Juno to Jupiter

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    Interesting alterations to Juno’s Jovian flight plan for next year. [LINK]

    Following a detailed analysis by the Juno team, NASA recently approved changes to the mission’s flight plan at Jupiter. Instead of taking 11 days to orbit the planet, Juno will now complete one revolution every 14 days. The difference in orbit period will be accomplished by having Juno execute a slightly shorter engine burn than originally planned.

    The revised cadence will allow Juno to build maps of the planet’s magnetic and gravity fields in a way that will provide a global look at the planet earlier in the mission than the original plan. Over successive orbits, Juno will build a virtual web around Jupiter, making its gravity and magnetic field maps as it passes over different longitudes from north to south. The original plan would have required 15 orbits to map these forces globally, with 15 more orbits filling in gaps to make the map complete. In the revised plan, Juno will get very basic mapping coverage in just eight orbits. A new level of detail will be added with each successive doubling of the number, at 16 and 32 orbits.

    The slightly longer orbit also will provide a few extra days between close approaches to the planet for the team to react to unexpected conditions the spacecraft might experience in the complex environment very close to Jupiter.

    Interesting timing on this announcement, right after both Dawn and New Horizons went into their own failsafe modes (and of course, Philae’s had a whole set of problems unique to its environment as well). I read this as: “given that we already had one failsafe incident while passing through the comparitively tame magnetic environment around Earth, we’re gonna play it safe – really, really, really safe.”

    Because passing just a few thousand kilometers over Jupiter’s cloudtops once per orbit, Juno is gonna get cooked. The central hub containing the computers and instruments is basically a flying Faraday cage, but Walter White couldn’t cook this thing like Jupiter will. Pioneer 10, the Voyagers and – several times during its tour – Galileo all experienced problems. One of Galileo’s safe mode “blackouts” almost cost us the entire data set related to the moon Amalthea. And even Juno’s instruments aren’t guaranteed to survive its entire tour: its onboard camera is only expected to survive seven of those close passes of Jupiter before it’s too fried to function.

    After the required, seven orbit design life, Junocam will continue to operate as long as possible in the harsh jovian radiation environment.

    They’re expecting harshness… and if they’ve altered the flight plan in mid-flight to ensure that they get a bare-minimum “safety” data set as quickly as possible, it sounds like they’ve run the numbers and found maybe they didn’t expect enough harshness. And the recent safe mode incidents of other spacecraft may have spooked them as well.

    I’m really looking forward to this mission… and I’m hoping it doesn’t turn out to be another diminished-expectations mission like Galileo was (due to the failure of its high gain antenna to open).


    The Twitter account for the Juno mission reports that we should start expecting some far-approach JunoCam images soon; Juno’s eye is open and it’s looking for Jupiter.


    From today’s press release [LINK]…open up an say AAH, Juno!

    As of Thursday, Juno is 18 days and 8.6 million miles (13.8 million kilometers) from Jupiter. On the evening of July 4, Juno will fire its main engine for 35 minutes, placing it into a polar orbit around the gas giant. During the flybys, Juno will probe beneath the obscuring cloud cover of Jupiter and study its auroras to learn more about the planet’s origins, structure, atmosphere and magnetosphere.

    The source of potential trouble can be found inside Jupiter itself. Well below the Jovian cloud tops is a layer of hydrogen under such incredible pressure it acts as an electrical conductor. Scientists believe that the combination of this metallic hydrogen along with Jupiter’s fast rotation — one day on Jupiter is only 10 hours long — generates a powerful magnetic field that surrounds the planet with electrons, protons and ions traveling at nearly the speed of light. The endgame for any spacecraft that enters this doughnut-shaped field of high-energy particles is an encounter with the harshest radiation environment in the solar system.

    “Over the life of the mission, Juno will be exposed to the equivalent of over 100 million dental X-rays,” said Rick Nybakken, Juno’s project manager from NASA’s Jet Propulsion Laboratory in Pasadena, California. “But, we are ready. We designed an orbit around Jupiter that minimizes exposure to Jupiter’s harsh radiation environment. This orbit allows us to survive long enough to obtain the tantalizing science data that we have traveled so far to get.”

    While Juno is replete with special radiation-hardened electrical wiring and shielding surrounding its myriad of sensors, the highest profile piece of armor Juno carries is a first-of-its-kind titanium vault, which contains the spacecraft’s flight computer and the electronic hearts of many of its science instruments. Weighing in at almost 400 pounds (172 kilograms), the vault will reduce the exposure to radiation by 800 times of that outside of its titanium walls.

