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NASA's $1 Billion Jupiter Probe Has Suffered 2 Big Problems In 2 Days

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Dave Mosher

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NASA's tennis court-size Juno probe is in a bit of a sticky situation 600 million miles from Earth.

Just days before Juno swooped by Jupiter on Wednesday morning — its second 130,000 mph flyby since August 27 — the spacecraft experienced two significant glitches.


One of those problems prevented the $1.1 billion probe from taking new photos, recording auroras, and logging other crucial data about the gas giant, mission managers said during an American Astronomical Society (AAS) press briefing on Wednesday.

The other could lengthen the planned mission from February 2018 (when it's supposed to plunge into the clouds of Jupiter and die) by an additional one or two years.

Going into safe mode

An illustration of NASA's Juno spacecraft flying through the radiation belts of Jupiter. NASA/JPL-Caltech


"On the way in [Tuesday] night, the spacecraft went into safe mode," Scott Bolton, a planetary scientist at the Southwest Research Institute in San Antonio and the Juno mission's leader, said during the AAS briefing.

"It detected a condition that was not expected ... and it did exactly what it was supposed to do," Bolton said

He noted that a space probe's safe mode is an act of self-preservation, and in this case the software turned off Juno's cameras and other science instruments, pointed itself toward the sun, and waited "for direction from the humans back home."

Fortunately, NASA said in an Oct. 19 press release, the probe is healthy and its Earth-based operators are working to restore Juno to a full functionality.


What caused the spacecraft to reset itself?

Bolton told Business Insider and other reporters who tuned into the conference that he wasn't sure.

"It's too early to take a guess," Bolton said, later adding: "My instinct is that it wasn't caused by the intense radiation belts that we're so fearful of," since the glitch occurred some 13 hours from Juno's closest approach to the cloud tops of Jupiter.

Sticky engine valves


Like an automobile on a blisteringly cold morning, Juno is having engine troubles, too.

A firing of the probe's main engine on October 19 was supposed to dramatically shorten Juno's 53-day elliptical orbits around Jupiter to just 2 weeks — a move that would have sped of NASA's study of Jupiter by nearly four-fold.


However, during a routine test, the spacecraft's operators noticed a problem: Two valves that pressurize the engine before firing were operating sluggishly, Bolton told reporters on Wednesday.

"Maybe the valves were a little sticky," he said. "We decided to postpone and delay that burn" to find the source of the problem, Bolton added.


According to an Oct. 13 NASA press release about the issue, the next chance for Juno to fire its thruster will be Dec. 11 — right before its third perijove, or closest pass, of Jupiter.

At worst, Bolton said the Juno team won't ever fire the engine, and everyone will just have to be more patient.

"But the science opportunities are all there," he said.

Peeking beneath the cloud tops


A peek under Jupiter's clouds, as visualized from Juno spacecraft data. NASA/JPL-Caltech/SwRI/GSFC

Aside from regaling reporters on Juno's troubles, which seem recoverable, if not a little bit annoying, researchers took a moment to highlight new research from Juno's first pass by the gas giant on August 27.

The above image is a visualization of data gathered by Juno's microwave radiometer, when is designed to "peel the layers back as if Jupiter is an onion," Bolton said.

He emphasized that this beyond-surface level view of Jupiter, let alone any gas giant, is unprecedented in the history of space exploration.


"The structures of the zones and belts still exist deep down into Jupiter," Bolton said, but noted they seem to be twisting and evolving. "That came as a surprise to many scientists. We didn't know if this was skin-deep. ... Deep down, Jupiter is similar but also very different than what we see on the surface."

In addition to sharing the new image, Candice Hansen, an imaging scientist at the Planetary Science Institute in Tucson, Arizona, showed off a few Juno images that "citizen scientists" processed using raw data.

This view, which its creator dubbed "Jupiterrise," shows a false-color view of Jupiter's South Pole that helps its roiling cyclones stand out:

A false-color image of Jupiter's North Pole. NASA/JPL-Caltech/SwRI/MSSS/Alex Mai


And this image was re-processed to point out the Earth-size storms on Jupiter in a different way:

Earth-size storms on Jupiter's South Pole. NASA/SwRI/MSSS/Roman Tkachenko

Another user had a little fun, mirroring the visible half of Jupiter and coloring it yellow to make a smiley face:

NASA/JPL-Caltech/SwRI/MSSS/Randy Ahn


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