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OK-M Reusable Orbital Ship

RSC Energia proposed its own space shuttle program in the 1980s. Between 1984 and 1993 the design office developed the OK-M ferry program ('Reusable Orbital Ship'). Three versions of the OK-M, OK-M, OK-M1 and OK-M2 were designed. Unlike MAKS, which was a TSTO system to be launched from an airplane, OK-M would use a conventional rocket. The basic variant OK-M would be launched by a Zenit rocket. It had a mass of 15 tons (3.5 tons of payload) and could carry two cosmonauts in the cabin, plus another four in an optional pressurized compartment located in the cargo hold. To save space in the cellar of 20 cubic meters, the coupling system would be located in the nose of the apparatus.

	OK-M	OK-M1	OK-M2
initial mass m is	15	31.8	30
Mass of payload t.
output to orbit H = 250km	3.5	7.2	10
H = 450 km.	2	5	6
returned to Earth t.	3,5	4,2	8
Landing weight t.
without return freight	10.2	22.4	17.6
with a return load	13.7	26.6	25.6
Mass of fuel and working bodies t.	1,8	2,5	2,7
Number of crew members
in the cockpit	2	4	4
in a special module	4	4	4
Number of maneuvering engines	2	2	3
Thrust of one engine kg.	400	2000	2700
Volume of cargo compartment m3.	20	40	40
Dimensions of payload m.
length	7	6.5	6.17
diameter	2.2	3	2.85

As a possible means of launch, the Zenith rocket (OK-M) was considered, along with "Energia-M" (OK-M2) and a reusable winged acceleration stage of the vertical start on the basis of the ship "Buran" (OK-M1). The starting masses of the systems were 400, 1060 and 850 tons, respectively. In parallel, the possibility of creating AKS using the transport plane "Ruslan" or "Mriya" as the first step. Another development of RSC Energia was a one-stage reusable airspace system of airfield basing, which included one-stage reusable aerospace aircraft (VCS) and ground- technical means of servicing and flight control. Work on VCS was started under the Decree of the Government of January 27, 1986. Terms of reference The Ministry of Defense was issued on September 1, 1986. VCS was a hyper-sonic rocket with combined multi-mode propulsion system on based turbojet air jet engine (WFD) and linear LPRE.

The initial mass did not exceed 700 tons (the mass of the structure was 140 tons). The payload is not less than 25 tons when moving to a reference orbit with a height of 200 km. Dimensions of VKS: length 71m. wing span 42m. height (along the upper edge of the fuselage) 10 m. The VCS was intended for operative cost-effective deducing of useful low loads in low orbits, maintenance of orbital groupings, transcontinental transportation, as well as for solving defense tasks in space. moosa and from outer space.

As a result of elaboration of various variants of aerospace systems, it was decided that the largest mass-energy efficiency was possessed by two-stage systems with vertical launch and horizontal landing of all stages with return to the airfield of the launch complex. Why is the vertically launching missile system, and not horizontally take-off, from the WFD? Liquid rockets [LRE] are reliable, tested and versatile and its characteristics do not depend of the flight speed. Existing serial jet turbine engines [WFD] work up to M = 3.5 (experimental types up to M = 6), but the creation of hypersonic WFDs operating up to M = 6-20 remaine a difficult problem.

Why a two-stage, not a single-stage system? Starting mass of one- stage design, with today's level of technology, will be more than two times more than two-stage mass. Starting weight of single-stage carrier can only be reduced if new structural materials are used, new technologies, new engines. But even when this level is reached the development of technology, nevertheless invariably energetically profitable is the multi-stage Although the single-stage system is more ambitious. Than it is obvious and explains not the weakening interest in it among developers. As a result of all this work, a new project was completed in RSC Energia, the reusable system GK-175 ("Energia-2"). It is a two-stage rocket consisting of four blocks "A" as a first stage and a wing- the second stage (block "C").

The "A" block uses engines with a thrust of up to 850 tons in vacuum, working on liquid oxygen and hydrocarbon fuels, on the second stage - thrust engines 230t in a vacuum, working on liquid oxygen and liquid hydrogen. Engines borrowed from from the LV "Energia" with a small upgrade in terms of providing multiple- of their use and forcing, which made it possible to take out into a reference orbit a 40t payload. At the first stage, it was intended to use the available the weight of the payload being put into orbit was would be 29 tons. It was planned to apply the control system completely from the Buran with a new mathematical software. Wing consoles, vertical plumage and aerodynamic controls (except for the flap) of the block "C" of the system are borrowed from the Buran.