    Without the vault, Juno’s electronic brain would more than likely fry before the end of the very first flyby of the planet. But, while 400 pounds of titanium can do magical things, it can’t do it forever in an extreme radiation environment like that on Jupiter. The quantity and energy of the high-energy particles is just too much. However, Juno’s special orbit allows the radiation dose and the degradation to accumulate slowly, allowing Juno to do a remarkable amount of science for 20 months.

    “Over the course of the mission, the highest-energy electrons will penetrate the vault, creating a spray of secondary photons and particles,” said Heidi Becker of JPL, Juno’s Radiation Monitoring Investigation lead. “The constant bombardment will break the atomic bonds in Juno’s electronics.”

    😯 I’m sure the degradation in performance will be watched closely, because between ESA and NASA, there will be a couple of robots headed to Europa in the next 20 years. If there are space fishies swimming around under Europa’s ice crust, they’re gonna be really, really radioactive space fishies.


    In case you hadn’t heard already, Juno’s hair-raising approach was a 100% success. [LINK]

    NASA’s Juno spacecraft successfully entered Jupiter’s orbit during a 35-minute engine burn. Confirmation that the burn had completed was received on Earth at 8:53 p.m. PDT (11:53 p.m. EDT) Monday, July 4.

    “Independence Day always is something to celebrate, but today we can add to America’s birthday another reason to cheer — Juno is at Jupiter,” said NASA administrator Charlie Bolden. “And what is more American than a NASA mission going boldly where no spacecraft has gone before? With Juno, we will investigate the unknowns of Jupiter’s massive radiation belts to delve deep into not only the planet’s interior, but into how Jupiter was born and how our entire solar system evolved.”

    Confirmation of a successful orbit insertion was received from Juno tracking data monitored at the navigation facility at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, as well as at the Lockheed Martin Juno operations center in Littleton, Colorado. The telemetry and tracking data were received by NASA’s Deep Space Network antennas in Goldstone, California, and Canberra, Australia.

    “This is the one time I don’t mind being stuck in a windowless room on the night of the 4th of July,” said Scott Bolton, principal investigator of Juno from Southwest Research Institute in San Antonio. “The mission team did great. The spacecraft did great. We are looking great. It’s a great day.”

    Preplanned events leading up to the orbital insertion engine burn included changing the spacecraft’s attitude to point the main engine in the desired direction and then increasing the spacecraft’s rotation rate from 2 to 5 revolutions per minute (RPM) to help stabilize it..

    The burn of Juno’s 645-Newton Leros-1b main engine began on time at 8:18 p.m. PDT (11:18 p.m. EDT), decreasing the spacecraft’s velocity by 1,212 miles per hour (542 meters per second) and allowing Juno to be captured in orbit around Jupiter. Soon after the burn was completed, Juno turned so that the sun’s rays could once again reach the 18,698 individual solar cells that give Juno its energy.

    “The spacecraft worked perfectly, which is always nice when you’re driving a vehicle with 1.7 billion miles on the odometer,” said Rick Nybakken, Juno project manager from JPL. “Jupiter orbit insertion was a big step and the most challenging remaining in our mission plan, but there are others that have to occur before we can give the science team the mission they are looking for.”

    Over the next few months, Juno’s mission and science teams will perform final testing on the spacecraft’s subsystems, final calibration of science instruments and some science collection.

    “Our official science collection phase begins in October, but we’ve figured out a way to collect data a lot earlier than that,” said Bolton. “Which when you’re talking about the single biggest planetary body in the solar system is a really good thing. There is a lot to see and do here.”

    I stayed up late to watch this in real time, and it was fairly tense stuff. Whatever happened, by the time we got a signal about it on Earth, had happened 48 minutes before with absolutely no chance for intervention. That they nailed the whole maneuver completely – the engine needed for fire for 20 minutes solid to put Juno into an orbit around Jupiter, but 35 minutes to put it in the right orbit, and in the end the engine stopped firing one second early – is just astounding. I’ve been kinda Juno/Jupiter-happy on Facebook of late, and a few folks private messaged me saying “enough with the space stuff!”, but what they don’t get is that…this is really the Super Bowl of smart. It’s my payback for quietly scrolling past their sports and pro-Trump memes.

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    Pretty cool stuff. I didn’t realize, until this past weekend, that Juno is only the second Jupiter probe to orbit the planet. I also found out (earlier today) that Juno was the first mission to Jupiter using solar panels because it was a victim of the Pu-238 shortage during that time (technically we still have the shortage but DOE started production back in December of last year).

