Computer Glitch Nixes Juno's Run at Jupiter

The next opportunity for observations will be in December.

After a potential engine problem derailed plans for the Juno spacecraft to a tighten up its orbit as it passed close to Jupiter this week, flight controllers decided instead to use the flyby for some early science observations.

But that plan fell apart too when an unrelated computer problem shut down Juno's science instruments 13 hours before Wednesday's close encounter.

"It did exactly what it was supposed to do when it detects a condition that is not expected," Scott Bolton, the project's lead scientist, said at the American Astronomical Society meeting in Pasadena, Calif.

Flight directors at NASA's Jet Propulsion Laboratory in Pasadena are still analyzing why Juno went into what is known as "safe mode."

"Early indications are a software performance monitor induced a reboot of the spacecraft's onboard computer. The spacecraft ... restarted successfully and is healthy," NASA said in a statement.

Juno, which remains in a looping, 53-day orbit around Jupiter, won't pass close by the planet until Dec. 11. At that time, if the engine issue is resolved, Juno could be commanded to trim its orbit so that passes close to Jupiter every 14 days.

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If the problem persists, Juno could conduct its mission from its present orbit, since the primary science observations are made when the spacecraft is closest to Jupiter - whenever that occurs.

"A 53-day orbit has the same value that a 14-day orbit would have ... The difference is how far away you get from Jupiter," Bolton said. "The worst-case scenario is I have to be patient and get the science slowly."

Since arriving at Jupiter on July 4, Juno has had just one previous close encounter, an Aug. 27 flyby allowed the science team to calibrate instruments and cameras.

That work went better than expected, giving scientists some early insights into the planet's magnetic fields and aurora, both bigger and more powerful than previously estimated. They also got a first glimpse of what is happening beneath Jupiter's thick clouds.

"We are seeing that those beautiful belts and bands of orange and white we see at Jupiter's cloud tops extend in some version as far down as our instruments can see, but seem to change with each layer," Bolton said in a statement.

A composite image showing Jupiter's cloud tops and what lies beneath, as seen through the eyes of Juno's Microwave Radiometer instrument. Credit: NASA/JPL-Caltech/SwRI/GSFC WATCH: Juno Has Arrived At Jupiter! Now What?