1. Liquid LVs propellant consumption control terminal system
Yuzhnoye SDO Proprietary
Liquid LVs propellant consumption control terminal system 1

2. Propellant Consumption Control System (PCCS)
Principles of system arrangement
In the calculated-nominal conditions of LV flight the process of propellant consumption from the stage tanks is ensured by calculated-nominal values of propellant volume. However, in practice the flight of LV is accompanied with different random disturbances, effecting the process of propellant consumption. Such disturbances include errors in the main engine thrust and propellants ratio setting, LV tanks loading errors, aerodynamic parameters of LV etc. Taking into account the above factors, it is necessary to have a certain guaranteed propellant reserve in each of LV tank, in addition to the guaranteed useful propellant volume which is fully consumed under calculated-nominal conditions. The guaranteed propellant reserve is consumed during disturbance modes of flight for compensation of random disturbances, requiring additional power consumption. Allocation of the guaranteed propellant reserve out of total propellant mass, loaded into LV tanks, is possible only at the expense of relevant reduction of useful propellant volume, which results in decreasing of LV nominal lifting capacity.
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3. Yuzhnoye SDO Proprietary
Propellant Consumption Control System (PCCS)
Principles of system arrangement
Values of the guaranteed propellant reserves portion, used for compensation of random disturbances, may reach above 5% of the useful propellant volume mass. The volume of such non-depleted propellants may be significantly reduced to the acceptable level (~0.3% of the useful propellant volume) by means of using special systems at LVs, generally named as propellant consumption control systems (PCCS).
The main advantage of the proposed PCCS is its high power efficiency. Thus, for example, application of PCCS at Yuzhnoye developed three stage LVs allowed to increase payload capabilities of LVs in payload equivalent to above 1000 kgf in average (with injection into geostationary transfer orbit).
PCCS system is used on all liquid LVs developed by Yuzhnoye SDO.
Yuzhnoye SDO Proprietary

4. Propellant Consumption Control System (PCCS)
PCCS designation
Propellant consumption control system (PCCS) is designed for:
simultaneous consumption of oxidizer and fuel from LV tanks by the moment of the stages engines shutdown;
full propellant depletion from LV tanks by determining the minimum allowable residual propellant, volume required only to ensure fail-safe engines shutdown.
Yuzhnoye SDO Proprietary

5. Yuzhnoye SDO Proprietary
Propellant Consumption Control System (PCCS)
Composition of the system
PCCS hardware may be built as on autonomous system or as a part of LV control system hardware. PCCS system usually includes on-board equipment are and ground test and checkout equipment. PCCS structure (for one stage) is presented at the picture.
PCCS on-board equipment includes:
level sensors, installed in oxidizer and fuel tanks of each stage;
converting and computing unit of the system;
electromechanical drives;
actuation devices (throttles), located in fuel pipelines of propulsion systems;
on-board harness.
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6. Yuzhnoye SDO Proprietary
Propellant Consumption Control System (PCCS)
PCCS structural scheme (one stage is shown)
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7. Yuzhnoye SDO Proprietary
Propellant Consumption Control System (PCCS)
PCCS level sensors
PCCS level sensors are designed for measurement and issuing data on the propellants surface motion over the specific volumes in LV tanks.
Sensors are discrete level meters of with the system of sensitive elements (inductance coils), located along the vertical axis of the sensor at the distances corresponding to the predicted propellant in the tank.
Combined with freely floating at the liquid surface hollow magnetoconductive floats, the sensing elements ensure issuing data on the propellant level position.
General view of PCCS level is presented at the following slides.
Yuzhnoye SDO Proprietary

8. Yuzhnoye SDO Proprietary General view of PCCS level sensor
Propellant Consumption Control System (PCCS)
PCCS level sensors
1 – casing;
2 – rod;
3 – sensing element;
4 – sealed connector pipe;
5 – sealed connector outlet;
6 – electrical connector;
7 – coat-attenuator;
8 – float;
9 – support screw with coupling nut.
Yuzhnoye SDO Proprietary
General view of PCCS level sensor

9. Propellant Consumption Control System (PCCS)
PCCS level sensors
External view of level sensors (without coat attenuator)
Yuzhnoye SDO Proprietary

10. Propellant Consumption Control System (PCCS)
PCCS level sensors
External view of level sensor (a rod with sensing elements)
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11. Yuzhnoye SDO Proprietary
Propellant Consumption Control System (PCCS)
Composition of the system
converting and computing part of PCCS is designed for processing and receipt of measurement data, coming from level sensors and formation according to the algorithm of controlling effects on PCCS system activation device (fuel throttle).
Converting and computing part of the system is built on the basis of a proprietary designed controller or on-board digital computer of LV control system, where algorithm of PCCS operation is implemented.
For provision of harmonization of the system components, the converting and computing part also includes the following:
- amplifiers-converters, designed for feed voltage supplying to PCCS level sensors, conversion and formation of the sensors output signals into format compatible with CCP controller (control system of on-board digital computer);
- exchange device, designed for formation of electrical commands to electric drives by the controller commands (or on-board digital computer);
- telemetry interface unit, etc.
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12. Yuzhnoye SDO Proprietary
Propellant Consumption Control System (PCCS)
Composition of the system
Electrical drives are designed for converting electrical control commands, coming from PCCS converting computing unit output, into mechanical control effects on activation devices of the system.
Activation devices (throttles) are designed for the propellants mixture ratio variations within the allowable range of engine setting.
For PCCS on-board equipment adaptation to the conditions of a specific launch and testing the system operation during preparatory operations with PCCS during assembly activities at the manufacturing plant and at the launch site, the ground checking and testing equipment is used.
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13. Possible ways of cooperation
Holding of introductory presentations, lectures, issue of technical reports on the main principles of PCCS formation and operation.
Preliminary designing of PCCS according to Specifications (initial data) of the Customer.
Development of design documentation, procedures and methodologies, operational documentation, manufacturing of pilot models and carrying out development testing of PCCS on-board and test and checkout equipment. Delivery of standard (serial) sets of on-board- and checkout and test equipment to the Customer.
Adaptation of design documentation to the requirements (norms) of the Customer.
Providing support during the system commissioning and operation.
Yuzhnoye SDO Proprietary