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This document outlines the pre-launch execution sequence for satellite deployment. It includes critical steps such as spinning up reaction wheels, initializing guidance, navigation, and control (GNC) algorithms, and diagnostics for stabilization and power deployment. Following the release, antennas will be deployed, and attitude data will be recorded. Communication tasks such as waiting for commands and sending verification records via laser and other data formats are detailed. GNC-specific algorithms and observations from science circuitry are also covered, ensuring accurate execution and monitoring.
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Deployment • Time to execute pre-launch sequence - • Spin up reaction wheels and get initial attitude and position from Shuttle if possible. • Turn on receiver, if it is not already. • After release • Deploy antennas • Initialize GNC stabilization algorithms • Diagnostics for GNC and Power
Deployment • After release (conti..) • Initial other subsystem algorithms as necessary • When stabilization is achieved • Record all initial attitude and diagnostic data to memory • Wait for initial command sequence from TTC • Execute GNC tasks as necessary
Downlink • Receive contact signal from TTC • Give Bus control to TNC • Note: A pipelined bus might be necessary to achieve 2 Mbit/s data rate • Wait for bus release from TNC.
Laser Communication • Receive signal from LCS circuitry that data is ready to be sent • Receive packet, compute checksum, accept or resend (if Tx is available) • Send verification record to groundstation on next pass.
Lightning observation • Receive lightning observation command from Science circuitry. • Execute any GNC algorithms necessary • Wait to receive Science data via the data bus or DMA • Note: The method of data movement depends on the amount of data (i.e. Low=data bus; High=DMA)
GNC • Receive request from GNC for algorithm execution • Execute the requested algorithm. • If algorithm is ended when a certain position is reached, not depending on time then monitor GNC and set a standard time of execution. • If algorithm is ended on execution time, set watchdog timer.
GNC (conti) • After execution, record new attitude information to memory