{"id":15397,"date":"2016-07-04T01:02:17","date_gmt":"2016-07-03T17:02:17","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/nasas-juno-mission-is-about-to-peel-back-the-layers-on-jupiter\/"},"modified":"2016-07-04T01:02:17","modified_gmt":"2016-07-03T17:02:17","slug":"nasas-juno-mission-is-about-to-peel-back-the-layers-on-jupiter","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/nasas-juno-mission-is-about-to-peel-back-the-layers-on-jupiter\/","title":{"rendered":"NASA\u2019s Juno mission is about to peel back the layers on Jupiter"},"content":{"rendered":"

A version of this story was originally published in Astronomy Now magazine.<\/em><\/strong><\/p>\n

\"juno_approach_lm\"
NASA\u2019s Juno spacecraft, seen here in an artist\u2019s illustration, will become the second mission to orbit the solar system\u2019s king planet. Credit: Lockheed Martin<\/figcaption><\/figure>\n

Whether you\u2019re a casual stargazer or armed with a toolkit of observing gadgets, chances are you have caught a glimpse of Jupiter this year beckoning as one of the brightest objects in the night sky.<\/p>\n

It\u2019s about to get its first visitor in nearly a decade.<\/p>\n

Scott Bolton has also taken in Jupiter over the last few months, but he\u2019s still biding his time. He knows the view is about to get a lot better.<\/p>\n

\u201cI have a lot of friends asking, \u2018Did you see Jupiter tonight?\u2019 I\u2019m like, \u2018Yeah, but I\u2019m waiting for the close-up,’\u201d he said.<\/p>\n

Bolton leads the science team for NASA\u2019s Juno mission, a $1.1 billion project to trace the origin of Jupiter, study the huge planet\u2019s deep interior, and observe the gas giant\u2019s turbulent atmosphere.<\/p>\n

Named for the wife of Jupiter in Roman mythology, a figure who could see through the cloak of clouds kept by the chief deity, Juno will reveal the gaseous world\u2019s poles in detail for the first time. The planet\u2019s high latitudes were mostly hidden from previous probes to Jupiter, which concentrated their observations near the equator. Earlier missions also left open questions about the inner workings of Jupiter, and instead focused on taking pictures and surveying the planet\u2019s many moons.<\/p>\n

Lessons learned at Jupiter can be applied throughout the solar system, and even elsewhere across the cosmos, said Steven Levin, Juno\u2019s project scientist at NASA\u2019s Jet Propulsion Laboratory in Pasadena, California.<\/p>\n

\u201cJupiter is, by far, the largest planet in the solar system,\u201d Levin said. \u201cIt has an influence on everything else. If we want to understand how planets form and how solar systems form, we really have to start with Jupiter.\u201d<\/p>\n

Jupiter likely formed before the other planets, with more than twice the mass of all the other matter in the solar system besides the sun. It has a diameter of 86,881 miles (139,822 kilometers) and is 318 times more massive than Earth, containing 1,321 times the volume of our home planet.<\/p>\n

The solar-powered Juno spacecraft, shaped like a giant three-blade propeller that spans 65 feet (20 meters) across, departed from Earth on Aug. 5, 2011, aboard an Atlas 5 rocket from Cape Canaveral. It took five years to complete the journey, which spanned 1.7 billion miles (2.8 billion kilometers) from liftoff to Juno\u2019s scheduled arrival in orbit around Jupiter on July 4.<\/p>\n

Bolton proposed the Juno concept in 2004, and a year later NASA selected the Jupiter probe over a planned robotic mission to return rock samples to Earth from the far side of the moon.<\/p>\n

\u201cI looked at the schedule and said, \u2018Oh, my God, I\u2019ll be so old when we get to Jupiter,’\u201d says Bolton. \u201cAnd now I\u2019m that old.\u201d<\/p>\n

\"Scott
Scott Bolton, Juno principal investigator. Credit: NASA\/Aubrey Gemignani<\/figcaption><\/figure>\n

Juno will ride into orbit with the help of a make-or-break 35-minute main engine burn, kicking off a highly-choreographed, nearly two-year campaign of scientific research before charged particles surrounding Jupiter take a toll on the spacecraft, eventually giving the probe\u2019s electronics a lethal dose of radiation.<\/p>\n

