The ESA JUICE (Jupiter Icy Moons Explorer) spacecraft is all set for a Venus gravity-assist flyby on Aug 31, one of the major steps on its long journey to Jupiter.
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The ESA JUICE (Jupiter Icy Moons Explorer) spacecraft is all set for a Venus gravity-assist flyby on Aug 31, one of the major steps on its long journey to Jupiter.
This follows a major anomaly and recovery of comms to the spacecraft, which was lost on Jul 16.
For several days. commands were sent to JUICE, 11 light-minutes away, to reset its comms subsystem, until one succeeded. The root cause was traced to the age old logic problem - a timer counter rollover, sigh!
https://www.esa.int/Enabling_Support/Operations/Juice_team_resolves_anomaly_on_approach_to_Venus
1/n -
The ESA JUICE (Jupiter Icy Moons Explorer) spacecraft is all set for a Venus gravity-assist flyby on Aug 31, one of the major steps on its long journey to Jupiter.
This follows a major anomaly and recovery of comms to the spacecraft, which was lost on Jul 16.
For several days. commands were sent to JUICE, 11 light-minutes away, to reset its comms subsystem, until one succeeded. The root cause was traced to the age old logic problem - a timer counter rollover, sigh!
https://www.esa.int/Enabling_Support/Operations/Juice_team_resolves_anomaly_on_approach_to_Venus
1/nAccording to ESA, "the root cause was traced to a software timing bug. The function that switches the signal amplifier on and off uses an internal timer, which increments and restarts from zero every 16 months. If the function happens to be using the timer at the exact moment it restarts, the amp remains switched off."
Sounds like an unsigned 32-bit counter that counts every 10 ms and rolls over in 497.1 days (~16 months) and some faulty logic like t1 > t0 + delta?
https://www.esa.int/Enabling_Support/Operations/Juice_team_resolves_anomaly_on_approach_to_Venus
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undefined rag. Gustavino Bevilacqua ha condiviso questa discussione
