From SPIRAL to MAKS

Main Principles of the MAKS Control Organization

Dr. Nekrasov O.N., Korovin K.G.
Distribution of the control functions between the Onboard and Ground Based Complexes for the direct operative reception by the consumers of the target information as basis of the MAKS control organization is considered.

The MAKS operational features are: multi-use application, air launch from a carrier-plane, high immediacy of missions solutions, capability to launch from points with practically any geographic coordinates, necessity to provide low maintenance charges and small cost of payload injection. These features require from project designers to develop new principals of aerospace system control organization. In this connection, during their development all up-to-day achievements of aerospace techniques, including those realized in BURAN project and the most prospect trends and conceptions of control systems produced at the edge of aviation and space industries are being integrated in one piece.

The most important aim of MAKS control organization is efficient distribution of control functions between on-board and ground-based facilities with simultaneous decision of traditional question concerned functions of the operators in on-board and ground-based control circuits. The process of control of aerospace system flight provides realization of following functions:

• flight planning and flying mission preparation;
• control of pre-start preparations, including carrier plane flight to a start-up region and MAKS second stage launch;
• flight control, including at target task solution and control of solutions of target tasks;
• flight navigation support, including determination of coordinates, motion and orientation parameters of flying vehicles, guidance;
• stabilization of given modes at orbital leg of flight, on-board system mode control, including reconfiguration at failures and faults;
• inter-flight service control, including integrated control and forecasting of flying vehicle technical sate.

In the course of aviation and space techniques development in addition to improvements of radio equipment and automation elements the control functions were enlarged and their re-distribution between on-board and ground-based facilities as well as between automatic and manual control circuits took place. At that, in accordance with law of technical development such re-distribution was frequently either one-sided or carried unjustified reserved, equal to full exchange, character. The first case worsens technical side of business and system efficiency on the whole, the second considerably increases creation cost and system maintenance charges with slight system efficiency increment. The example is a realization of BURAN project where perfect for those times on-board automatic control complex, wide-ranging as by quantity and assortment of technical means as by ground-based complex cost, was created. However, later the ground-based complex was appeared not to be able to support guidance at such important flight legs as injection, descending and landing. The main reasons are as follows:

• information enters ground-based circuit after processing by on-board computers;
• transmit-receive and information processing sections, including analysis of operators’ actions, have inadmissible time schedules and delays for active flight legs;
• information from ground circuit again enters computers of on-board circuit which doesn’t need such information at normal (regular or specified non-regular) situations and at abnormal situations such information doesn’t allow to settle it due to indicated time delays.

The serious problem, still not resolved, is low immediacy of getting information from orbit due to impossibility of direct connection of consumers of such information to the ground-based control circuit. For example, “immediacy” of getting information from the existing orbital satellite group differs from one week to one and a half month. Certainly, in many cases, it is explained by bureaucratic monopolization of access to information, however, technical principles of ground complex organization practically excludes its purposeful application.

The conclusions

The analysis of available experience and generalization of modern trends and conceptions adjusted in aviation and space industries allow to define following major principles of MAKS control organization:
1. The on-board control complex allows to realize maximum, full in ideal, autonomy of task decision for flight control. At that an orbital stage can be used in manned or unmanned modifications and operators’ presence aboard or in control circuit is determined only by circle of solved tasks.
2. The ground-based control complex conditionally divides into two main parts in accordance with circle of solved tasks. The first part, called at present development phase as CB ASS (command center of aerospace station), provides control task solution by operational planning, preparation and MAKS flight execution as well as by inter-flight service. The CB ASS is permanent, for each flight, functional structure providing only control of execution of flying mission tasks during flight and if necessary its exchange or correction. The second part is existing and prospect control systems, centers, means and complexes of different departments and industries participating in task fulfillment for particular flight and consuming corresponding information. The indicated facilities have a possibility for flexible operative individual or group inclusion into MAKS functioning at solution of corresponding tasks with parallel execution of own functions with consideration of information received from MAKS. Such principles of control distribution between on-board and ground-based facilities as well as within ground facilities provide maximum efficiency of MAKS application. These principles provide also immediacy and task orientation of information received during MAKS utilization as well as to reduce creation cost and, what is of the same importance, maintenance charges of aerospace system.