A Proposal For Juno To Observe The Volcanoes Of Io

Io and volcanic plume. Credit: NASA/JPL-Caltech
To accomplish its science objectives, NASA’s Juno spacecraft orbits over Jupiter’s poles and passes repeatedly through hazardous radiation belts. Two Boston University researchers propose using Juno to probe the ever-changing flux of volcanic gases-turned-ions spewed by Io’s volcanoes. Credit: NASA/JPL-Caltech

Jupiter may be the largest planet in the Solar System with a diameter 11 times that of Earth, but it pales in comparison to its own magnetosphere. The planet’s magnetic domain extends sunward at least 3 million miles (5 million km) and on the back side all the way to Saturn for a total of 407 million miles or more than 400 times the size of the Sun.

Jupiter’s large magnetic field interacts with the solar wind to form an invisible magnetosphere. If we were able to see it, it would span at least several degrees of sky. It would show its greatest extent when viewing Jupiter from the side at quadrature, when the planet stands due south at sunrise or sunset.In the artist’s depiction, the planet would be located between the two “purple eyes” — too small to see at this scale. Credit: NASA.

If we had eyes adapted to see the Jovian magnetosphere at night, its teardrop-like shape would easily extend across several degrees of sky! No surprise then that Jove’s magnetic aura has been called one of the largest structures in the Solar System.

A 5-frame sequence taken by the New Horizons spacecraft in May 2007 shows a cloud of volcanic debris from Io’s Tvashtar volcano. The plume extends some 200 miles (330 km) above the moon’s surface. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Io, Jupiter’s innermost of the planet’s four large moons, orbits deep within this giant bubble. Despite its small size — about 200 miles smaller than our own Moon — it doesn’t lack in superlatives. With an estimated 400 volcanoes, many of them still active, Io is the most volcanically active body in the Solar System. In the moon’s low gravity, volcanoes spew sulfur, sulfur dioxide gas and fragments of basaltic rock up to 310 miles (500 km) into space in beautiful, umbrella-shaped plumes.

This schematic of Jupiter’s magnetic environments shows the planets looping magnetic field lines (similar to those generated by a simple bar magnet), Io and its plasma torus and flux tube. Credit: John Spencer / Wikipedia CC-BY-SA3.0 with labels by the author

Once aloft, electrons whipped around by Jupiter’s powerful magnetic field strike the neutral gases and ionize them (strips off their electrons). Ionized atoms and molecules (ions) are no longer neutral but possess a positive or negative electric charge. Astronomers refer to swarms of ionized atoms as plasma.

Jupiter rotates rapidly, spinning once every 9.8 hours, dragging the whole magnetosphere with it. As it spins past Io, those volcanic ions get caught up and dragged along for the ride, rotating around the planet in a ring called the Io plasma torus. You can picture it as a giant donut with Jupiter in the “hole” and the tasty, ~8,000-mile-thick ring centered on Io’s orbit.

That’s not all. Jupiter’s magnetic field also couples Io’s atmosphere to the planet’s polar regions, pumping Ionian ions through two “pipelines” to the magnetic poles and generating a powerful electric current known as the Io flux tube. Like firefighters on fire poles, the ions follow the planet’s magnetic field lines into the upper atmosphere, where they strike and excite atoms, spawning an ultraviolet-bright patch of aurora within the planet’s overall aurora. Astronomers call it Io’s magnetic footprint. The process works in reverse, too, spawning auroras in Io’s tenuous atmosphere.

The tilt of Juno’s orbit relative to Jupiter changes over the course of the mission, sending the spacecraft increasingly deeper into the planet’s intense radiation belts. Orbits are numbered from early in the mission to late. Credit: NASA/JPL-Caltech

Io is the main supplier of particles to Jupiter’s magnetosphere. Some of the same electrons stripped from sulfur and oxygen atoms during an earlier eruption return to strike atoms shot out by later blasts. Round and round they go in a great cycle of microscopic bombardment! The constant flow of high-speed, charged particles in Io’s vicinity make the region a lethal environment not only for humans but also for spacecraft electronics, the reason NASA’s Juno probe gets the heck outta there after each perijove or closest approach to Jupiter.

Io’s flux tube directs ions down Jupiter’s magnetic field lines to create magnetic footprints of enhanced aurora in Jupiter’s polar regions. An electric current of 5 million amps flows along Io’s flux tube.Credit: NASA/J.Clarke/HST

But there’s much to glean from those plasma streams.  Astronomy PhD student Phillip Phipps and assistant professor of astronomy Paul Withers of Boston University have hatched a plan to use the Juno spacecraft to probe Io’s plasma torus to indirectly study the timing and flow of material from Io’s volcanoes into Jupiter’s magnetosphere. In a paper published on Jan. 25, they propose using changes in the radio signal sent by Juno as it passes through different regions of the torus to measure how much stuff is there and how its density changes over time.

The technique is called a radio occultation. Radio waves are a form of light just like white light. And like white light, they get bent or refracted when passing through a medium like air (or plasma in the case of Io). Blue light is slowed more and experiences the most bending; red light is slowed less and refracted least, the reason red fringes a rainbow’s outer edge and blue its inner. In radio occultations, refraction results in changes in frequency caused by variations in the density of plasma in Io’s torus.

The best spacecraft for the attempt is one with a polar orbit around Jupiter, where it cuts a clean cross-section through different parts of the torus during each orbit. Guess what? With its polar orbit, Juno’s the probe for the job! Its main mission is to map Jupiter’s gravitational and magnetic fields, so an occultation experiment jives well with mission goals. Previous missions have netted just two radio occultations of the torus, but Juno could potentially slam dunk 24.

New Horizons took this photo of Io in infrared light. The Tvastar volcano is bright spot at top. At least 10 other volcanic hot spots dot the moon’s night side. Credit: NASA/JHUPL/SRI

Because the paper was intended to show that the method is a feasible one, it remains to be seen whether NASA will consider adding a little extra credit work to Juno’s homework. It seems a worthy and practical goal, one that will further enlighten our understanding of how volcanoes create aurorae in the bizarre electric and magnetic environment of the largest planet.

Juno Just Took One Of The Best Images Of Jupiter Ever

A portion of a new image taken by the JunoCam imager on NASA’s Juno spacecraft of Jupiter’s northern latitudes on Dec. 11, 2016. Credit: NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstaedt/John Rogers.

Wow! If you’ve ever wanted to know what it would be like to hang above Jupiter’s clouds, here you go. This absolutely stunning view of Jupiter’s northern latitudes shows incredible detail of gas giant’s swirling cloudtops. And it features, in the lower left in the image below, the storm on the gas planet known as NN-LRS-1, or more colloquially, the Little Red Spot.

The JunoCam imager on NASA’s Juno spacecraft snapped this shot of Jupiter’s northern latitudes on Dec. 11, 2016. Credit: NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstaedt/John Rogers.

Juno’s JunoCam, a visible light camera, is able to get never-before-seen images like this because it is doing something that no other mission to Jupiter has done.

“The spacecraft’s proximity to Jupiter is very unusual,” Rick Nybakken told me during an interview at JPL last year. Nybakken is Juno’s project manager. “Juno has an elliptical orbit that brings it just 3,107 miles (5,000 km) above the cloud tops. No other mission has been this close, and we’re right on top of Jupiter so to speak.”

Special instruments are studying Jupiter’s radiation belt and magnetosphere, its interior structure, and the turbulent atmosphere, as well as providing views of the planet with spectacular, close-up images.

And another great thing about this image is that it was processed by citizen scientists. Gerald Eichstaedt and John Rogers processed the image and drafted the caption, and this will be the norm for many of the JunoCam images, because it’s “the public’s camera.”