The probe will be speeding at more than 41 miles per second \u2014 150,000 mph (241,000 kilometers per hour) \u2014 relative to Earth when it arrives at Jupiter. The humongous world\u2019s gravity will tug on Juno during final approach, making it the fastest human-made object in history compared to its home planet, said Bolton, a space physicist based at the Southwest Research Institute in San Antonio, Texas.<\/p>\n

Engineers should receive confirmation of the start of the critical rocket burn at 11:18 p.m. EDT Monday (0318 GMT Tuesday), and Juno should broadcast a tone at the end of the firing 35 minutes later.<\/p>\n

Juno will first enter a preliminary path around Jupiter, taking it several million miles from the planet on an orbit that will take 53 days to complete. Mission planners expect Juno to spend more than three months in that orbit, then adjust down to a lower altitude Oct. 19.<\/p>\n

That is when the probe will commence full-up science observations, employing nine instruments and 29 individual sensors, including a visible camera technically counted as a public outreach tool and not a science payload. In all, Juno will circle Jupiter 37 times before ditching in Jupiter\u2019s atmosphere in February 2018 to end the mission.<\/p>\n

Juno is set to become the second spacecraft to survey Jupiter from orbit after NASA\u2019s Galileo mission ended its science campaign in 2003. Researchers got their last close look at Jupiter in 2007, when the New Horizons probe flew by on the way to Pluto.<\/p>\n

\u201cThere are still an amazing number of basic questions that we don\u2019t have answered about Jupiter, and that\u2019s because it\u2019s hard,\u201d Levin said. \u201cWhen you look at Jupiter, most of what you\u2019re seeing is the very tops of the clouds in Jupiter\u2019s enormous atmosphere. We have basic questions, like how did Jupiter form? What is its composition?\u201d<\/p>\n

Juno will dip inside Jupiter\u2019s radiation belt for most of its mission, but the planet\u2019s uneven gravity will gradually, irreversibly shift the craft\u2019s orbital path, subjecting it to the damaging effects of charged particles suspended in the planet\u2019s magnetic field.<\/p>\n

To top it off, the spacecraft, manufactured by Lockheed Martin is spinning once every 30 seconds, providing stability and ensuring instruments mounted around the edges of Juno\u2019s main body get regular looks at Jupiter.<\/p>\n

\"Credit:
This artist\u2019s concept shows Juno\u2019s approach path toward Jupiter for the July 4 insertion maneuver. Jupiter\u2019s intense radiation belts are also illustrated here. Credit: NASA\/JPL-Caltech<\/figcaption><\/figure>\n

Juno is the first spacecraft to rely on solar power at Jupiter\u2019s distance from the sun \u2014 five times farther away than Earth \u2014 paving the way for future missions that could use solar arrays instead of more complex, and costly, nuclear power generators.<\/p>\n

\u201cWe go in sort of like a dive bomber,\u201d Bolton said. \u201cWe go in really fast and get out fast. That speed itself is really hazardous, and we\u2019re also spinning. We\u2019re this giant solar array spacecraft cartwheeling through this incredible magnetic field and radiation belt. It\u2019s a little bit scary.\u201d<\/p>\n

Each pass close to Jupiter will take Juno about 3,100 miles (5,000 kilometers) above the planet\u2019s colourful clouds, yielding a few hours of up-close observations before the probe climbs millions of kilometres in its ultimate science orbit. Juno will downlink science data to Earth when it is far from Jupiter, then prepare for the next close approach, or perijove.<\/p>\n

Levin likens each perijove as a distinct flyby event because of the short period of time available for premium data collection.<\/p>\n

Managers changed Juno\u2019s flight plan after its launch, settling on a final operational orbit lasting 14 days, three days longer than initially envisioned. Scientists say the new plan allows Juno to complete a first look at meeting the mission\u2019s science goals in shorter time than previously anticipated. But it means Juno will need 20 months, five months longer than originally planned, to collect the mission\u2019s full data set.<\/p>\n

\u201cPart of it was to give us three days to recover and analyze anything that might happen, so we don\u2019t lose another perijove,\u201d Bolton said. \u201cPerijoves are the part of the orbit that comes very close to Jupiter, and they\u2019re the most precious scientifically.\u201d<\/p>\n

