Juno is in safe mode, but okay and on course following Earth flyby
Posted by Emily Lakdawalla
09-10-2013 17:56 CDT
Following its Earth flyby earlier today, Juno is in safe mode. This is the protective state a spacecraft goes into when it detects a problem. But everything is okay.
For more details, I just spoke with Rick Nybakken, Juno Project Manager at the Jet Propulsion Laboratory. For a bit of background: as Juno flew past Earth, it spent some time in Earth's shadow, that is, "in eclipse." Nybakken told me that Juno entered eclipse in a nominal state, and came out of eclipse in safe mode. He said they have established communications with the vehicle, and that they have full commandability, and that they are in a safe, stable state. They don't know what caused the safe mode yet; they have to analyze the telemetry further.
The gravity-assist flyby was a totally passive event in terms of propulsion for the spacecraft, so the safe mode has no effect whatsoever on Juno's planned trajectory; it's on its way to Jupiter. Nybakken told me they hit the target within 2 kilometers.
I asked him if he knows if the planned Earth imaging took place. He said they don't know yet, as they're still analyzing the telemetry they're getting from the spacecraft; he said he hoped they'd know tonight or early tomorrow morning.
I will update you all as I learn more. Safe modes during gravity assists are not unheard of -- because it's a passive event, they don't disable fault protection as they would for, say, an orbit insertion burn. And a gravity assist flyby is a highly unusual event for a spacecraft. It'd be nice if it hadn't happened, but not a great concern that it did, and Nybakken sounded calm.