“I’m excited though for what we’re doing with the visible light camera,” said Juno Project Scientist Steve Levin, who I also interviewed at JPL. “We’re making JunoCam as much as much as we possibly can an instrument that belongs to the public. We’ll solicit the aid of the public in picking which images to take, and releasing the data in its rawest form, and allow people to go and make the images.”

Scientist Candy Hansen is leading this citizen science effort, and she uses the phrase, “science in a fishbowl,” meaning the JunoCam team is showing people what it is like to do science by allowing anyone to participate and see the data as it arrives from Juno.

Damian Peach reprocessed one of the latest images taken by Juno’s JunoCam during its 3rd close flyby of the planet on Dec. 11. The photo highlights two large ‘pearls’ or storms in Jupiter’s atmosphere. Credit: NASA/JPL-Caltech/SwRI/MSSS

You can find the raw images here, so go ahead and test out your image processing skills.

JunoCam is designed to capture remarkable pictures of Jupiter’s poles and cloud tops. Although its images will be helpful to the science team to help provide context for the spacecraft’s other instruments, it is not considered one of the mission’s science instruments. JunoCam was included on the spacecraft specifically for purposes of engaging and including the public.

The Little Red Spot is the third largest anticyclonic oval on the planet, which Earth-based observers have tracked for the last 23 years. An anticyclone is a weather phenomenon with large-scale circulation of winds around a central region of high atmospheric pressure. They rotate clockwise in the northern hemisphere, and counterclockwise in the southern hemisphere. The Little Red Spot shows very little color these days, just a pale brown smudge in the center. Back in 2006, the storm was stronger and the color changed darker and more red. Now, with the storm not quite as active, the color is very similar to the surroundings, making it difficult to see.

If you’d like to download a larger version of this processed image (need a new wallpaper?) you can find it on NASA’s website.

Juno Captures a Stunning Jovian ‘Pearl’

New Juno image of Jupiter taken on Dec. 11, 2016. Processed by Damian Peach
Damian Peach reprocessed one of the latest images taken by Juno's JunoCam during its 3rd close flyby of the planet on Dec. 11. The photo highlights two large 'pearls' or storms in Jupiter's atmosphere. Credit: NASA/JPL-Caltech/SwRI/MSSS
Astro-imager Damian Peach reprocessed one of the latest images taken by Juno’s JunoCam during its 3rd close flyby of the planet on Dec. 11. The photo highlights one of the large ‘pearls’ (right) that forms a string of  storms in Jupiter’s atmosphere. A smaller isolated storm is seen at left. Credit: NASA/JPL-Caltech/SwRI/MSSS

Jupiter looks beautiful in pearls! This image, taken by the JunoCam imager on NASA’s Juno spacecraft, highlights one of the eight massive storms that from a distance form a ‘string of pearls’ on Jupiter’s turbulent atmosphere. They’re counterclockwise rotating storms that appear as white ovals in the gas giant’s southern hemisphere. The larger pearl in the photo above is roughly half the size of Earth. Since 1986, these white ovals have varied in number from six to nine with eight currently visible.

Four more 'pearls' in the string of eight photographed on Dec. 10, 2016. They show up well in photos but require good seeing and at least and 8-inch telescope to see. Credit: Christopher Go
Four more ‘pearls’ photographed on Dec. 10, 2016 in the planet’s South Temperate Belt below the Great Red Spot. The moon Ganymede is at left. The show up well in photos but require good seeing and at least and 8-inch telescope to see visually. Credit: Christopher Go

The photos were taken during Sunday’s close flyby. At the time of closest approach — called perijove — Juno streaked about 2,580 miles (4,150 km) above the gas giant’s roiling, psychedelic cloud tops traveling about 129,000 mph or nearly 60 km per second relative to the planet. Seven of Juno’s eight science instruments collected data during the flyby. At the time the photos were taken, the spacecraft was about 15,300 miles (24,600 km) from the planet.

This is the original image sent by JunoCam on Dec. 11 and shows the 8th of the eight oval or 'pearls'in Jupiter's roiling atmosphere. Credit: NASA/JPL-Caltech/SwRI/MSSS
This is the original image sent by JunoCam on Dec. 11 and features the eighth in a string of large storms in the planet’s southern hemisphere. Credit: NASA/JPL-Caltech/SwRI/MSSS

JunoCam is a color, visible-light camera designed to capture remarkable pictures of Jupiter’s poles and cloud tops. As Juno’s eyes, it will provide a wide view, helping to provide context for the spacecraft’s other instruments. JunoCam was included on the spacecraft specifically for purposes of public engagement; although its images will be helpful to the science team, it is not considered one of the mission’s science instruments.

4-frame animation spans 24 Jovian days, or about 10 Earth days. The passage of time is accelerated by a factor of 600,000. Credit: NASA
4-frame animation spans 24 Jovian days, or about 10 Earth days. The passage of time is accelerated by a factor of 600,000. Some of the ovals are visible as well as a variety of jets – west to east and east to west. Credit: NASA

The crazy swirls of clouds we see in the photos are composed of ammonia ice crystals organized into a dozen or so bands parallel to the equator called belts (the darker ones) and zones. The border of each is bounded by a powerful wind flow called a jet, resembling Earth’s jet streams, which alternate direction from one band to the next.

Zones are colder and mark latitudes where material is upwelling from below. Ammonia ice is thought to give the zones their lighter color. Belts in contrast indicate sinking material; their color is a bit mysterious and may be due to the presence of hydrocarbons — molecules that are made from hydrogen, carbon, and oxygen as well as exotic sulfur and phosphorus compounds.

Use this guide to help you better understand Jupiter's arrangement of belts and zones, many of which are visible in amateur telescopes. Credit: NASA/JPL/Wikipedia
Use this guide to help you better understand Jupiter’s arrangement of belts and zones, many of which are visible in amateur telescopes. Credit: NASA/JPL/Wikipedia

The pearls or storms form in windy Jovian atmosphere and can last many decades. Some eventually dissipate while others merge to form even larger storms. Unlike hurricanes, which fall apart when they blow inland from the ocean, there’s no “land” on Jupiter, so storms that get started there just keep on going. The biggest, the Great Red Spot, has been hanging around causing trouble and delight (for telescopic observers) for at least 350 years.

Juno’s next perijove pass will happen on Feb. 2, 2017.

Juno Captures Jupiter’s Enthralling Poles From 2,500 Miles

JunoCam captured this image of Jupiter's north pole region from a distance of 78,000 km (48,000 miles) above the planet.
JunoCam captured this image of Jupiter's north pole region from a distance of 78,000 km (48,000 miles) above the planet.

Juno is sending data from Jupiter back to us, courtesy of the Deep Space Network, and the first images are meeting our hyped-up expectations. On August 27, the Juno spacecraft came within about 4,200 km. (2,500 miles) of Jupiter’s cloud tops. All of Juno’s instruments were active, and along with some high-quality images in visual and infrared, Juno also captured the sound that Jupiter produces.

Juno has captured the first images of Jupiter’s north pole. Beyond their interest as pure, unprecedented eye candy, the images of the pole reveal things never before seen. They show storm activity and weather patterns that are seen nowhere else in our solar system. Even on the other gas giants.

“…like nothing we have seen or imagined before.”

“First glimpse of Jupiter’s north pole, and it looks like nothing we have seen or imagined before,” said Scott Bolton, principal investigator of Juno from the Southwest Research Institute in San Antonio. “It’s bluer in color up there than other parts of the planet, and there are a lot of storms. There is no sign of the latitudinal bands or zone and belts that we are used to — this image is hardly recognizable as Jupiter. We’re seeing signs that the clouds have shadows, possibly indicating that the clouds are at a higher altitude than other features.”

