NASA Technical Reports Server (NTRS) 19740000161: Electrostatically controlled heat shutter

4r B74-10161 September 1974 NASA TECH BRIEF NASA Pasadena Office NASA Tech Briefs announce new technology derived from the U.S. s p ace program...

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B74-10161

September 1974

NASA TECH BRIEF NASA Pasadena Office

NASA Tech Briefs announce new technology derived from the U.S. s p ace program. They are issued to encourage commerciat application. Tech Briefs are available on a subscription basis from the National Technical Information Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546.

Electrostatically Controlled Heat Shutter

Heated Object

Cold Outer Spa.e

. Heat

Electrostatically Controlled Heat Shutter

The problem:

How it's done:

A number of components used in spacecraft generate heat and require some form of cooling. The only cooling methods available, however, are by conduction and radiation. Unfortunately conduction and radiation cooling are relatively inefficient: conduction is impaired by the thermal resistance of the materials used, and the low radiating temperatures generated by these components We inadequate for effective cooling by radiation.

The cooling device, as shown in the figure, consists of a chamber filled to a pressure of 1 atmosphere with N2, Ar, or other ionizable gas. The device encloses electrostatic probes which are electrically connected and face the opposite ends of the chamber. The chamber ends are made of a good thermal conductor such as copper; the walls are made of a poorer thermal conductor such as stainless steel. One chamber end, the hot plate, is in direct contact with the heat-generating component, and the other, the cold plate, is in direct contact with the cold environment. When high voltage is applied between the chamber case and the electrostatic probes, the neutral gas

The solution: An electrically controlled chamber filled with inert gas efficiently removes heat from the heat-generating components.

(continued overleaf) This document was prepared under the sponsorship of the National Aeronautics and Space Administration. Neither the United States Government nor any person acting on behalf of the United States

Government assumes any liability resulting from the use of the information contained in this document, or warrants that such use will be free from privately owned rights.

molecules ionize around the probe near the hot plate and form an ionic wind. All of the ions near the hot plate are electrostatically attracted to it, to become neutral and absorb heat energy from the plate. These hot neutral gas atoms are then moved to the vicinity of the cold plate by the ionic wind. There the atoms are ionized again and attracted to the cold plate where they release the heat energy they carry from the hot plate. The ionic wind then moves the cooled atoms back toward the hot plate. Since the ionic wind intensity is directly proportional to the voltage applied to the electrostatic probes, the rate of heat removal is controlled by varying this voltage. The system can be reversed to bring heat from an external source to a component.

Patent status: This invention has been patented by NASA (Us. Patent No. 3,763,928). Inquiries concerning nonexclusive or exclusive license for its commercial development should be addressed to: Patent Counsel NASA Pasadena Office 4800 Oak Grove Drive Pasadena, California 91103 Source: Uoyd J. Den of Caltech/JPL under contract to NASA Pasadena Office (NPO-1 1942)

Note: Requests , for further information may be directed to: Technology Utilization Officer NASA Pasadena Office 4800 Oak Grove Drive Pasadena, California 91103 Reference: B74-10161

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B74-10161

Category 03,06,02