Model 1. It is intrinsic to the initial period of the superinsulation investigation. The superinsulation is considered as a system of parallel layers with surfaces reflecting thermal radiation according to the Stephen-Boltzman law. In addition, the thermal shunting of the layer is absent in the model. This model implied a small degree of surface blackness. The superinsulation according to Model 1 is considered as a system of poor or "defected” reflectors [13]. The following superinsulation damage sources have been proposed: adsorption of water vapours, working liquid and volatile components of the padding material [14] as well as tunnel-radiation phenomena in the area of contact between the padding material and the reflecting surface [15].

Model 2. It describes the superinsulation as a system of screen-reflectors with a small value of the emissivity factor and heat shunted by means of conductive-conduction pads located between them [16-18]. In accordance with this model, the pad’s parameters, the fibre diameter, the total thickness of pad, the number of bonds in the padding should be of major importance. In addition, the fibre diameter and the pad’s thickness is determined by the number of contact areas in the heat flow direction and the amount of the bundle, which is normally concentrated in the contact area, is determined by the heat resistance of this contacts.

Model 3. It describes the superinsulation as a system of effective screens of radiant energy shunted by pads, which entire heat resistance is concentrated in the area of their
contact with the screens. According to this model, the pad thickness is of secondary value [19-21].

Model 4. It describes the superinsulation as a system of screens with a small degree of surface blackness shunted by the interlayer gas being in the free molecular mode (the Knudsen criterion >1). According to this model, the pad thickness is insignificant, the main importance belongs to the number of sections, into which the gas space is divided and the residual gas pressure in this space. The pad parameters are important only insofar as they influence on the residual gas pressure [22-28].

Model 5 (belonging to the author of this review). It describes the superinsulation as a system of screens with a small degree of surface blackness shunted by the interlayer gas being in the free molecular mode. According to this model, the pad thickness is insignificant, the most important are the number of sections, into which the gas space is divided, the screen material, the composition and pressure of residual gases in this space as well as the effusion magnitude and composition. The pad parameters are important only in connection with the fact that they influence on the residual gas pressure [6,7].

Model 6 (G. G. Zhun’s model). It describes the superinsulation as a peculiar pump [29].

Model 7 (belonging to the author of this review). It describes the superinsulation as a “quasicapacitor”, in which the charge generator on the superinsulation screens is the evaporating cryoliquid [30].

Model 8 (belonging to the author of this review). It describes the superinsulation as a system being unstable in warm layers and having the number of adsorption centres, which varied depending upon the ambient conditions.