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计划于1998年9月发射的广角红外探测器(WIRE)是NASA小型探测器(SMEX)系列的第5颗航天器。WIRE任务要以极高的星成形速率对星系进行4个月的勘察。WIRE是一种偏置动量、三轴稳定的星指示器,它提供高精度指向并且在每圈轨道上能自动捕获8～10颗目标星。其大部分部件是以以前的SMEX任务为基础设计的,由于任务寿命较短和冷冻剂受限制,因此WIRE提出了新的严禁太阳和地球进入视场的要求以保护仪器和储存的冷冻剂。本文描述了WIRE姿态控制系统飞行软件(ACS FSW)的设计,其中着重描述设计中新颖的或有较大改进的部分。这包括了错误检测与纠正(FDH)、模式管理模块和表驱动结构。ACS FSW处理航天器的所有命令与控制,并且自动进行FDH以确保仪器与航天器的安全。所有软件和确定运行哪些软件的控制模式管理器组成一个整体。级别低的模式“更安全”是因为使用的敏感器和执行机构更少;当进入级别更高的控制模式时,模式管理器将激活更多的软件功能,并且提供的姿态控制精度更高。FDH一旦检测到超出约束条件的情况就立即为了安全转换到级别低的控制模式。WIRE的ACS FSW满足目标捕获、检测约束条件和指向的所有要求,它通过加载参数表为地面提供重构系统参数的简易方法。
The Wide Angle Infrared Detector (WIRE), scheduled to launch in September 1998, is the fifth spacecraft in the NASA Small Detector (SMEX) series. The WIRE mission is to conduct a 4-month survey of galaxies at very high star formation rates. WIRE is a biased, three-axis, stable star indicator that provides high-precision pointing and automatically captures 8 to 10 target stars per orbit. Most of its components are based on previous SMEX missions, and due to shorter mission life and limited refrigerant, the WIRE has proposed new requirements forbidding the sun and Earth from entering the field of view to protect the instrument and stored cryogen. This article describes the design of the WIRE Attitude Control System Flight Software (ACS FSW), highlighting new or significant improvements in the design. This includes error detection and correction (FDH), pattern management module, and table-driven structure. The ACS FSW handles all command and control of the spacecraft and automatically performs FDH to ensure instrument and spacecraft safety. All software and the control mode manager that determines what software to run together form a whole. “Low-level mode” is “safer” because fewer sensors and actuators are used; when entering higher-level control modes, the mode manager activates more software functions and offers more precision in attitude control high. The FDH immediately transitions to a lower level control mode upon detection of an out-of-bound condition. WIRE’s ACS FSW meets all requirements for target capture, detection constraints, and pointing, and it provides an easy way for the ground to reconstruct system parameters by loading a parameter list.