controlled flight dynamics analysis

The calculation package includes:

1. Evaluation of required characteristics of control devices (aerodynamic control surfaces and jet vanes, liquid-propellant thrusters, etc.):

* Mathematical simulation of launch-vehicle flight;

* Development of launch-vehicle flight control algorithms;

* Evaluation of requirements for flight control devices and their drives.

2. Assessment of stability of stabilization systems:

* Assessment of stability by frequency methods;

* Assessment of technical stability by mathematically simulating the disturbed motion of the launch-vehicle, with the control devices dynamics taken into account;

* Development of corrective algorithms;

* Evaluation of stability margins.

3. Evaluation of functioning conditions of a launch-vehicle and its components:

* Envelopes of transverse g-loads, angles of attack and slip and deflection of control devices;

* Frequencies and amplitudes of oscillation of free surfaces of the liquid content in propellant cavities of a launch–vehicle as a solid body;

* Evaluation of disturbed motion parameters at the times when commands are generated to separate the SC, stages, etc.

4. Evaluation of launch-vehicle disturbed motion parameters from high-altitude wind probing data during prelaunch processing:

* Development of the special software for the launch meteorological-support workstation;

* Mathematical simulation of a launch-vehicle flight during a wind obtained by a weather balloon launched during the prelaunch processing, and assessment of allowability of the high-altitude wind for launching the launch-vehicle.

The employed calculation methods and software are applicable for disturbed motion analysis of light-weight, medium-weight and heavy-weight launch-vehicles with liquid and solid propulsion systems.

The following disturbing factors are considered in the mathematical simulation:

* wind and spreads of thermodynamic parameters of atmosphere;

* disturbances of launch-vehicle motion parameters caused by transient phases of the flight;

* spreads of the launch-vehicle’s weight, propulsion systems characteristics, mass and inertia characteristics and aerodynamic characteristics.

The proposed software and methodological ware have been successfully applied in the design of launch missions that have used launch-vehicles and space launch systems developed by Yuzhnoye SDO.

Analysis of dynamics of flight transient phases – launching, stage separation

The calculation package includes:

1. The software-and-methodological developments allow calculations and computer simulations of dynamics of any transients, in particular:

Launch of a launch-vehicle and jettison of the launching structural elements from the launch-vehicle:

* Launch of launch-vehicles from stationary above-ground and silo launchers;

* Launch of launch-vehicles from mobile above-ground launchers;

* Launch of a launch-vehicle from a carrier aircraft by schemes of bombing, landing operation, and from the carrier aircraft’s back.

Stage separation:

* Scheme of cold separation using solid-propellant retrorockets (SRMs)

* Scheme of hot separation with ignition of the engine of the starting stage prior to separation;

* Scheme of combined (“warm”) separation using a gas-jet retrorocket system.

Jettison of the payload fairing:

* by dividing the fairing into two half-fairings;

* by pulling the fairing off and away from the launch-vehicle using gunpowder engines.

Payload separation:

* Separation of large single spacecraft (SC) or a post-boost vehicle when launching a group of small SC;

* SC separation from the last stage.

2. Calculations to determine motion parameters of launch-vehicles and their elements in transient phases. Analysis of dynamics of these transients for specific design-layout schemes and working out of recommendations on control system command timeline and on design of units and components of launch-vehicles, the launch complex, separation systems.

3. Calculations for dynamic analysis of various mechanical systems (structures) of the customer and determination of the system’s elements motion laws, forces and moments acting on them in different operational conditions.

The software-and-methodological developments are applicable for both liquid- and solid-propellant launch-vehicles.

The transient analysis is carried out with account of practically all disturbing factors, in particular:

* Wind direction and speed;

* Atmosphere density spread;

* Error of determining aero- and gas-dynamic characteristics;

* Spread of mass and inertia characteristics;

* Errors of manufacture and assembly of the launch-vehicle and propulsion systems;

* Engine thrust spread;

* Skew and shift of engine thrust vectors;

* Elasticity characteristics of the rocket and its individual elements;

* Force action of the launcher’s elements on the rocket being launched.

For sea- and air-borne launch-vehicles there are also considered disturbed motion parameters of the carrier aircraft and pitching and rolling parameters of the marine platform.

The proposed software-and-methodological developments and services for transient dynamics analysis enable:

* to select an optimum diagram of the respective transient;

* if necessary, to work out specific recommendations on the design of units and components of launch-vehicles, the launch complex, separation systems.

* to determine required characteristics of the means ensuring reliability and safety of a particular transient;

* to select a sequence of issuing and executing the control system (CS)’s commands at each transient (CS command timeline);

* if necessary, to work out specific recommendations on the control algorithms at each transient;

* to calculate dynamic parameters of every transient for an upcoming launch of a particular rocket;

* to carry out a comparative analysis of launch results with design data.

Conducting the kinematic and dynamic analyses of mechanical systems during their design enables to make adequate design solutions in good time, optimize the design, reduce the scope of the systems’ development tests and refinement works during their commissioning. All this ultimately results in an enhancement of the application properties of the developed product.

The proposed software and methodological ware have been successfully applied in the design of launch missions that have used launch-vehicles and space launch systems developed by Yuzhnoye SDO.

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