RU2587740C2 - Spacecraft thermal blanket - Google Patents

Abstract

FIELD: astronautics.

SUBSTANCE: invention relates to heat insulation of spacecraft. Spacecraft thermal blanket consists of alternating layers formed non-flat polymer film with single or double-sided sputtering of metal, for example aluminium, and polymer network on which can be applied hot-melt adhesive. Polymers used as for making films and for making net include polyester, polyimide, aramid, arimid.

EFFECT: low heat conductivity and total weight of heat insulation.

1 cl, 6 dwg, 2 tbl

Description

The invention relates to the field of space technology, and in particular to the field of means of thermal protection of spacecraft.

Various thermal insulation coatings are used for thermal protection of spacecraft.

Known screen-vacuum thermal insulation of a spacecraft (USSR author's certificate 1839976), containing the outer layer of fiberglass or arimide fabric, an additional intermediate package of five screens made of metallized (the first three layers on the inside, and the fourth and fifth double-sided) polyimide film, intermediate layers of metallized on the inner side of the polyethylene terephthalate film, separated from each other by low-heat separators from the glass veil and the inner facing layer arimidnoy tissue. The disadvantages of this thermal insulation are the greenhouse effect of the outer layer, light contamination, significant dust emission and increased weight due to the use of inorganic intermediate layers.

Known screen-vacuum thermal insulation of a spacecraft (USSR author's certificate 1840181), consisting of an outer layer of fiberglass, intermediate layers of a flat or corrugated metallized polyethylene terephthalate film, turned with a metallized surface inward, separated from each other by low-conductivity separators made of glass fiber and an inner percolate or percalate polyethylene layer . The disadvantages of this thermal insulation are the greenhouse effect, significant dust emission and increased weight due to fiberglass and glass veil.

Thermal insulation is known (RF patent 2087392), consisting of an electrically conductive layer, a thermoregulatory layer, a polyimide film substrate, an intermediate layer of a polyimide network, which can be impregnated with epoxy resin and vulcanized, attached to the substrate, and a heat-reflecting coating of a polymer film material based on silicon compounds or polyvinyl fluoride. The disadvantages of this thermal insulation are light damage to the surface layer during installation, insufficient thermal reflectivity and low flexibility.

Known screen-vacuum thermal insulation of a spacecraft (RF patent 2344972), including a package of screens placed between the outer and inner facing layers, in which the outer facing layer is made of woven material with woven metallized threads. The disadvantages of this thermal insulation are the greenhouse effect and increased weight.

A screen-vacuum thermal insulation of a spacecraft with an external combined coating is known (RF patent 2397926), however, this coating is combined with flat films and the gluing or welding surface covers the entire film area, and the inner screens of metal-sprayed polymer films are laid with glass veil, which leads to the need protection of personnel from fiberglass dust in the manufacture of thermal insulation and high dust emission during operation of the spacecraft, leading to contamination of optics and other devices aratury spacecraft.

Thermal insulation is known (international application WO 2007/061304), consisting of metal and polymer layers, a sublayer of two metal layers and a fiber reinforced polymer. The disadvantages of this material are very large weight and too much thermal conductivity due to the tight contact of the metal layers with the polymer layers.

Thermal insulation is known (US patent 7252890), consisting of layers of a polymer metallized with aluminum or silver, such as polyester or polyimide, between which are layers of fiberglass or nylon, coated on the upper side with an IR-emitting inorganic material, then a photocatalytic layer of metal oxide and on the outside an electrically conductive layer of indium oxide or tin oxide. The disadvantages of this thermal insulation are the complex structure, insufficient tensile strength when stitching heat-protective mats, easy damage and contamination of the outer layer during the manufacture and transportation of spacecraft, and increased weight due to the use of inorganic substances.

Closest to the technical nature of the present invention is “Thermal screen-vacuum insulation” according to OST 92-1380-83, consisting of the outer layer of TSON-SOT fiberglass TU 156-66 or arimide fabric article 56420, intermediate layers of corrugated one-sided or two-sided metallized polyethylene terephthalate film, separated from each other by low heat conductive glass separators ХСВН-7 ТУ 6-48-05786904-147 and percals inner facing layer GOST 12125-66 or polyethylene terephthalate STU 3 113-105-64. The disadvantages of this thermal insulation are the greenhouse effect, significant dust emission and increased weight due to fiberglass and glass veil, as well as the need to protect personnel from dust from glass fibers in the manufacture of thermal insulation.

The aim of the present invention is to eliminate these drawbacks and reduce heat flow through the insulating material, as well as improving working conditions when assembling the material by replacing fiberglass with a non-dusting polymer mesh.

