Juno to remain in current orbit at Jupiter

February 19, 2017, NASA
NASA's Juno spacecraft soared directly over Jupiter's south pole when JunoCam acquired this image on February 2, 2017 at 6:06 a.m. PT (9:06 a.m. ET), from an altitude of about 62,800 miles (101,000 kilometers) above the cloud tops. Credit: NASA

NASA's Juno mission to Jupiter, which has been in orbit around the gas giant since July 4, 2016, will remain in its current 53-day orbit for the remainder of the mission. This will allow Juno to accomplish its science goals, while avoiding the risk of a previously-planned engine firing that would have reduced the spacecraft's orbital period to 14 days.

"Juno is healthy, its instruments are fully operational, and the data and images we've received are nothing short of amazing," said Thomas Zurbuchen, associate administrator for NASA's Science Mission Directorate in Washington. "The decision to forego the burn is the right thing to do—preserving a valuable asset so that Juno can continue its exciting journey of discovery."

Juno has successfully orbited Jupiter four times since arriving at the giant planet, with the most recent orbit completed on Feb. 2. Its next close flyby of Jupiter will be March 27.

The orbital period does not affect the quality of the science collected by Juno on each flyby, since the altitude over Jupiter will be the same at the time of closest approach. In fact, the longer orbit provides new opportunities that allow further exploration of the far reaches of space dominated by Jupiter's magnetic field, increasing the value of Juno's research.

During each orbit, Juno soars low over Jupiter's cloud tops—as close as about 2,600 miles (4,100 kilometers). During these flybys, Juno probes beneath the obscuring cloud cover and studies Jupiter's auroras to learn more about the planet's origins, structure, atmosphere and magnetosphere.

The original Juno flight plan envisioned the spacecraft looping around Jupiter twice in 53-day orbits, then reducing its orbital period to 14 days for the remainder of the mission. However, two helium check valves that are part of the plumbing for the spacecraft's did not operate as expected when the propulsion system was pressurized in October. Telemetry from the spacecraft indicated that it took several minutes for the valves to open, while it took only a few seconds during past main engine firings.

"During a thorough review, we looked at multiple scenarios that would place Juno in a shorter-period orbit, but there was concern that another main engine burn could result in a less-than-desirable orbit," said Rick Nybakken, Juno project manager at NASA's Jet Propulsion Laboratory in Pasadena, California. "The bottom line is a burn represented a risk to completion of Juno's science objectives."

Juno's larger 53-day orbit allows for "bonus science" that wasn't part of the original mission design. Juno will further explore the far reaches of the Jovian magnetosphere—the region of space dominated by Jupiter's magnetic field—including the far magnetotail, the southern magnetosphere, and the magnetospheric boundary region called the magnetopause. Understanding magnetospheres and how they interact with the solar wind are key science goals of NASA's Heliophysics Science Division.

"Another key advantage of the longer orbit is that Juno will spend less time within the strong radiation belts on each ," said Scott Bolton, Juno principal investigator from Southwest Research Institute in San Antonio. "This is significant because radiation has been the main life-limiting factor for Juno."

Juno will continue to operate within the current budget plan through July 2018, for a total of 12 science orbits. The team can then propose to extend the mission during the next science review cycle. The review process evaluates proposed mission extensions on the merit and value of previous and anticipated science returns.

The Juno science team continues to analyze returns from previous flybys. Revelations include that Jupiter's magnetic fields and aurora are bigger and more powerful than originally thought and that the belts and zones that give the gas giant's cloud top its distinctive look extend deep into the planet's interior. Peer-reviewed papers with more in-depth science results from Juno's first three flybys are expected to be published within the next few months. In addition, the mission's JunoCam—the first interplanetary outreach camera—is now being guided with assistance from the public. People can participate by voting on which features on Jupiter should be imaged during each flyby.

"Juno is providing spectacular results, and we are rewriting our ideas of how giant planets work," said Bolton. "The science will be just as spectacular as with our original plan."

Explore further: NASA's Juno spacecraft to make its fourth flyby over Jupiter

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Frosted Flake
5 / 5 (6) Feb 19, 2017
Good decision. Thank you. Please keep this mission going until Juno fails. At this point a little more money to monitor data is a penny after a pound.
2.1 / 5 (7) Feb 19, 2017
Don't know about the data, but the pics are spectacular.
1 / 5 (1) Feb 19, 2017
Doesn't look bright enough to be seen all the way from Earth, must be a short exposure.
not rated yet Feb 20, 2017
This article sounds a little too rosy. If this orbit is better and allows for "bonus" science, why wasn't it the original plan? I'm happy JUNO is still working and that it will deliver most or all of its science goals, but surely there are downsides. I believe one is that later in the orbit it will be eclipsed by Jupiter and may not have enough power?

I agree with Frosted Flake though, no reason at all not to continue this mission for as long as possible. Would it be feasible to attempt another engine burn in 18 months, or will the fuel or other parts have degraded by then?
1 / 5 (10) Feb 20, 2017
Earth is flat and motionless. There is no outer space. Don't be fooled by the occult fraudsters. Water lays flat it always finds its level. The horizon is flat and eyelevel up at 25 miles and at sea level. There is no curvature. Your own senses and science proves earth is not a spinning sphere with oceans on its surface and an atmosphere flying through a vacuum. That is physically impossible. If that was true you would be able to demonstrate a small scale example of that. They show you CGI, photoshop, animation, special effects and lie to you. Only a fool believes their falsehood. The sun moon and stars are lights that move around above the atmosphere.
5 / 5 (4) Feb 20, 2017
Flat earth, nonsense. You don't believe what you wrote, you are trying to amuse yourself trolling crap you hope will get a response so you can put up more nonsense you don't believe. (Yeah, I'm guilty of doing what you want except I'm not wasting time showing how wrong your claims are because I know you don't really believe them.)
5 / 5 (2) Feb 21, 2017
Flat-earth trolling on science websites...now there's a job that artificial un-intelligence could do just as well as a human being! Waste of time even replying...
1 / 5 (1) Feb 26, 2017
Well i am an astronaut and the last time i was at the space station i can tell you it certainly looked round so i can state unequivocally that the earth is round.

It was leaking a little around the edges but we are taught to ignore that.
1 / 5 (1) Feb 26, 2017
Hmmm, seems the mission people failed to properly account for the plasma environment at Jupiter, can't imagine why....

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