The Problem and Solution of a Twice-a-Day Frame Loss in Galileo's Telemetry
M. Belongie, Jim Taylor, David H. Rogstad, R. Lee · 1996
for the flrst time. The in-°ight Galileo spacecraft operated for the flrst time its newly loaded science virtual machine software to produce Phase 2 packet telemetry, and the Deep Space Communications Complex (DSCC) Galileo telemetry (DGT) subsystem received and processed this downlink format from the spacecraft [1]. Pre-viously, the spacecraft packet data stream had been simulated in the project testbed at JPL, and the DGT had received the Phase 1 time division multiplex telemetry from the spacecraft. The transmission of a complex new spacecraft data format to a wholly new ground receiving system proceeded smoothly until the unexpected loss (undecodability) of a Reed{Solomon transfer frame that occurred on May 24. On subsequent days, additional frames were lost, in a soon predictable twice-a-day pattern. This article documents how a team, consisting of individuals from the DGT de-velopment organization, the Deep Space Network (DSN) operations and analysis