The technical result is achieved by the fact that the molded non-planar polymer (polyester, polyamide, polyimide, aramid, arimide) film with a one-sided or two-sided sprayed metal is glued or welded with a polymer (polyester, polyamide, polyimide, aramid, arimide) mesh only providing the surface of the bulges, which reduces the contact surface of the layers and thereby reduces the heat flux through the entire multilayer heat-insulating material composed of such films with glued or welded nets. On the polymer film, bulges can be formed in the form of various geometric shapes. These bulges can be the same or different and can be located at the same or unequal distance from each other. So, a polyethylene terephthalate film bilaterally sprayed with aluminum, formed from alternating rhombuses located perpendicular to each other (Figure 1), glued together with a polyester mesh (Figure 2) with a hot-melt adhesive, is folded into a multilayer material (Figure 3) - the material is in cross section. The film can be of different thicknesses, and one thermal insulation can be assembled from films of different thicknesses. Thermal insulation can be formed by a relief of squares (Figure 4), rectangles (Figure 5), circles (Figure 6), as well as various geometric shapes of a different shape. The polymer network can be made of fibers of different thicknesses and the distance between the fibers can vary.

Example 1

A polyester film with double-sided aluminum spraying, formed by a relief in the form of alternating perpendicular rhombic bulges, and a polyester mesh with a hot-melt adhesive are glued and folded into thermal insulation with alternating layers of film and mesh (30 films, 29 networks).

Example 2

A polyester film with one-sided aluminum spraying, formed by a relief in the form of regularly located rhombic bulges, and a polyester mesh are welded and folded into thermal insulation with alternating layers of film and mesh (20 films, 19 grids).

Example 3

A polyamide film with double-sided aluminum spraying, formed by a relief in the form of regularly arranged square bulges, and an aramid mesh with a deposited hot-melt adhesive, are glued and folded into thermal insulation with alternating layers of film and mesh (25 films, 24 mesh).

Example 4

A polyimide film with double-sided aluminum spraying, formed by a relief in the form of regularly arranged square bulges, and a polyimide mesh with a hot-melt adhesive are glued and folded into thermal insulation with alternating layers of film and mesh (30 films, 29 grids).

Example 5

Aramid film with one-sided aluminum spraying, formed by a relief in the form of regularly arranged round bulges, and a polyamide mesh are welded and stacked into thermal insulation with alternating layers of film and mesh (25 films, 24 mesh).

Example 6

A polyimide film with double-sided aluminum spraying, formed by a relief in the form of regularly arranged round bulges, and a polyester mesh with a hot-melt adhesive, are glued together and folded into thermal insulation with alternating layers of film and mesh (20 films, 19 networks).

Comparative example 1 (prototype)

Corrugated polyethylene terephthalate film metallized with aluminum and fiberglass are assembled for thermal insulation with alternating layers of film and fiberglass (30 films, 29 layers of fiberglass).

The test results of the thermal insulation collected in example 1 and comparative example 1 are shown in table 1.

Table 1 Example No. Specific gravity, g / m ² Electric heater power, W Specific thermal resistance, m ² × K / W Thermal resistance, K / W Relative efficiency,% average average one 185 0.86 4.97 4.70 410.8 388.4 110.85 1.05 4.65 384.1 1.14 4.48 370.2 Wed 1 (prototype) 188 0.86 4.47 4.24 369.1 350,4 one hundred 1.05 4.18 345.7 1.14 4.07 336.6

From table 1 it is seen that the thermal resistance of the material proposed in this invention is more than 10% higher with a lower weight EVTI compared with EVTI currently used.

Table 2 shows the data on dust emission according to example 1 and comparative example 1 (prototype).

table 2 No. Material Dust extraction of materials (number and size of particles) 0.5 μm 0.6 μm 0.8 μm 1.0 μm 1.5 μm 2.0 μm 5.0 μm 10.0 μm one Wed 1 (prototype) 5500 4800 3900 2750 2400 1900 250 22 2 According to example 1 500 400 300 150 fifty 10 2 0

From table 2 it can be seen that the dust emission of the material proposed in this invention is less than 10-100 times that of the currently used EVTI.

Claims (1)

Screen-vacuum thermal insulation of a spacecraft, including a convex-molded polymer, for example, polyester, polyimide, aramid, arimide, film with single or double-sided sputtering of a metal, such as aluminum, characterized in that the molded film is glued or welded with a polymer, for example, polyester, polyimide, aram nylon mesh, providing a fixed connection only on the surface of the bulges, while the hot melt can be applied to the mesh.

Images