One way scientists will investigate Jupiter with the Juno mission is by analysing the radio link between the probe and tracking antennas on Earth. The frequency of the radio transmission will register tiny changes in Juno\u2019s velocity caused by the subtle lumpiness of Jupiter\u2019s gravity, telling scientists about the planet\u2019s deep interior.<\/p>\n

Planetary scientists believe Jupiter harbours a solid core of rock and ice, but the hypothesis lacks proof. Juno may resolve that uncertainty.<\/p>\n

\u201cWe have no direct evidence that it even exists, let alone how big it is,\u201d said Levin, an astrophysicist who helps coordinate the Juno science team\u2019s relationship with NASA.<\/p>\n

\"Jupiter's
Jupiter\u2019s interior layers, including its potential dense inner core, are labeled in this illustration. Credit: NASA\/JPL-Caltech<\/figcaption><\/figure>\n

Juno\u2019s instruments will also attempt to track down the source of Jupiter\u2019s powerful magnetic field. Scientists currently think a global pool of liquid metallic hydrogen lies in the middle layer somewhere between Jupiter\u2019s core and atmosphere.<\/p>\n

\u201cThink about all three words. Liquid. Metallic. Hydrogen,\u201d Levin said, pausing for effect. \u201cHydrogen is the lightest element there is. If I filled a balloon here on Earth with it, it would float up into the sky. On Jupiter, the conditions are so intense, the pressure is so high from Jupiter\u2019s enormous gravity, that not only has that hydrogen gas been squeezed down into a liquid, it\u2019s squeezed so much the electrons are coming right off the atoms, so that it conducts electricity. It\u2019s a metal.\u201d<\/p>\n

The swirling motion of the hydrogen likely produces the magnetic field, which expands outward and is blown back by the solar wind like a comet\u2019s tail, according to Juno scientists. The magnetic field bubble, called a magnetosphere, is similar to one around Earth, but Jupiter\u2019s is so immense it would be the size of the full moon in the sky, if it was visible with the naked eye.<\/p>\n

\u201cThe interior of Jupiter is a tough problem for us,\u201d said Tobias Owen, a co-investigator on the Juno mission from the University of Hawaii. \u201cTo get deep inside, we have to use indirect methods. We can\u2019t go there. The temperature is too great. The pressure is too high \u2026 So what we have to do is to use the radiation thats coming to us from those lower depths to tell us whats going on down there, and this is where Juno comes in.\u201d<\/p>\n

Jupiter is a suitable case study for magnetospheric research because Earth\u2019s magnetic field comes from the planet\u2019s molten core, which is farther away from any scientific instrument on Earth\u2019s surface than Juno will be from Jupiter\u2019s supposed ocean of liquid metallic hydrogen.<\/p>\n

\u201cWhen looking at the magnetic field, we should be able to determine whether Jupiter has a solid inner core, and that has profound consequences for how Jupiter formed,\u201d says Jeremy Bloxham, a co-investigator on the Juno science team and professor at Harvard University.<\/p>\n

An infrared camera and ultraviolet spectrometer will take pictures of brilliant auroral displays on Jupiter\u2019s poles. At the same time Juno\u2019s particle detectors will help researchers trace the gas giant\u2019s magnetic field lines funneling electrons and ions into Jupiter\u2019s atmosphere, potentially uncovering the mechanism behind the northern and southern lights on the solar system\u2019s king planet.<\/p>\n

\"This
This view compares a lucky imaging view of Jupiter recently acquired from the European Southern Observatory\u2019s Very Large Telescope at infrared wavelengths with a very sharp amateur image in visible light from about the same time (right). The image acquired from a mid-infrared imager and spectrometer at the Very Large Telescope will aid Juno\u2019s observations of Jupiter\u2019s atmosphere. Credit: ESO\/L.N. Fletcher\/Damian Peach<\/figcaption><\/figure>\n

Known for its long-lived storms like the Great Red Spot, a sprawling anticyclonic storm first observed through telescopes in the 1600s, Jupiter\u2019s atmosphere is another subject of the Juno mission. The orbiter\u2019s microwave radiometer, similar to instruments aboard climate satellites looking down on Earth, will collect sounding measurements to peer below the red-orange tapestry of Jupiter\u2019s cloud tops.<\/p>\n

