[meteorite-list] Juno Is In Safe Mode, But Okay and On Course Following Earth Flyby

[Ron Baalke]

http://www.planetary.org/blogs/emily-lakdawalla/2013/10091550-juno-safe-mode.html

Juno is in safe mode, but okay and on course following Earth flyby
By Emily Lakdawalla
Planetary Society Blog
October 9, 2013

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.

Launching from Earth in 2011, the Juno spacecraft will arrive at Jupiter 
in 2016 to study the giant planet from an elliptical, polar orbit. Juno 
will repeatedly dive between the planet and its intense belts of charged 
particle radiation, coming only 5,000 kilometers from the cloud tops at 
closest approach.