Spacecraft Control System Development

Abstract

SMACS Spacecraft MAnagement and Control System is prepared as common fundamental system for ETS-VIII and ALOS which will be launched by H-2A Launch Vehicle. The spacecraft control system is to carry out operation planning, conditions observation, control and analysis of the spacecraft. And the spacecraft control system supports more reliable spacecraft operation and reduces operator’s load. This paper shows the functions of the SMACS and basic operation for a spacecraft by SMACS. 1.INTRODUCTION NASDA Tracking Control System has three systems. -Communication Tracking System (Ground Network system and Space Network system) tracking station, network control, network management,etc -Flight Dynamics system Orbit determination, orbital event prediction, maneuver planning, etc -Spacecraft Control System . Now we developed a Spacecraft Control System of NASDA which is named SMACS(Spacecraft Management and Control System).SMACS consists of five subsystems and as shown bellow; -SIMS(Spacecraft Information Management Subsystem) SIMS makes and checks information database and operating procedure for spacecraft control. -SOPS(Spacecraft Operation Planning Subsystem) SOPS plans spacecraft operation and gets the resource of Tracking Network of NASDA. -SPOC(Spacecraft Processing and Operation Control subsystem) SPOC processes telemetry and command data according to the information database made by SIMS. -STAD(Spacecraft Telemetry data Analyzing and Drawing subsystem) STAD archives, analyze and draw telemetry and command data. -SCOT(Spacecraft Control and Operation Terminal subsystem) SCOT monitors and controls four subsystems. 2.SYSTEM CONFIGURATION SMACS configuration is shown in Figure 1. The outlines of each sub-system are described as follows. Fig 1 SMACS configuration 2.1 SIMS SIMS makes the information database for other subsystem and standard operating procedure for spacecraft. SIMS checks the information database and the procedure, and notifies the new information database to each subsytems. The information database consists of the system information and the operating information. The system information has the external information (station ,network planning system, etc), satellite processing type(CCSDS or non-CCSDS, GEO or LEO, etc) and the operator information(user-ID, access information, etc) The operating information has telemetry, command processing information. The operating procedure consists of sending commands and confirmation of telemetry for spacecraft . 2.2 SOPS SOPS gets the orbit information (station visibility, eclipse, etc) from FDS and restriction information from Tracking Network of NASDA, gathers mission user requests, and makes the request information to Tracking Network of NASDA. Next SOPS makes the spacecraft operation plans with resource. The spacecraft operation plans consists of the resource information and the operating procedures. For example, SOPS plans eclipse, maneuver operation by orbital event information, and plans mission operation of mission users. The spacecraft plan is prepared by unique planning method for each spacecraft. (single mission or multi-mission spacecraft) For example, single mission spacecraft doesn’t adjust spacecraft plan among some mission users requests. SOPS decides the period of command operation for mission users. And SOPS prepares telemetry data value in future for prediction which is evaluated by SPOC. And common functional part provides making plan by SOPS operator. 2.3 SPOC SPOC processes telemetry and command data according to the information database made by SIMS. SPOC controls and monitors spacecraft according to the schedule planned by SOPS. And SPOC can process and control Tracking Network of NASDA SPOC distributes spacecraft telemetry data (raw telemetry data or converted telemetry data) to DB SOP SMACS