"[cont.] cargo compartment with controlled pressure and temperature conditions. The dimensions of the cargo compartment are determined by the payload class specified by the design [1].
The placement of the first stage propulsion system on the OS forms the configuration and dimensions of the rear fuselage compartment, and also determines the lateral placement of the OS relative to the launch vehicle and the principles of constructing mechanical and hydraulic connections.
The crew cabin is located in the forward part of the fuselage and is designed as a removable unit that does not participate in the power circuit. This solution allows for autonomous testing of the cabin and its systems and can simplify the organization of crew rescue in a number of emergency
situations.
To protect the structure from the effects of high temperatures during ascent and descent, it is envisaged to use removable heat-protective panels on surface areas where the heating temperature exceeds 1500°C.
The external OS configuration is shown in Fig. I.
3.2. Layout diagram of MTKS-I
In accordance with the composition of MTKS-I given in Section 2, it includes the RLA-135 orbital aircraft, an external fuel compartment and the first stage.
To ensure the maximum unification of the modular rocket blocks of the launch vehicle system being developed by NPO Energia, the design of the MTKS-I layout diagram (Fig. 2) is based on the rocket blocks of the first stage of the RLA-120, and the central modular block of the Ts MTKS is used on the RLA-150 launch vehicle also as a second stage."