The iconic storm bands of Jupiter are absent in this JunoCam image of Jupiter's northern polar region. Instead, the region is dominated by swirling storm patterns reminiscent of hurricanes here on Earth. Image: NASA/JPL-Caltech/SwRI/MSSS
The iconic storm bands of Jupiter are absent in this JunoCam image of Jupiter’s northern polar region. Instead, the region is dominated by swirling storm patterns reminiscent of hurricanes here on Earth. Image: NASA/JPL-Caltech/SwRI/MSSS

The visible light images of Jupiter’s north pole are very different from our usual perception of Jupiter. People have been looking at Jupiter for a long time, and the gas giant’s storm bands, and the Great Red Spot, are iconic. But the north polar region looks completely different, with whirling, rotating storms similar to hurricanes here on Earth.

The Junocam instrument is responsible for the visible light pictures of Jupiter that we all enjoy. But the Jovian Infrared Auroral Mapper (JIRAM) is showing us a side of Jupiter that the naked eye will never see.

The Juno Infrared Auroral Mapper (JIRAM) captured this infrared image of Jupiter's south pole. This part of Jupiter cannot be seen from Earth. Image: NASA/JPL-Caltech/SwRI/MSSS
The Juno Infrared Auroral Mapper (JIRAM) captured this infrared image of Jupiter’s south pole. This part of Jupiter cannot be seen from Earth. Image: NASA/JPL-Caltech/SwRI/MSSS

“JIRAM is getting under Jupiter’s skin, giving us our first infrared close-ups of the planet,” said Alberto Adriani, JIRAM co-investigator from Istituto di Astrofisica e Planetologia Spaziali, Rome. “These first infrared views of Jupiter’s north and south poles are revealing warm and hot spots that have never been seen before. And while we knew that the first-ever infrared views of Jupiter’s south pole could reveal the planet’s southern aurora, we were amazed to see it for the first time.”

“No other instruments, both from Earth or space, have been able to see the southern aurora.”

Even when we’re prepared to be amazed by what Juno and other spacecraft show us, we are still amazed. It’s impossible to see Jupiter’s south pole from Earth, so these are everybody’s first glimpses of it.

“No other instruments, both from Earth or space, have been able to see the southern aurora,” said Adriani. “Now, with JIRAM, we see that it appears to be very bright and well-structured. The high level of detail in the images will tell us more about the aurora’s morphology and dynamics.”

Beyond the juicy images of Jupiter are some sound recordings. It’s been known since about the 1950’s that Jupiter is a noisy planet. Now Juno’s Radio/Plasma Wave Experiment (WAVE) has captured a recording of that sound.

“Jupiter is talking to us in a way only gas-giant worlds can,” said Bill Kurth, co-investigator for the Waves instrument from the University of Iowa, Iowa City. “Waves detected the signature emissions of the energetic particles that generate the massive auroras which encircle Jupiter’s north pole. These emissions are the strongest in the solar system. Now we are going to try to figure out where the electrons come from that are generating them.”

Oddly enough, that’s pretty much exactly what I expected Jupiter to sound like. Like something from an early sci-fi film.

There’s much more to come from Juno. These images and recordings of Jupiter are just the result of Juno’s first orbit. There are over 30 more orbits to come, as Juno examines the gas giant as it orbits beneath it.

JUNO Transmits First Up-Close Look Soarin’ over Jupiter

Jupiter's north polar region is coming into view as NASA's Juno spacecraft approaches the giant planet. This view of Jupiter was taken on August 27, when Juno was 437,000 miles (703,000 kilometers) away. Credits: NASA/JPL-Caltech/SwRI/MSSS
Jupiter's north polar region is coming into view as NASA's Juno spacecraft approaches the giant planet. This view of Jupiter was taken on August 27, when Juno was 437,000 miles (703,000 kilometers) away.   Credits: NASA/JPL-Caltech/SwRI/MSSS
Jupiter’s north polar region is coming into view as NASA’s Juno spacecraft approaches the giant planet. This view of Jupiter was taken on August 27, when Juno was 437,000 miles (703,000 kilometers) away. Credits: NASA/JPL-Caltech/SwRI/MSSS

NASA’s JUNO spacecraft successfully swooped over the Jovian cloud tops today, Saturday, Aug. 27, gathering its first up close images and science observations of the ‘King of the Planets’ since braking into orbit on America’s Independence Day.

Saturdays’ close encounter with Jupiter soaring over its north pole was the first of 36 planned orbital flyby’s by Juno during the scheduled 20 month long prime mission.

“Soarin’ over #Jupiter. My 1st up-close look of the gas-giant world was a success!” the probe tweeted today post-flyby.

NASA released Juno’s first up-close image taken by the JunoCam visible light camera just hours later – as seen above.

Juno was speeding at some 130,000 mph (208,000 kilometers per hour) during the time of Saturday’s closest approach at 9:44 a.m. EDT (6:44 a.m. PDT 13:44 UTC) over the north polar region.

It passed merely 2,600 miles (4,200 kilometers) above the turbulent clouds of the biggest planet in our solar system during its initial 53.5 day polar elliptical capture orbit.

And apparently everything proceeded as the science and engineering team leading the mission to the gas giant had planned.

“Early post-flyby telemetry indicates that everything worked as planned and Juno is firing on all cylinders,” said Rick Nybakken, Juno project manager at NASA’s Jet Propulsion Laboratory in Pasadena, California, in a statement.

This dual view of Jupiter was taken on August 23, when NASA's Juno spacecraft was 2.8 million miles (4.4 million kilometers) from the gas giant planet on the inbound leg of its initial 53.5-day capture orbit. Credit: NASA/JPL-Caltech/SwRI/MSSS
This dual view of Jupiter was taken on August 23, when NASA’s Juno spacecraft was 2.8 million miles (4.4 million kilometers) from the gas giant planet on the inbound leg of its initial 53.5-day capture orbit. Credit: NASA/JPL-Caltech/SwRI/MSSS

Indeed Saturday’s encounter will count as the closest of the entire prime mission. It also marks the first time that the entire suite of nine state-of-the-art science instruments had been turned on to gather the totally unique observations of Jupiter’s interior and exterior environment.

“We are getting some intriguing early data returns as we speak,” said Scott Bolton, principal investigator of Juno from the Southwest Research Institute in San Antonio, in a statement.

“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.”

Additional up-close high resolution imagery of the Jovian atmosphere, swirling cloud tops and north and south poles snapped by JunoCam will be released in the coming weeks, perhaps as soon as next week.

“We are in an orbit nobody has ever been in before, and these images give us a whole new perspective on this gas-giant world,” said Bolton.

“It will take days for all the science data collected during the flyby to be downlinked and even more to begin to comprehend what Juno and Jupiter are trying to tell us.”

The prime mission is scheduled to end in February of 2018 with a suicide plunge into the Jovian atmosphere to prevent any possible contamination with Jupiter’s potentially habitable moons such as Europa and Ganymede.

“No other spacecraft has ever orbited Jupiter this closely, or over the poles in this fashion,” said Steve Levin, Juno project scientist from NASA’s Jet Propulsion Laboratory in Pasadena, California. “This is our first opportunity and there are bound to be surprises. We need to take our time to make sure our conclusions are correct.”

The team did release an approach image taken by JunoCam on Aug. 23 when the spacecraft was 2.8 million miles (4.4 million kilometers) from the gas giant planet on the inbound leg of its initial 53.5-day capture orbit.

One additional long period orbit is planned. The main engine will fire again in October to reduce the orbit to the 14 day science orbit.

Animation of Juno 14-day orbits starting in late 2016.  Credits: NASA/JPL-Caltech
Animation of Juno 14-day orbits starting in late 2016. Credits: NASA/JPL-Caltech

The solar powered probe will collect unparalleled new data that will unveil the hidden inner secrets of Jupiter’s origin and evolution as it peers “beneath the obscuring cloud cover of Jupiter and study its auroras to learn more about the planet’s origins, structure, atmosphere and magnetosphere.”

