本文主要討論微衛星TUUSAT-1A任務操作模式與飛行軟體規劃設計，首先介紹衛星任務目的與需求、各次系統需求與硬體元件規格，依任務需求規劃衛星的操作 區域與任務操作模式。任務模式共分為發射過程模式、進入軌道模式、穩定模式 、運行模式與安全模式，運行模式又依操作區域分為Receive、Download、 Capture、Beacon與Mailbox等次模式，各模式間的切換與執行邏輯皆以流程圖的 方式描述。飛行軟體依照次系統需求定義飛行軟體的基本功能，最後並規劃飛行 軟體的架構與未來發展方向。 This paper emphasizes on the operation mode and Flight Software design for a microsatellite TUUSAT-1A. The mission objectives and requirements of TUUSAT-1A are presented. The subsystems requirements and specifications are also described. The operation modes and areas are designed according to the mission requirements. The operation modes include the Launch, Orbit, Stable, Operation and Safe Modes. The Operation Mode consists of Receive, Download, Capture, Beacon and Mailbox Submodes. The alternation and executive logics between each mode are described by the flowcharts. The basic capabilities of onboard Flight Software are defined according to subsystem requirements. The architecture of Flight Software is also designed according to the operation modes design, as well as the future development.