LIGHTWEIGHT REFLECTING STRUCTURES UTILIZING ELECTROSTATIC INFLATION

• Main Authors: JOHN H. COVER JR, WOLFGANG KNAUER, HANS A. MAURER
• Format: Patent
• Language: English
• Published: 08.12.1970
• Subjects: ANTENNAS, i.e. RADIO AERIALS; BASIC ELECTRIC ELEMENTS; ELECTRICITY

1,162,660. Aerials. HUGHES AIRCRAFT CO. 16 Oct., 1967 [31 Oct., 1966], No. 47045/67. Heading H4A. A radio wave reflector comprises two electrically conductive and flexible meshes or mesh portions which are preformed to define predetermined surfaces, means for supporting the meshes or mesh portions about their respective peripheries, and means for charging the meshes or mesh portions so that a preformed shape of at least one of them is maintained by the consequent electrostatic forces. As described, a reflector support structure comprising a tubular ring 30, Fig. 3, is attached to a spacecraft body 31 by means of three tubular arms 32, and a reflecting mesh 10 and a contouring grid 11 are attached at their peripheries to the said ring. The spacecraft body also carries a radio feed means 15 directed towards the reflecting mesh 10, and a conductive member 34 ending in a spherical member 33. The members comprising the mesh 10 may be quartz fibres coated with aluminium, and they are spaced apart by less than a wavelength at the highest frequency used. The members comprising the mesh 11 are spaced sufficiently apart to be substantially transparent to radio waves of the frequencies used. The ring 30 and the arms 32 are collapsible, and are extended when the spacecraft has been launched in orbit. The meshes 10, 11 are then electrified with the same polarity by means provided, charges of opposite sign being collected on the member 34. Electrostatic forces of repulsion cause the meshes 10, 11 to assume pre-formed shapes, that of the mesh 10 being such as to reflect waves from the feed means 15. Ion (or electron) expelling means may be provided instead of the members 33, 34 for removing the charges of opposite sign to those which maintain the shapes of the meshes. In another embodiment (Fig. 4, not shown) the contouring grid and reflecting mesh are insulated from each other, and in use are charged with opposite polarities, and there is no unwanted charge for disposal. An embodiment is also described (Fig. 5, not shown) comprising a light weight reflecting mesh structure which is preformed into a closed cylinder. This may be deployed as a decoy or marker reflector in space. Other shaped closed meshes, such as spheres, are also suitable.