The key difference was the change in the length of the "C" block in flight, aerodynamic requirements for the dimensions of the stage in the descent section. From this purpose, after putting into orbit and unloading the payload, the fairing load is pushed onto the oxidizer tank, as a result of which the length of the step is reduced with 60m. up to 44. Such a decision also made it possible to dispense with dumping head- fairing in flight, and the specific gravity of the thermal protection was even slightly lower than at the Buran. The results of design developments showed that the payload weight, output to orbit (with the starting mass of the system 2300 tons) approximately 1.5 times more than the payload mass output by the Buran or the Shuttle. Besides GK-175 really completely reusable system in orbit nothing remains, except for the spacecraft and all components of the system return to the launch site. The Buran has a second stage with engines and a unique control system entirely One-time, and the "Space Shuttle" fuel tank is disposable.

In the reusable space system "Energia-Buran" the first stage rescue scheme was more complex and expensive than "Space Shuttle", which was associated with the need to land on land, rather than in the ocean. When the development of the version of "Energy-M" the idea arose for the development of the winged block "A", a free-flying monoplane with an upper wing arrangement. The size of the wing center wing in the zone of the turning nodes does not exceed 6 m. (from condition placement of the block in the "package" as part of the carrier). V-shaped plumage folds in the starting position along the longitudinal axis of the block and fixed with locks on the center. The main landing gear legs are folded into fairings mounted on the block. The WFD can be installed on the pylon, near the center of mass of the block, or nose part of the block. Inside the nose fairing there is a fuel tank with kerosene made in the form of a torus.

The return path consists of three main parts:

1. a section of flight at high altitudes (more than 50 km.) in the presence of small aerodynamic forces - this area can be called a ballistic phase;
2. the turn of the block in the direction of the landing, at which the a sharp decrease in speed and altitude;
3. the planning section towards the landing site at a speed with a number M less than one.

The duration of the first section was 170 seconds. During this time, the unit from the launch to 270 km. reaches a height of 54 km. and a speed of 1.6 km / s. In the second phase of the trajectory, the deletion reaches 310 km. It must be compensated at the third section of subsonic flight with high aerodynamic quality.

The launching scheme provides for the launch of all engines from the Earth, flight for limits of the atmosphere, separation and descent of the exhausted blocks of the 1st stage, then the removal of the 2nd stage by the sustainer ["marching"] engines to an elliptical orbit with a height of 110- 200km. passive flight for 40 minutes, and extrapolation to a circular orbit. On orbit there is an unloading of the space from the second stage and carrying out the landing through one turn of stay on the orbit.

In case of an emergency flight, an additional delay of two a turn with the subsequent landing of a step on spare airdromes. Departure from orbit The brake pulse is generated by the auxiliary propulsion system.

In the future it was planned to replace four side blocks of the 1st stage with one which is actually a mirror image of the second stage. The steps would be to deprive only four engines RD-170 and lack of heat protection at the 1st stage. A package of two equal in size steps was a simple composition blocks articulated along the planes of the wings. One step is a bunch of oxygen- kerosene engines, the second - a bunch of oxygen-hydrogen. The planwas to instal three-component engines operating in the 1st steps on oxygen and kerosene, and in the second-stage regime, oxygen and hydrogen. Such an engine - RD-701 - was already being developed at that time.

Project GK-175 or "Energia-2" did not have a special pilot-of the ship. According to preliminary studies for manned flights the use of a cab-module was supposed. Separated and saved cabin with crew, with all the means of providing these functions it is possible to make a return it from any point of the flight trajectory "Energy-2". The draft used the cab-module as a cockpit that carried out the winged flight block "C" from the manufacturer to the space center or back, when equipping with WFD.

To operate as a part of the LV family of the Angara series of the GKNPTS, Khrunichev and NGOs "Lightning" on the basis of the universal rocket module of the 1st stage of the LV "Angara" (URM-1) to create a reusable accelerator "Baikal" similar to the block of the 1st stage GK-175. URM-1 is equipped with a wing, feathers, chassis, remote control for return flight, rocket engines orientation. The initial mass of such an accelerator is 130.4 tons. weight when landing up to 18 tons. length 28.5 m. the wing span is 17.1 m. height 8.5m. mean free path when landing 1200m. traction TRD 5t. The permitted number of flight uses is 10 (with bringing to 25).