The $1.1 Billion Juno was launched on Aug. 5, 2011 from Cape Canaveral Air Force Station, Florida atop the most powerful version of the Atlas V rocket augmented by 5 solid rocket boosters and built by United Launch Alliance (ULA). That same Atlas V 551 version recently launched MUOS-5 for the US Navy on June 24.

The Juno spacecraft was built by prime contractor Lockheed Martin in Denver.

Illustration of NASA's Juno spacecraft firing its main engine to slow down and go into orbit around Jupiter. Lockheed Martin built the Juno spacecraft for NASA's Jet Propulsion Laboratory.  Credit: NASA/Lockheed Martin
Illustration of NASA’s Juno spacecraft firing its main engine to slow down and go into orbit around Jupiter. Lockheed Martin built the Juno spacecraft for NASA’s Jet Propulsion Laboratory. Credit: NASA/Lockheed Martin

The last NASA spacecraft to orbit Jupiter was Galileo in 1995. It explored the Jovian system until 2003.

In the final weeks of the approach before Jupiter Orbit Insertion (JOI), JunoCam captured dramatic views of Jupiter and all four of the Galilean Moons moons — Io, Europa, Ganymede and Callisto.

At the post JOI briefing at JPL on July 5, these were combined into a spectacular JunoCam time-lapse movie released by Bolton and NASA.

Watch and be mesmerized -“for humanity, our first real glimpse of celestial harmonic motion” says Bolton.

Video caption: NASA’s Juno spacecraft captured a unique time-lapse movie of the Galilean satellites in motion about Jupiter. The movie begins on June 12th with Juno 10 million miles from Jupiter, and ends on June 29th, 3 million miles distant. The innermost moon is volcanic Io; next in line is the ice-crusted ocean world Europa, followed by massive Ganymede, and finally, heavily cratered Callisto. Galileo observed these moons to change position with respect to Jupiter over the course of a few nights. From this observation he realized that the moons were orbiting mighty Jupiter, a truth that forever changed humanity’s understanding of our place in the cosmos. Earth was not the center of the Universe. For the first time in history, we look upon these moons as they orbit Jupiter and share in Galileo’s revelation. This is the motion of nature’s harmony. Credits: NASA/JPL-Caltech/MSSS

Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.

Ken Kremer

United Launch Alliance Atlas V liftoff with NASA’s Juno to Jupiter orbiter on Aug. 5, 2011 from Cape Canaveral Air Force Station, Florida. Credit: Ken Kremer/kenkremer.com
United Launch Alliance Atlas V liftoff with NASA’s Juno to Jupiter orbiter on Aug. 5, 2011 from Cape Canaveral Air Force Station, Florida. Credit: Ken Kremer/kenkremer.com

What Can We Expect From Juno’s Return To Jupiter?

Illustration of NASA's Juno spacecraft firing its main engine to slow down and go into orbit around Jupiter. Lockheed Martin built the Juno spacecraft for NASA's Jet Propulsion Laboratory. Credit: NASA/Lockheed Martin

The Juno spacecraft made history on July 4th, 2016, when it became the second spacecraft in history to achieve orbit around Jupiter for the sake of a long-term mission. Following in the footsteps of the Galileo mission, the probe will spend the next 20 months gathering data on Jupiter’s atmosphere, clouds, interior and gravitational and magnetic fields, before purposefully crashing into the planet.

And on Saturday, August 27th, Juno will be making history once again. According to NASA, at precisely 12:51 UTC (5:51 a.m. PDT, 8:51 a.m. EDT) the spacecraft will be passing closer to the cloud tops of Jupiter than at any point in its main mission. And while the probe is expected to make 35 more close flybys of the gas giant before its mission ends in February of 2018, this particular one is expected to be especially revealing.

For one, it will be the first time that the probe has all of its scientific instruments online and surveying Jupiter’s atmosphere as it swings past. And during the flyby, the probe will be passing Jupiter’s cloud tops at a distance of 4,200 kilometers (2,500 miles) – closer than it will ever get again – while traveling at a speed of 208,000 km/hour (130,000 mph).

This annotated color view of Jupiter and its four largest moons -- Io, Europa, Ganymede and Callisto -- was taken by the JunoCam camera on NASA's Juno spacecraft on June 21, 2016, at a distance of 6.8 million miles (10.9 million kilometers) from Jupiter. Image credit: NASA/JPL-Caltech/MSSS
This annotated color view of Jupiter and its four largest moons — Io, Europa, Ganymede and Callisto — was taken by the JunoCam camera on NASA’s Juno spacecraft on June 21, 2016, at a distance of 6.8 million miles (10.9 million kilometers) from Jupiter. Image credit: NASA/JPL-Caltech/MSSS

This will not only be the closest approach to Jupiter made by any probe, but it will pass over Jupiter’s poles, which will give Juno the opportunity to get a look at some never-before-seen things. These will include infrared and microwave readings taken by Juno’s suite of eight instruments, but also some choice photographs.

Yes, in addition to its sensor package, Juno‘s visible light imager (aka. JunoCam) will also be active and taking some close-up pictures of the atmosphere and poles. While the scientific information is expected to keep NASA scientists occupied for some time to come, the JunoCam images are expected to be released later next week.

According to NASA, these images will be the highest resolution photos of the Jovian atmosphere ever taken, not to mention the first glimpse of Jupiter’s north and south poles ever. As Scott Bolton, principal investigator of Juno from the Southwest Research Institute in San Antonio, said in a NASA press release:

“This is the first time we will be close to Jupiter since we entered orbit on July 4. 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.”

NASA's Juno spacecraft launched on August 6, 2011 and should arrive at Jupiter on July 4, 2016. Credit: NASA / JPL
NASA’s Juno spacecraft launched on August 6, 2011 and should arrive at Jupiter on July 4, 2016. Credit: NASA / JPL

Ever since the Juno spacecraft launched on Aug. 5th, 2011, from Cape Canaveral, Florida, scientists and astronomers have been waiting for the day when it would start sending back information on the Solar System’s greatest planet. By examining the atmosphere, interior, and magnetic environment of the gas giant, scientists hope to be able to answer burning questions about the history of the planet’s formation.

For example, Jupiter’s interior structure and composition, as well as what drives its magnetic field, are still the subject of debate. In addition, there are some unanswered questions about when and where the planet formed. While it may have formed in its current orbit, some evidence suggests that it could have formed farther from the sun before migrating inward. All of these questions, it is hoped, are things the Juno mission will answer.

In so doing, scientists hope to be able to shed some additional light on the history of the Solar System as well. Like the other gas giants, it was assembled during the early phases, before our Sun had the chance to absorb or blow away the light gases in the huge cloud from which both were born. As such, Jupiter’s composition could tell us much about the early Solar System.

And this Saturday, the probe will be gathering what could prove to be the most crucial information its mission will produce. And of course, if all goes well, it will be taking the most detailed pictures of the Jovian giant to date! Godspeed, little Juno. You be careful out there!

Further Reading: NASA

Juno Transmits 1st Orbital Imagery after Swooping Arrival Over Jovian Cloud Tops and Powering Up

This color view from NASA's Juno spacecraft is made from some of the first images taken by JunoCam after the spacecraft entered orbit around Jupiter on July 4, 2016. Credits: NASA/JPL-Caltech/SwRI/MSSS
This color view from NASA's Juno spacecraft is made from some of the first images taken by JunoCam after the spacecraft entered orbit around Jupiter on July 4, 2016.  Credits: NASA/JPL-Caltech/SwRI/MSSS
This color view from NASA’s Juno spacecraft is made from some of the first images taken by JunoCam after the spacecraft entered orbit around Jupiter on July 4, 2016. Credits: NASA/JPL-Caltech/SwRI/MSSS

NASA’s newly arrived Jovian orbiter Juno has transmitted its first imagery since reaching orbit last week on July 4 after swooping over Jupiter’s cloud tops and powering back up its package of state-of-the-art science instruments for unprecedented research into determining the origin of our solar systems biggest planet.