\n

\"20160616-Juno-July-Promo\"<\/p>\n

Find out more about the Juno mission in the July issue of Astronomy Now. Get your copy in the shops or order online. Or subscribe today and never miss an issue.<\/p>\n

\n

The radiometer is tuned to six wavelengths, detecting thermal radiation emitted from different layers of the atmosphere from the storm clouds and jet streams to as deep as 300 miles, or about 500 kilometers.<\/p>\n

\u201cWe see the Great Red Spot as a storm bigger than the entire Earth,\u201d Levin said. \u201cIt\u2019s been around for hundreds of years. We have an idea of what powers that. It\u2019s powered by the heat leaking out from inside Jupiter, but we want to know how deep does that go? How does that mechanism work? We see these belts and zones \u2014 jet streams \u2014 moving at hundreds of miles per hour around the planet in different directions. What drives that?\u201d<\/p>\n

One critical measurement sought by scientists is to quantify the amount of water contained in Jupiter\u2019s atmosphere. The water inside Jupiter is a significant clue about the solar system\u2019s earliest epoch more than 4.5 billion years ago, pointing scientists toward theories about where and how Jupiter formed.<\/p>\n

Dust and planetary building blocks coalesced to create Jupiter before any of the other planets formed, and the gas giant\u2019s gravitational influence overwhelmed the rest of the solar system outside of the sun. Scientists say knowing the conditions of the gas giant\u2019s genesis is essential to understanding how the other planets formed and evolved.<\/p>\n

\u201cWhat Jupiter evidently did as it formed was to scatter cold material that contained water ice and organic materials to the inner solar system, where it could be captured by the Earth and the other terrestrial planets,\u201d said Jonathan Lunine, a planetary scientist at Cornell University who works on Juno\u2019s science team.<\/p>\n

\"This
This montage of images captured by NASA\u2019s Pluto-bound New Horizons during a gravity assist flyby in February 2007 shows Jupiter and its volcanic moon Io. Credit: NASA\/JHUAPL\/SWRI<\/figcaption><\/figure>\n

The only data collected from inside Jupiter\u2019s atmosphere came from an entry probe deployed by the Galileo mission in 1995. It found the atmosphere to be hotter and drier than anticipated, causing some scientists to rethink their models on the births of planets.<\/p>\n

According to Levin, the consensus now is that the Galileo entry craft plunged into the atmosphere in an especially dry region. If current planetary formation theories are correct, Jupiter should contain more water than suggested by the Galileo probe.<\/p>\n

\u201cThe most important single number we\u2019re going to measure probably is the global abundance of water,\u201d Levin said.<\/p>\n

Juno will end its whirlwind tour of Jupiter in early 2018. That is when engineers predict radiation will degrade the spacecraft\u2019s electronics, prompting a command to dispatch the orbiter to be crushed inside Jupiter\u2019s atmosphere, a purposeful destruction to avoid a chance Juno could contaminate the planet\u2019s potentially habitable moons.<\/p>\n

\u201cSome people think we\u2019re crazy, but you\u2019re never going to learn these secrets unless you go in and try,\u201d Bolton said. \u201cAnd they\u2019re very closely-guarded secrets.\u201d<\/p>\n

Email the author.<\/i><\/b><\/p>\n

Follow Stephen Clark on Twitter: @StephenClark1.<\/strong><\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

A version of this story was originally published in Astronomy Now magazine. NASA\u2019s Juno spacecraft, seen here in an artist\u2019s illustration, will become the second mission to orbit the solar system\u2019s king planet. Credit: Lockheed Martin Whether you\u2019re a casual stargazer or armed with a toolkit of observing gadgets, chances are you have caught a […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[1183,1929,1606,472,1561,2612],"class_list":["post-15397","post","type-post","status-publish","format-standard","hentry","category-news","tag-jet-propulsion-laboratory","tag-juno","tag-jupiter","tag-lockheed-martin","tag-planetary-science","tag-swri"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/15397"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=15397"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/15397\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=15397"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=15397"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=15397"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}