Abstract: In order to produce lightweight mirror structures or other reflecting components, preformed silicon elements of sufficient wall thickness are applied to a CFC or CMC substrate structure with the dimensions of the component to be produced, at a temperature in the range 1300.degree. C. and 1600.degree. C. either in vacuum or in a protective atmosphere. In this way a mirror structure or reflector is formed directly. It is possible to work at temperatures in the range of 300.degree. C. to 600.degree. C. when the silicon is applied in the form of a preform such as a wafer, which is joined to the substrate by way of a zone of a melt eutectic incorporating a nonferrous metal, which is preferably gold. The surfaces are subsequently coated.

Abstract: In order to produce lightweight mirror structures or other reflecting components, preformed silicon elements of sufficient wall thickness are applied to a CFC or CMC substrate structure with the dimensions of the component to be produced, at a temperature in the range 1300.degree. C. and 1600.degree. C. either in vacuum or in a protective atmosphere. In this way a mirror structure or reflector is formed directly. It is possible to work at temperatures in the range of 300.degree. C. to 600.degree. C. when the silicon is applied in the form of a preform such as a wafer, which is joined to the substrate by way of a zone of a melt eutectic incorporating a nonferrous metal, which is preferably gold. The surfaces are subsequently coated.

Abstract: For the production of lightweight reflectors or mirror structures, metallic silicon of sufficient thickness is applied to a CFC or CMC substrate preform structure having the dimensions of the component to be produced by a heat treatment process, in particular at temperatures between 1300.degree. C. and 1600.degree. C. and in a vacuum or in a protective atmosphere. In this way, reflectors or mirror structures are formed directly. It is possible to work at temperatures of 300.degree.-600.degree. C. when the silicon is applied in the form of wafers which are joined to the substrate preform by way a zone of a melt eutectic incorporating a nonferrous metal. Preferably the nonferrous metal is gold.

Abstract: For the manufacturing of an oxidation-stable component that can withstand temperature changes for space travel, a solid CFC-body with a density of from 0.1 to 0.8 g/cm.sup.3, which has nondirectional short fibers, is made from short carbon fibers and a hardenable resin binder. From the solid CFC-body, a CFC-blank having the dimensions of the component to be manufactured is prepared by means of turning or other material cutting. The CFC-blank is infiltrated with pyrolytic carbon to a density of no more than 1.0 g/cm.sup.3 and then with metallic silicon so that its density amounts to more than 2.0 g/cm.sup.3. A portion of the metallic silicon is reacted with the pyrolytic carbon to form silicon carbide. The proportion of the unreacted metallic silicon which remains in the component after this reaction amounts to at least 15 percent by weight.

Abstract: An insulating layer is effected between a propellant charge in the interior walls of a combustion chamber of a rocket engine by applying an expandable plastic to the inside of the combustion chamber housing between the housing and the outer circumferential wall of the propellant charge then expanding the plastic. Advantageously the combustion chamber is preheated before introducing the charge and the expandable plastic into the combustion chamber. Preferably the ratio of the layer of the thickness of the expandable plastic to the spacing between the propellant charge and the walls of the combustion chamber ranges from 1 to 11/2; 1 to 1 and 1 to 3. The expandable plastic is advantageously a polybutadiene.