    I was also the victim of misinformation this morning. Someone on the radio or TV (I can’t remember) said that the probe was huge: bigger than a football field. “That can’t be”, I thought, “That would make it as big as the ISS”. It’s not that big. Its span is only 20 meters wide. That’s big but not football field sized big.

    …and a few folks private messaged me saying “enough with the space stuff!”

    Really? People are actually complaining about that? With all the “I love God/look at my puppies/cute kitten pics/my baby is sooo cute/video games are awesome/Sothy sarcasm/look what I did on my recent trip” crap I see on a daily basis (to say nothing about all the knitting related posts I see) , your Juno posts are nothing but a minor blip on my radar.

    Steve W
    Steve W
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    I’d heard that “bigger than a football field” thing too. Which would make it the largest thing ever launched into space. It’d be a lot of effort to launch with the weight of something like that, unless it was made of styrofoam.


    So this Saturday morning, not content to sit back and watch cartoons, Juno will buzz Jupiter’s cloudtops at an altitude of roughly the distance from West Virginia to Nevada. [LINK] And best of all: eyes open this time.

    This Saturday at 5:51 a.m. PDT, (8:51 a.m. EDT, 12:51 UTC) NASA’s Juno spacecraft will get closer to the cloud tops of Jupiter than at any other time during its prime mission. At the moment of closest approach, Juno will be about 2,500 miles (4,200 kilometers) above Jupiter’s swirling clouds and traveling at 130,000 mph (208,000 kilometers per hour) with respect to the planet. There are 35 more close flybys of Jupiter scheduled during its prime mission (scheduled to end in February of 2018). The Aug. 27 flyby will be the first time Juno will have its entire suite of science instruments activated and looking at the giant planet as the spacecraft zooms past.

    “This is the first time we will be close to Jupiter since we entered orbit on July 4,” said Scott Bolton, principal investigator of Juno from the Southwest Research Institute in San Antonio. “Back then we turned all our instruments off to focus on the rocket burn to get Juno into orbit around Jupiter. Since then, we have checked Juno from stem to stern and back again. We still have more testing to do, but we are confident that everything is working great, so for this upcoming flyby Juno’s eyes and ears, our science instruments, will all be open.”

    “This is our first opportunity to really take a close-up look at the king of our solar system and begin to figure out how he works,” Bolton said.

    While the science data from the pass should be downlinked to Earth within days, interpretation and first results are not expected for some time.



    Remember when Juno went into safe mode in October and totally blew one of its precious close passes of Jupiter? It turns out there’s a gremlin aboard the spacecraft. [LINK]

    Juno went into safe mode about 13 hours before an Oct. 19 close approach to Jupiter, the second such approach since Juno entered orbit around the planet in July. The safe mode prevented the spacecraft’s science instruments from collecting data during the flyby. Juno exited safe mode five days later.

    Speaking at the Fall Meeting of the American Geophysical Union (AGU) in San Francisco, the mission’s principal investigator, Scott Bolton of the Southwest Research Institute, said the safe mode was triggered by an issue with transferring data one of the spacecraft’s instruments, the Jupiter Infrared Auroral Mapper (JIRAM).

    “It went into safe mode and it was related to JIRAM data, the transfer across the bus of the spacecraft,” Bolton said. “There was nothing actually wrong with JIRAM and it had to do with something in the spacecraft.”

    Bolton said that engineers have developed a software patch to correct the problem, but have yet to install on Juno’s computers. As a result, JIRAM was not turned on during Juno’s latest close approach to Jupiter on Dec. 11.


    Will NASA dare mighty things with the only thing in orbit around Jupiter? [LINK]

    As NASA’s Juno spacecraft prepares for another close approach to Jupiter, the agency expects to make a decision in February about when, or if, to perform a delayed maneuver to adjust its orbit.

    Juno, which entered orbit around Jupiter July 4, was to perform what the mission called a “period reduction maneuver” on Oct. 19, firing its main engine to shorten the period of its orbit from 53 to 14 days. NASA postponed that maneuver several days before it was scheduled because of a problem with helium valves in the spacecraft’s propulsion system. Agency officials later said they were investigating any commonality between Juno’s engine and the orbit-raising engine on a commercial communications satellite that failed after launch last September.

    That maneuver, designed to be performed when the spacecraft is closest to Jupiter in its elliptical orbit, was not performed during Juno’s next close approach Dec. 11. A NASA statement Jan. 19 about plans for the next flyby, on Feb. 2, made no mention of any plans for the maneuver.

    In a Jan. 20 statement to SpaceNews, David Schurr, deputy director of NASA’s planetary science division, said a decision on whether or not to reschedule the maneuver will be made next month.

