retain title to this invention. Inquiries concerning rights for its commercial use should be addressed to:

Thermacore International, Inc. 780 Eden Rd. Lancaster, PA 17601 Phone No.: (717) 569-6551 E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Refer to MSC-23397-1, volume and number of this NASA Tech Briefs issue, and the page number.