The breathtaking image clearly shows the well known banded cloud tops in Jupiter’s atmosphere as well as the famous Great Red Spot and three of the humongous planet’s four largest moons — Io, Europa and Ganymede.

The ‘Galilean’ moons are annotated from left to right in the lead image.

Juno’s visible-light camera named JunoCam was turned on six days after Juno fired its main engine to slow down and be captured into orbit around Jupiter – the ‘King of the Planets’ following a nearly five year long interplanetary voyage from Earth.

The image was taken when Juno was 2.7 million miles (4.3 million kilometers) distant from Jupiter on July 10, at 10:30 a.m. PDT (1:30 p.m. EDT, 5:30 UTC), and traveling on the outbound leg of its initial 53.5-day capture orbit.

Juno came within only about 3000 miles of the cloud tops and passed through Jupiter’s extremely intense and hazardous radiation belts during orbital arrival over the north pole.

Illustration of NASA's Juno spacecraft firing its main engine to slow down and go into orbit around Jupiter. Lockheed Martin built the Juno spacecraft for NASA's Jet Propulsion Laboratory.  Credit: NASA/Lockheed Martin
Illustration of NASA’s Juno spacecraft firing its main engine to slow down and go into orbit around Jupiter. Lockheed Martin built the Juno spacecraft for NASA’s Jet Propulsion Laboratory. Credit: NASA/Lockheed Martin

The newly released JunoCam image is visible proof that Juno survived the do-or-die orbital fireworks on America’s Independence Day that placed the baskeball-court sized probe into orbit around Jupiter – and is in excellent health to carry out its groundbreaking mission to elucidate Jupiter’s ‘Genesis.’

“This scene from JunoCam indicates it survived its first pass through Jupiter’s extreme radiation environment without any degradation and is ready to take on Jupiter,” said Scott Bolton, principal investigator from the Southwest Research Institute in San Antonio, in a statement.

“We can’t wait to see the first view of Jupiter’s poles.”

Within two days of the nerve wracking and fully automated 35-minute-long Jupiter Orbital Insertion (JOI) maneuver, the Juno engineering team begun powering up five of the probes science instruments on July 6.

Animation of Juno 14-day orbits starting in late 2016.  Credits: NASA/JPL-Caltech
Animation of Juno 14-day orbits starting in late 2016. Credits: NASA/JPL-Caltech

All nonessential instruments and systems had been powered down in the final days of Juno’s approach to Jupiter to ensure the maximum chances for success of the critical JOI engine firing.

“We had to turn all our beautiful instruments off to help ensure a successful Jupiter orbit insertion on July 4,” said Bolton.

“But next time around we will have our eyes and ears open. You can expect us to release some information about our findings around September 1.”

Juno resumed high data rate communications with Earth on July 5, the day after achieving orbit.

We can expect to see more JunoCam images taken during this first orbital path around the massive planet.

But the first high resolution images are still weeks away and will not be available until late August on the inbound leg when the spacecraft returns and swoops barely above the clouds.

“JunoCam will continue to take images as we go around in this first orbit,” said Candy Hansen, Juno co-investigator from the Planetary Science Institute, Tucson, Arizona, in a statement.

“The first high-resolution images of the planet will be taken on August 27 when Juno makes its next close pass to Jupiter.”

All of JunoCams images will be released to the public.

During a 20 month long science mission – entailing 37 orbits lasting 14 days each – the probe will plunge to within about 2,600 miles (4,100 kilometers) of the turbulent cloud tops.

It will collect unparalleled new data that will unveil the hidden inner secrets of Jupiter’s origin and evolution as it peers “beneath the obscuring cloud cover of Jupiter and study its auroras to learn more about the planet’s origins, structure, atmosphere and magnetosphere.”

The solar powered Juno spacecraft approached Jupiter over its north pole, affording an unprecedented perspective on the Jovian system – “which looks like a mini solar system” – as it flew through the giant planets intense radiation belts in ‘autopilot’ mode.

Juno is the first solar powered probe to explore Jupiter or any outer planet.

In the final weeks of the approach JunoCam captured dramatic views of Jupiter and all four of the Galilean Moons moons — Io, Europa, Ganymede and Callisto.

At the post JOI briefing on July 5, these were combined into a spectacular JunoCam time-lapse movie released by Bolton and NASA.

Watch and be mesmerized -“for humanity, our first real glimpse of celestial harmonic motion” says Bolton.

Video caption: NASA’s Juno spacecraft captured a unique time-lapse movie of the Galilean satellites in motion about Jupiter. The movie begins on June 12th with Juno 10 million miles from Jupiter, and ends on June 29th, 3 million miles distant. The innermost moon is volcanic Io; next in line is the ice-crusted ocean world Europa, followed by massive Ganymede, and finally, heavily cratered Callisto. Galileo observed these moons to change position with respect to Jupiter over the course of a few nights. From this observation he realized that the moons were orbiting mighty Jupiter, a truth that forever changed humanity’s understanding of our place in the cosmos. Earth was not the center of the Universe. For the first time in history, we look upon these moons as they orbit Jupiter and share in Galileo’s revelation. This is the motion of nature’s harmony. Credits: NASA/JPL-Caltech/MSSS

The $1.1 Billion Juno was launched on Aug. 5, 2011 from Cape Canaveral, Florida atop the most powerful version of the Atlas V rocket augmented by 5 solid rocket boosters and built by United Launch Alliance (ULA). That same Atlas V 551 version just launched MUOS-5 for the US Navy on June 24.

The Juno spacecraft was built by prime contractor Lockheed Martin in Denver.

The mission will end in February 2018 with an intentional death dive into the atmosphere to prevent any possibility of a collision with Europa, one of Jupiter’s moons that is a potential abode for life.

The last NASA spacecraft to orbit Jupiter was Galileo in 1995. It explored the Jovian system until 2003.

From Earth’s perspective, Jupiter was in conjunction with Earth’s Moon shortly after JOI during the first week in July.

Personally its thrilling to realize that an emissary from Earth is once again orbiting Jupiter after a 13 year long hiatus as seen in the authors image below – coincidentally taken the same day as JunoCam’s first image from orbit.

Juno, Jupiter and the Moon as seen from I-95 over Dunn, NC on July 10, 2016. Credit: Ken Kremer/kenkremer.com
Juno, Jupiter and the Moon as seen from I-95 over Dunn, NC on July 10, 2016. Credit: Ken Kremer/kenkremer.com

Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.

Ken Kremer

………….

Learn more about Juno at Jupiter, SpaceX CRS-9 rocket launch, ISS, ULA Atlas and Delta rockets, Orbital ATK Cygnus, Boeing, Space Taxis, Mars rovers, Orion, SLS, Antares, NASA missions and more at Ken’s upcoming outreach events:

July 15-18: “SpaceX launches to ISS on CRS-9, Juno at Jupiter, ULA Delta 4 Heavy spy satellite, SLS, Orion, Commercial crew, Curiosity explores Mars, Pluto and more,” Kennedy Space Center Quality Inn, Titusville, FL, evenings

NASA's Juno probe captured the image data for this composite picture during its Earth flyby on Oct. 9 over Argentina,  South America and the southern Atlantic Ocean. Raw imagery was reconstructed and aligned by Ken Kremer and Marco Di Lorenzo, and false-color blue has been added to the view taken by a near-infrared filter that is typically used to detect methane. Credit: NASA/JPL/SwRI/MSSS/Ken Kremer/Marco Di Lorenzo
NASA’s Juno probe captured the image data for this composite picture during its Earth flyby on Oct. 9 over Argentina, South America and the southern Atlantic Ocean. Raw imagery was reconstructed and aligned by Ken Kremer and Marco Di Lorenzo, and false-color blue has been added to the view taken by a near-infrared filter that is typically used to detect methane. Credit: NASA/JPL/SwRI/MSSS/Ken Kremer/Marco Di Lorenzo

Jovians Distressed At Strange, Tiny & Silent Creatures Aboard Spacecraft

The three Lego figures inside: Galileo, Juno and Jupiter. Source: NASA

Given its historic importance – being just the second spacecraft to conduct a long-term mission to Jupiter – NASA was sure to outfit the Juno probe with some high-end memorabilia. These include the Galileo commemorative plaque*, which shows Galileo’s face and the words he wrote when he first observed Jupiter’s four largest moons in 1610 (known today as the Galilean Moons).