    “The health of the propulsion system remains under evaluation, and NASA expects to make a decision in February as to whether or not we will schedule an additional [period reduction maneuver] burn,” he said.

    I hadn’t heard this “faulty family of engines” angle before, so I tracked down another story on the subject [LINK]…

    “It was made known to us that the rocket we currently have on Juno, the retrorocket that gets us into orbit, is in the same family as one that has been malfunctioning on the Intelsats,” he said.

    He was referring to Intelsat 33e, a Boeing 702MP satellite launched in August. On Sept. 9, Intelsat announced that the spacecraft’s entry into service in geostationary orbit would be delayed from fourth quarter of 2016 to the first quarter of 2017 because of a thruster malfunction. That model of satellite uses a Leros engine, manufactured by Moog, to raise its orbit after deployment.

    While Juno uses a different version of the Leros engine than the one on Intelsat 33e, and launched five years earlier, Green said engineers were investigating whether there may be any links between the two. “Whenever that happens, we step back and take a good look at what we have, how it’s implemented, look at the failure modes for these similar things,” he said, “and then do an analysis on what we’re going to do next and what the probability is of what we have on our spacecraft failing.”

    Oooops. Guess I can’t razz the Russians about faulty rockets anymore.

    Steve W
    Steve W
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    I should be more interested in this, but my takeaway from this article;

    That model of satellite uses a Leros engine, manufactured by Moog, to raise its orbit after deployment.

    Moog now makes rocket engines?


    One million pounds of thrust + kickass ELP synth solos. Who doesn’t want that combination?

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    And if the Leros engine fails, everyone at the company would suffer from the Moogy Blues.



    NASA elects not to dare too many mighty things with the only thing in orbit around Jupiter. [LINK]

    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 science 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.

    Juno will probably last longer in this orbit as well, spending less time in Jupiter’s rough electromagnetic neighborhood. Remember that the huge delay in Japan’s Akatsuki mission to Venus was a result of firing up an engine that proceeded to blow itself, and probably the back half of the spacecraft, to pieces. Let’s not do that with Juno.

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    Holy cow. SCIENCE! [LINK]


    “We knew, going in, that Jupiter would throw us some curves,” said Scott Bolton, Juno principal investigator from the Southwest Research Institute in San Antonio. “But now that we are here we are finding that Jupiter can throw the heat, as well as knuckleballs and sliders. There is so much going on here that we didn’t expect that we have had to take a step back and begin to rethink of this as a whole new Jupiter.”

    Among the findings that challenge assumptions are those provided by Juno’s imager, JunoCam. The images show both of Jupiter’s poles are covered in Earth-sized swirling storms that are densely clustered and rubbing together.


    “We’re puzzled as to how they could be formed, how stable the configuration is, and why Jupiter’s north pole doesn’t look like the south pole,” said Bolton. “We’re questioning whether this is a dynamic system, and are we seeing just one stage, and over the next year, we’re going to watch it disappear, or is this a stable configuration and these storms are circulating around one another?”

    Another surprise comes from Juno’s Microwave Radiometer (MWR), which samples the thermal microwave radiation from Jupiter’s atmosphere, from the top of the ammonia clouds to deep within its atmosphere. The MWR data indicates that Jupiter’s iconic belts and zones are mysterious, with the belt near the equator penetrating all the way down, while the belts and zones at other latitudes seem to evolve to other structures. The data suggest the ammonia is quite variable and continues to increase as far down as we can see with MWR, which is a few hundred miles or kilometers.


    “Juno is giving us a view of the magnetic field close to Jupiter that we’ve never had before,” said Jack Connerney, Juno deputy principal investigator and the lead for the mission’s magnetic field investigation at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Already we see that the magnetic field looks lumpy: it is stronger in some places and weaker in others. This uneven distribution suggests that the field might be generated by dynamo action closer to the surface, above the layer of metallic hydrogen. Every flyby we execute gets us closer to determining where and how Jupiter’s dynamo works.”


    “Every 53 days, we go screaming by Jupiter, get doused by a fire hose of Jovian science, and there is always something new,” said Bolton. “On our next flyby on July 11, we will fly directly over one of the most iconic features in the entire solar system — one that every school kid knows — Jupiter’s Great Red Spot. If anybody is going to get to the bottom of what is going on below those mammoth swirling crimson cloud tops, it’s Juno and her cloud-piercing science instruments.”


    And just for giggles, here’s Juno’s view of Jupiter’s rings…from between the rings and the planet, looking out.


    (All of the images in this post are zoomable.)

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    Juno Perijove 06 preview

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