Spaceflight Insider

Juno spacecraft goes into safe mode prior to flyby

This artist's rendering shows NASA's Juno spacecraft making one of its close passes over Jupiter. Image Credit: NASA

This artist’s rendering shows NASA’s Juno spacecraft making one of its close passes over Jupiter. Image Credit: NASA

NASA’s Juno spacecraft entered safe mode on Tuesday, October 18, 10:47 p.m. PDT (October 19 at 1:47 a.m. EDT / 05:47 GMT). For reasons that aren’t fully known yet, a software performance monitor induced a reboot of the spacecraft’s onboard computer. Juno restarted successfully and is healthy. High-rate data has been restored and the spacecraft is currently conducting flight software diagnostics. All of the spacecraft’s science instruments are turned off and no science data was collected during Wednesday’s close flyby of Jupiter.

“At the time safe mode was entered, the spacecraft was more than 13 hours from its closest approach to Jupiter,” said Rick Nybakken, Juno project manager from NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “We were still quite a ways from the planet’s more intense radiation belts and magnetic fields. The spacecraft is healthy and we are working our standard recovery procedure.”

The Juno team is also investigating an unrelated issue with the performance of two valves that are part of the spacecraft’s propulsion system. On Friday, mission managers decided to delay the final burn of the spacecraft’s main engine, which was originally scheduled to take place during the close approach of Jupiter on October 19. The burn, called the period reduction maneuver (PRM), would have reduced the spacecraft’s orbital period around Jupiter from 53.4 days to 14 days. The burn was delayed in order to study the performance of a set of valves that are part of Juno’s fuel pressurization system.

“Telemetry indicates that two helium check valves that play an important role in the firing of the spacecraft’s main engine did not operate as expected during a command sequence that was initiated yesterday,” Nybakken said on Friday. “The valves should have opened in a few seconds, but it took several minutes. We need to better understand this issue before moving forward with a burn of the main engine.”

The team decided to postpone the PRM maneuver for at least one orbit after consulting with Lockheed Martin Space Systems in Denver Colorado and NASA Headquarters in Washington, D.C. The most efficient time to perform the PRM burn is during the spacecraft’s closest approach to Jupiter. The next opportunity to perform the burn will be during Juno’s close flyby of the gas giant planet on December 11.

On Wednesday, members of the Juno mission team held a press conference to discuss the status of the mission and recent scientific findings. The briefing took place at the meeting of the American Astronomical Society’s (AAS) Division of Planetary Sciences and European Science Congress (DPS/EPS) at the Pasadena Convention Center in Pasadena. The briefing participants were the following: David Schurr, deputy director of NASA’s Planetary Science Division at NASA Headquarters in Washington; Scott Bolton, Juno principal investigator at the Southwest Research Institute in San Antonio, Texas; and Candice Hansen, JunoCam imaging scientist at the Planetary Science Institute in Tuscon, Arizona.

“We have a couple of tasks of we have to do,” said Bolton. “One, we have to go analyze and understand what just happened with the spacecraft safe-mode entry and make [sure] that that’s all working and understood. And we also are going to go in and look at what was going on with the propulsion system.”

Bolton then discussed the scientific results of Juno’s first close approach of Jupiter, which took place on August 27. Findings from that flyby include that Jupiter’s magnetic fields and aurora are bigger and more powerful than previously thought. Juno’s Microwave Radiometer instrument (MWR) also captured data that provided mission researchers with their first look below the gas giant’s swirling cloud tops. The radiometer instrument can see about 215 to 259 miles (350 to 400 kilometers) below Jupiter’s clouds.

“With the MWR data, it is as if we took an onion and began to peel the layers off to see the structure and processes going on below,” said Bolton. “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.”

This composite image depicts Jupiter’s cloud formations This composite image depicts Jupiter’s cloud formations as seen through the eyes of Juno’s Microwave Radiometer (MWR) instrument as compared to the top layer, a Cassini Imaging Science Subsystem image of the planet. Image Credit: NASA/JPL-Caltech/SwRI/GSFC

This composite image depicts Jupiter’s cloud formations as seen through the eyes of Juno’s Microwave Radiometer (MWR) instrument as compared to the top layer, a Cassini Imaging Science Subsystem image of the planet. Image Credit: NASA / JPL-Caltech / SwRI / GSFC

The JunoCam public outreach camera was also capturing images during the August 27 flyby. All of the raw images taken by JunoCam will be available on the JunoCam website for the public to both view and process into final images. JunoCam is the first outreach camera to travel beyond the asteroid belt.

“JunoCam has a small operations team and no image processing team, so we took a leap of faith that the public would step up and help us generate images of Jupiter from the raw data,” said Candy Hansen, JunoCam imaging scientist from the Planetary Science Institute in Tucson, Arizona. “All sorts of people are coming to the JunoCam site and providing their own aesthetic. We have volunteers from all over the world, and they are doing beautiful work. So far all our expectations for JunoCam have not only been met but are being exceeded, and we’re just getting started.”

The finished images include both straightforward pictures of Jupiter and some with a considerable artistic license, including a variation Vicent Van Gogh’s Starry Night painting and a “smiley face” made from an image of Jupiter’s south pole.

“The amateurs are giving us a different perspective on how to process images,” said Hansen. “They are experimenting with different color enhancements, different highlights or annotations than we would normally expect.  They are identifying storms tracked from Earth to connect our images to the historical record. This is citizen science at its best.”

Juno was launched on August 5, 2011, atop a United Launch Alliance (ULA) Atlas V 551 variant booster from Cape Canaveral Air Station’s Space Launch Complex 41 in Florida and arrived at Jupiter on July 4, 2016. During its close flybys, Juno will peer beneath the giant planet’s cloud cover and study its auroras to learn more about Jupiter’s origins, structure, atmosphere, and magnetosphere.

This image of the sunlit part of Jupiter and its swirling atmosphere was created by a citizen scientist (Alex Mai) using data from Juno’s JunoCam instrument. Image Credit: NASA/JPL-Caltech/SwRI/MSSS/Alex Mai

This image of the sunlit part of Jupiter and its swirling atmosphere was created by a citizen scientist (Alex Mai) using data from Juno’s JunoCam instrument. Image Credit: NASA / JPL-Caltech / SwRI / MSSS / Alex Mai

 

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Jim Sharkey is a lab assistant, writer and general science enthusiast who grew up in Enid, Oklahoma, the hometown of Skylab and Shuttle astronaut Owen K. Garriott. As a young Star Trek fan he participated in the letter-writing campaign which resulted in the space shuttle prototype being named Enterprise. While his academic studies have ranged from psychology and archaeology to biology, he has never lost his passion for space exploration. Jim began blogging about science, science fiction and futurism in 2004. Jim resides in the San Francisco Bay area and has attended NASA Socials for the Mars Science Laboratory Curiosity rover landing and the NASA LADEE lunar orbiter launch.

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