In addition, three commemorative figures (each measuring 4 cm high) were created especially for the mission. Created by Lego, these figurines depict the Roman god Jupiter, his wife Juno, and the astronomer Galileo Galilei – each holding an identifying object. Constructed from aluminum so they could withstand the trip and the radiation of the gas giant, these figures arrived with the probe around Jupiter on Monday, July 4th.

Much like the Juno spacecraft that is ferrying them, these figurines have spent the past 5 years in space and traversing the 869 million kilometers that lie between Earth from Jupiter. As part of Lego’s “Build Your Future” campaign,  the trio are part of an educational outreach program to inspire kids around the world to learn about science and technology.

A key part of this effort is the Building Challenge launched by Lego to raise awareness about space exploration. For this challenge, participants are asked to build their vision of the future of space exploration using Lego bricks, take pictures of their creation, and then upload them to the Lego website’s “Mission to Space” gallery. The winning creations will be featured on LEGO.com and the Gallery homepage.

NASA's Juno spacecraft launched on August 6, 2011 and should arrive at Jupiter on July 4, 2016. Credit: NASA / JPL
NASA’s Juno spacecraft launched on August 6, 2011 and should arrive at Jupiter on July 4, 2016. Credit: NASA / JPL

In addition, Lego’s website has new content that encourages children to learn more about the Solar System. As they state on the webpage:

“Have you ever wondered what it would be like if you could visit other planets and travel through space? Well, here’s your chance to go on a mission to Space through a partnership between NASA and LEGO Group! Pack your space lunch, and get ready to fly the International Space Station, pass the Moon, to Mars and Jupiter! Learn fun facts about our solar system, play quizzes, and get a taste of life as an astronaut and space pioneer! Round off the trip by entering an out-of-this-world building challenge.”

True to their mythological roots, the figurine of Jupiter (the Roman equivalent of Zeus) is holding a lightning bolt. Juno, his wife, is holding a magnifying glass, which represents her ability to see through the clouds that Jupiter surrounded himself with. And Galileo, the famed astronomer who was the first to view Jupiter’s moons, holds his famed telescope and an orb representing Jupiter.

These three figurines are the closest thing the Juno spacecraft has to a crew. During the next two years, they will be with the probe as it orbits Jupiter a total of 37 times, conducting surveys of Jupiter’s atmosphere, interior, magnetosphere, and gravitational field. When the mission is over, they will deorbit with the probe, crashing into Jupiter’s atmosphere to prevent any contamination of Jupiter’s moons.

Three LEGO figurines representing the Roman god Jupiter, his wife Juno and Galileo Galilei are shown here aboard the Juno spacecraft. Credits: NASA/JPL-Caltech/KSC
Three LEGO figurines representing the Roman god Jupiter, his wife Juno and Galileo Galilei are shown here aboard the Juno spacecraft. Credits: NASA/JPL-Caltech/KSC

Over the course of the past three days, numerous memes have popped up across the internet, claiming that: “When Galileo first spotted Jupiter’s largest moons, he named them after Jove’s (Zeus’) mistresses. Now, a probe named after his wife will arrive in the system, thus fulfilling a joke astronomers have been setting up for the past 400 years!” – I’m paraphrasing, of course!

Nevertheless, the observation is an apt one. And to make this witty statement complete, all those figures who had a hand in lending Jupiter the cultural significant it has (be they historical or mythological) will be represented as Juno tries to unveil Jupiter’s mysteries. Sure, those likenesses are just 4 cm in height, and they are built out of aluminum instead of marble, but it’s the thought that counts!

*The Galileo commemorative plague contains script written in Italian by Galileo’s own hand. It reads:

“On the 11th it was in this formation, and the star closest to Jupiter was half the size than the other and very close to the other so that during the previous nights all of the three observed stars looked of the same dimension and among them equally afar; so that it is evident that around Jupiter there are three moving stars invisible till this time to everyone.”

And be sure to enjoy this video of NASA’s Juno team celebrating the probe’s arrival at Jupiter:

Further Reading: NASA June, Lego

The Moon Occults Jupiter This Weekend

The Moon occults Jupiter
The Moon occults Jupiter on July 15th, 2012. Image credit and copyright: Ziad el Zaatari.

So, are you catching sight of the waxing crescent Moon returning this week to the early PM sky? The start of lunation 1157 gives folks observing Ramadan here in Morocco a reason to celebrate, as it marks the end of dawn-to-dusk fasting. Follow that Moon, as it’s about to meet up with the king of the planets this weekend.

On July 9th, the 5-day old waxing crescent Moon will pass Jupiter. You can see ’em both Saturday night, high in the western sky at dusk. For a very few observers in the southern Indian Ocean and Antarctica, the Moon will actually occult (pass in front of) Jupiter, centered on 10:11 Universal Time (UT). The Moon will be 32% illuminated crescent during the pass, and Jupiter will present a disk 34” across, just over a month past quadrature on June 4th with a current elongation of 60 degrees east of the Sun. Jupiter just passed opposition for 2016 on March 8th, and is now headed towards solar conjunction on the far side of the Sun on September 26th.

The occultation footprint for the July 9th event. Image credit: Occult 4.2 software.
The occultation footprint for the July 9th event. Image credit: Occult 4.2 software.

2016 Planetary Occultations

This is the first of four occultations of Jupiter by the Moon in 2016; the next occur over subsequent lunations on August 6th, September 2nd and 30th before the relative motions of the Moon and Jupiter carry them apart, not to meet again until October 31st, 2019. And though most observers will miss this weekend’s occultation, we’ll all get a good view of the pairing worldwide. Unfortunately, the view gets successively worse (though more central) for the next few lunations, as the occultations of Jupiter by the Moon occur close to the Sun.

Looking west on the evening of July 9th. Image credit: Stellarium.
Looking west on the evening of July 9th. Image credit: Stellarium.

Here’s another reason to celebrate and show off Jupiter at this weekend’s star party: NASA’s Juno spacecraft has just entered orbit around the gas giant world. This is only the second time a mission has orbited Jupiter (the first was Galileo) though lots have performed brief flybys, using the enormous pull of the planet for a gravitational boost en route to elsewhere. Juno is currently the only spacecraft in operation around Jove, and will conduct 36 looping science orbits around the planet before meeting its fiery end in February 2018.

A montage of daytime planets. Image credit and copyright: Shahrin Ahmad (@shahgazer).
A montage of daytime planets (and one Moon and one star). Image credit and copyright: Shahrin Ahmad (@shahgazer).

Yay, humans. Here’s another feat of visual athletics you can attempt this weekend: can you spy Jupiter near the waxing crescent Moon… in the daytime? It’s not that tough, if you know exactly where to look. Deep blue skies for maxim contrast are key, and don’t be afraid to cheat a bit and use binoculars or a wide-field DSLR shot to tease bashful Jupiter out of the daytime sky. Your best bet might be to start hunting for Jupiter 30 minutes prior to local sunset. Hey, if the Sun is still above the local horizon, it still counts! We’ve actually managed to nab Jupiter and Venus before sundown at public star parties on occasion, kicking things off a bit early.

Hunting for Jupiter in the daytime on July 9th. Image credit: Starry Night
Hunting for Jupiter in the daytime on July 9th. Image credit: Starry Night

Now for the ‘wow’ factor. The Moon is 3,474 kilometers across, and on average, 400,000 kilometers or 1.25 light seconds distant. Jupiter, at 140,000 kilometers across, is currently 5.9 Astronomical Units (AU) or 880 million kilometers away, 2,200 times more distant at 49 light minutes away. You could fit Jupiter and all of the other planets in the solar system – excluding Saturn’s rings — between the Earth and the Moon… not that you’d want such mayhem, of course. Hey; then, for the very first time in the history of human astronomy, Jupiter could occult our puny Moon…

Occultations are abruptly swift affairs in a glacially slow universe. The leading edge of the Moon moves about 30” a minute, taking 17 seconds to cover the disk of Jove. Follow Jupiter this summer, as it’ll pass just 4′ from Venus in the dusk sky on August 27th.

More to come on that soon. Here’s a final thought: has anyone ever tried to observe a radio occultation of Jupiter by the Moon? It’s certainly possible, as Jupiter is a prominent amateur radio source, crackling in the sky. And hey, the daytime sky thing wouldn’t be an issue…

We’d be thrilled to hear that, against all odds, someone on a remote windswept island or on a ship in the distant Indian Ocean actually managed to catch this weekend’s occultation!

Welcome to Jupiter – NASA’s Juno Achieves Orbit around ‘King of the Planets’

Illustration of NASA's Juno spacecraft firing its main engine to slow down and go into orbit around Jupiter. Lockheed Martin built the Juno spacecraft for NASA's Jet Propulsion Laboratory. Credit: NASA/Lockheed Martin
Illustration of NASA's Juno spacecraft firing its main engine to slow down and go into orbit around Jupiter. Lockheed Martin built the Juno spacecraft for NASA's Jet Propulsion Laboratory.
Illustration of NASA’s Juno spacecraft firing its main engine to slow down and go into orbit around Jupiter. Lockheed Martin built the Juno spacecraft for NASA’s Jet Propulsion Laboratory. Credit: NASA/Lockheed Martin

Welcome to Jupiter! NASA’s Juno spacecraft is orbiting Jupiter at this moment!

“NASA did it again!” pronounced an elated Scott Bolton, investigator of Juno from Southwest Research Institute in San Antonio, to loud cheers and applause from the overflow crowd of mission scientists and media gathered at the post orbit media briefing at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif.

After a nearly five year journey covering 1.7-billion-miles (2.8-billion-kilometers) across our solar system, NASA’s basketball court-sized Juno orbiter achieved orbit around Jupiter, the ‘King of the Planets’ late Monday night, July 4, in a gift to all Americans on our 240th Independence Day and a gift to science to elucidate our origins.

“We are in orbit and now the fun begins, the science,” said Bolton at the briefing. “We just did the hardest thing NASA’s ever done! That’s my claim. I am so happy … and proud of this team.”

And the science is all about peering far beneath the well known banded cloud tops for the first time to investigate Jupiter’s deep interior with a suite of nine instruments, and discover the mysteries of its genesis and evolution and the implications for how we came to be.

“The deep interior of Jupiter is nearly unknown. That’s what we are trying to learn about. The origin of us.”

Solar powered Juno successfully entered a polar elliptical orbit around Jupiter after completing a must-do 35-minute-long firing of the main engine known as Jupiter Orbital Insertion or JOI.

The spacecraft approached Jupiter over its north pole, affording an unprecedented perspective on the Jovian system – “which looks like a mini solar system” – as it flew through the giant planets intense radiation belts in ‘autopilot’ mode.

“The mission team did great. The spacecraft did great. We are looking great. It’s a great day,” Bolton gushes.

Engineers tracking the telemetry received confirmation that the JOI burn was completed as planned at 8:53 p.m. PDT (11:53 p.m. EDT) Monday, July 4.

Juno is only the second probe from Earth to orbit Jupiter and the first solar powered probe to the outer planets. The gas giant is two and a half times more massive than all of the other planets combined.

“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 in a statement.

“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.”

Artists concept NASA's Juno spacecraft firing its main engine to slow down and go into orbit around Jupiter on July 4, 2016 nearly five years after launch.   Credit: NASA
Artists concept NASA’s Juno spacecraft firing its main engine to slow down and go into orbit around Jupiter on July 4, 2016 nearly five years after launch. Credit: NASA

The do-or-die burn of Juno’s 645-Newton Leros-1b main engine started at 8:18 p.m. PDT (11:18 p.m. EDT), which had the effect of 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. There were no second chances.

All of the science instruments were turned off on June 30 to keep the focus on the nail-biting insertion maneuver and preserve battery power, said Bolton.

“So tonight through tones Juno sang to us. And it was a song of perfection. After a 1.7 billion mile journey we hit tour burn targets within one second,” Rick Nybakken, Juno project manager from JPL, gleefully reported at the briefing.

“That’s how good our team is! And that’s how well our Juno spacecraft performed tonight.”

To accomplish the burn, the spacecraft first had to adjust it’s attitude to point the engine in the required direction to slow the spacecraft and then simultaneously also had the effect that the life giving solar panels were pointing away from the sun. It the only time during the entire mission at Jupiter that the solar panels were in darkness and not producing energy.

The spacecraft’s rotation rate was also spun up from 2 to 5 revolutions per minute (RPM) to help stabilize it during JOI. Juno is spin stabilized to maintain pointing.

After the burn was complete, Juno was spun down and adjusted to point to the sun before it ran out of battery power.

We have to get the blood flowing through Juno’s veins, Bolton emphasized.

It is equipped with 18,698 individual solar cells over 60 square meters of surface on the solar arrays to provide energy. Juno is spinning like a windmill through space with its 3 giant solar arrays. It is about 540 million miles (869 million kilometers) from Earth.

Juno mission briefing on  July 5, 2016 at JPL after the successful JOI orbit insertion on July 4.  Credit: Roland Keller/rkeusa.blogspot.com
Juno mission briefing on July 5, 2016 at JPL after the successful JOI orbit insertion on July 4. Credit: Roland Keller/rkeusa.blogspot.com

Signals traveling at the speed of light take 48 minutes to reach Earth, said Nybakken.

So the main engine burn, which was fully automated, was already over for some 13 minutes before the first indications of the outcome reach Earth via a series of Doppler signals and tones.

“Tonight, 540 million miles away, Juno performed a precisely choreographed dance at blazing speeds with the largest, most intense planet in our solar system,” said Guy Beutelschies, director of Interplanetary Missions at Lockheed Martin Space Systems.

“Since launch, Juno has operated exceptionally well, and the flawless orbit insertion is a testament to everyone working on Juno and their focus on getting this amazing spacecraft to its destination. NASA now has a science laboratory orbiting Jupiter.”

“The spacecraft is now pointed back at the sun and the antenna back at Earth. The spacecraft performed well and did everything it needed to do,” he reported at the briefing.

“We are looking forward to getting all that science data to Scott and the team.”

“Juno is also the farthest mission to rely on solar power. And although they provide only 1/25th the power at Earth, they still provide over 500 watts of power at Jupiter,” said Nybakken.

Initially the spacecraft enters a long, looping polar orbit lasting about 53 days. That highly elliptical orbit will be trimmed to 14 days for the regular science orbits.

The orbits are designed to minimize contact with Jupiter’s extremely intense radiation belts. The nine science instruments are shielded inside a ½ thick vault built of Titanium to protect them from the utterly deadly radiation of some 20,000,000 rads.

During a 20 month long science mission – entailing 37 orbits lasting 14 days each – the probe will plunge to within about 3000 miles of the turbulent cloud tops and collect unprecedented new data that will unveil the hidden inner secrets of Jupiter’s origin and evolution.

But the length and number of the science orbits has changed since the mission was launched almost 5 years ago in 2011.

Originally Juno was planned to last about one year with an orbital profile involving 33 orbits of 11 days each.

I asked the team to explain the details of how and why the change from 11 to 14 days orbits and increasing the total number of orbits to 37 from 33, especially in light of the extremely harsh radiation hazards?

“The original plan of 33 orbits of 11 days was an example but there were other periods that would work,” Bolton told Universe Today.

“What we really cared about was dropping down over the poles and capturing each longitude, and laying a map or net around Jupiter.”

“Also, during the Earth flyby we went into safe mode. And as we looked at that it was a hiccup by the spacecraft but it actually behaved as it should have.”

“So we said well if that happened at Jupiter we would like to be able to recover and not lose an orbit. So we started to look at the timeline of how long it took to recover, and did we want to add a couple of days to the orbit for conservatism – to ensure the science mission.”

“So it made sense to add 3 days. It didn’t change the science and it made the probability of success even greater. So that was the basis of the change.”

“We also evaluated the radiation. And it wasn’t much different. Juno is designed to take data at a very low risk. The radiation slowly accumulates at the start. As you get to the later part of the mission, it gets a faster and faster accumulation.”

“So we still retained that conservatism as well and the overall radiation dose was pretty much the same,” Bolton explained.

“The radiation we accumulate is not just the more time you spend the more radiation,” Steve Levin, Juno Project Scientist at JPL, told Universe Today.

“Each time we come in close to the planet we get a dose of radiation. Then the spacecraft is out far from Jupiter and is relatively free from that radiation until we come in close again.”

“So just changing from 11 to 14 day orbits does not mean we get more radiation because you are there longer.”

“It’s really the number of times we come in close to Jupiter that determines how much radiation we are getting.”

Juno is the fastest spacecraft ever to arrive at Jupiter and was moving at over 165,000 mph relative to Earth and 130,000 mph relative to Jupiter at the moment of JOI.

Juno’s principal goal is to understand the origin and evolution of Jupiter.

“With its suite of nine science instruments, Juno will investigate the existence of a solid planetary core, map Jupiter’s intense magnetic field, measure the amount of water and ammonia in the deep atmosphere, and observe the planet’s auroras. The mission also will let us take a giant step forward in our understanding of how giant planets form and the role these titans played in putting together the rest of the solar system. As our primary example of a giant planet, Jupiter also can provide critical knowledge for understanding the planetary systems being discovered around other stars,” according to a NASA description.

The $1.1 Billion Juno was launched on Aug. 5, 2011 from Cape Canaveral, Florida atop the most powerful version of the Atlas V rocket augmented by 5 solid rocket boosters and built by United Launch Alliance (ULA). That same Atlas V 551 version just launched MUOS-5 for the US Navy on June 24.

The Juno spacecraft was built by prime contractor Lockheed Martin in Denver.

United Launch Alliance Atlas V liftoff with NASA’s Juno to Jupiter orbiter on Aug. 5, 2011 from Cape Canaveral Air Force Station, Florida. Credit: Ken Kremer/kenkremer.com
United Launch Alliance Atlas V liftoff with NASA’s Juno to Jupiter orbiter on Aug. 5, 2011 from Cape Canaveral Air Force Station, Florida. Credit: Ken Kremer/kenkremer.com

The last NASA spacecraft to orbit Jupiter was Galileo in 1995. It explored the Jovian system until 2003.

Bolton also released new views of Jupiter taken by JunoCam – the on board public outreach camera that snapped a final gorgeous view of the Jovian system showing Jupiter and its four largest moons, dancing around the largest planet in our solar system.

The newly released color image was taken on June 29, 2016, at a distance of 3.3 million miles (5.3 million kilometers) from Jupiter – just before the probe went into autopilot mode.

This is the final view taken by the JunoCam instrument on NASA's Juno spacecraft before Juno's instruments were powered down in preparation for orbit insertion. Juno obtained this color view on June 29, 2016, at a distance of 3.3 million miles (5.3 million kilometers) from Jupiter.  See timelapse movie below.  Credits: NASA/JPL-Caltech/MSSS
This is the final view taken by the JunoCam instrument on NASA’s Juno spacecraft before Juno’s instruments were powered down in preparation for orbit insertion. Juno obtained this color view on June 29, 2016, at a distance of 3.3 million miles (5.3 million kilometers) from Jupiter. See timelapse movie below. Credits: NASA/JPL-Caltech/MSSS

It shows a dramatic view of the clouds bands of Jupiter, dominating a spectacular scene that includes the giant planet’s four largest moons — Io, Europa, Ganymede and Callisto.

Scott Bolton and NASA also released this spectacular new time-lapse JunoCam movie at today’s briefing showing Juno’s approach to Jupiter and the Galilean Moons.

Watch and be mesmerized -“for humanity, our first real glimpse of celestial harmonic motion” says Bolton.

Video caption: NASA’s Juno spacecraft captured a unique time-lapse movie of the Galilean satellites in motion about Jupiter. The movie begins on June 12th with Juno 10 million miles from Jupiter, and ends on June 29th, 3 million miles distant. The innermost moon is volcanic Io; next in line is the ice-crusted ocean world Europa, followed by massive Ganymede, and finally, heavily cratered Callisto. Galileo observed these moons change position with respect to Jupiter over the course of a few nights. From this observation he realized that the moons were orbiting mighty Jupiter, a truth that forever changed humanity’s understanding of our place in the cosmos. Earth was not the center of the Universe. For the first time in history, we look upon these moons as they orbit Jupiter and share in Galileo’s revelation. This is the motion of nature’s harmony. Credits: NASA/JPL-Caltech/MSSS

Along the 5 year journey to Jupiter, Juno made a return trip to Earth on Oct. 9, 2013 for a flyby gravity assist speed boost that enabled the trek to the Jovian system.

During the Earth flyby (EFB), the science team observed Earth using most of Juno’s nine science instruments including, JunoCam, since the slingshot also served as an important dress rehearsal and key test of the spacecraft’s instruments, systems and flight operations teams.

The JunoCam images will be made publicly available to see and process.

During the Earth flyby, Junocam snapped some striking images of Earth as it sped over Argentina, South America and the South Atlantic Ocean and came within 347 miles (560 kilometers) of the surface.

For example a dazzling portrait of our Home Planet high over the South American coastline and the Atlantic Ocean gives a hint of what’s to come from Jupiter’s cloud tops. See our colorized Junocam mosaic of land, sea and swirling clouds, created by Ken Kremer and Marco Di Lorenzo

This colorized composite shows more than half of Earth’s disk over the coast of Argentina and the South Atlantic Ocean as the Juno probe slingshotted by on Oct. 9, 2013 for a gravity assisted acceleration to Jupiter. The mosaic was assembled from raw images taken by the Junocam imager. Credit: NASA/JPL/SwRI/MSSS/Ken Kremer/Marco Di Lorenzo
This colorized composite shows more than half of Earth’s disk over the coast of Argentina and the South Atlantic Ocean as the Juno probe slingshotted by on Oct. 9, 2013 for a gravity assisted acceleration to Jupiter. The mosaic was assembled from raw images taken by the Junocam imager. Credit: NASA/JPL/SwRI/MSSS/Ken Kremer/Marco Di Lorenzo

Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.

Ken Kremer

Rick Nybakken, Juno project manager at JPL illustrates how Juno will enter orbit around Jupiter during Juno mission briefing on July 4, 2016 at JPL. Credit: Roland Keller/rkeusa.blogspot.com
Rick Nybakken, Juno project manager at JPL illustrates how Juno will enter orbit around Jupiter during Juno mission briefing on July 4, 2016 at JPL. Credit: Roland Keller/rkeusa.blogspot.com