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Special Guests:
This week’s guests will be the Universe Sandbox Developers Dan Dixon (Project Lead & Creator) and Jenn Seiler (Astrophysicist & Developer).
We’ve had an abundance of news stories for the past few months, and not enough time to get to them all. So we are now using a tool called Trello to submit and vote on stories we would like to see covered each week, and then Fraser will be selecting the stories from there. Here is the link to the Trello WSH page (http://bit.ly/WSHVote), which you can see without logging in. If you’d like to vote, just create a login and help us decide what to cover!
We record the Weekly Space Hangout every Friday at 12:00 pm Pacific / 3:00 pm Eastern. You can watch us live on Universe Today, or the Universe Today YouTube page.
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 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
“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.
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
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
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
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 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
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.
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
When we used to do the Virtual Star Party (and I really need to start those up again, they were super fun), I had the worst luck with Jupiter’s Great Red Spot. Whenever Jupiter was in the sky, the Great Red Spot always eluded us. Even though we should have had a 50/50 shot at seeing the massive storm on Jupiter, it was always hiding. Why so shy Jovian storm?
Jupiter’s Great Red Spot is an enormous swirling storm located on a band of clouds just south of the planet’s equator. It’s been there as long as people have been observing Jupiter with good enough telescopes to resolve it.
Astronomers somewhat disagree exactly when that was. The first person to mention a spot on Jupiter was Robert Hooke, who described it in 1664, but he placed it in the northern hemisphere. Oops.
A more reliable account comes from Giovanni Cassini, best known for his observations of Saturn. He observed a permanent spot in roughly the same location from 1665 to 1713.
Drawings by Cassini of what is presumably the Great Red Spot in 1665
The strange part is that astronomers lost track of it until 1830, when the modern Spot we know today was clearly evident. Were they two different spots? Did the GRS disappear and the flare up again? We’ll never know.
But really, isn’t that just splitting hairs? The thought that there’s been an enormous Jovian hurricane swirling away for hundreds of years is awesome and terrifying.
Here on Earth, we classify hurricanes as Category 1 when the wind speed crosses 119 km/h. A Category 4 hurricane can hit more than 250 km/h. That’s scary fast wind speed that can tear apart buildings. The Great Red Spot, on the other hand, can reach almost 650 km/h.
How big is this thing, anyway? Trust me, it’s big, but it used to be bigger. When astronomers first started keeping accurate measurements in the late 1800s, the Great Red Spot was about 40,000 kilometers wide and 14,000 kilometers tall.
Since that time, it’s been steadily shrinking. When the Voyager spacecraft flew past in the late 1970s, the spot had shrunk to 23,000 kilometers across. In 1995 Hubble measured it as 21,000 kilometers across, and then again in 2009, it was 18,000 kilometers across. About a year ago, Hubble did another measurement, and now it’s only 16,500 kilometers wide.
I say “only”, but keep in mind that the Earth measures 12,742 kilometers across. In other words, the Great Red Spot could still swallow up an Earth with room to spare.
The Juno spacecraft isn’t the first one to visit Jupiter. Galileo went there in the mid 90’s, and Voyager 1 snapped a nice picture of the clouds on its mission. Image: NASA
But this shrinking is continuing by about 930 kilometers per year. And as it shrinks, it’s changing from an oval to a more circular shape. At the same time, the color is changing too, lightening up – perhaps because the storm doesn’t dig too deeply into the lower atmospheric layers.
It’s possible that the Great Red Spot could completely disappear within our generation. And then every astronomer would fail to be able to see the Spot, just like me.
The Great Red Spot isn’t the only long lived storm on Jupiter, and this could be the reason why the Spot is disappearing.
If you look at images of Jupiter from Hubble, you can see other cyclonic storms; the biggest of which is known as Oval BA. It was first observed in 2000, after a few smaller storms collided and merged into a little red spot.
The formation of Oval BA. Credit: NASA/JPL/WFPC2
Over time, Oval BA has been getting larger and stronger, now it’s about the size of the Earth, and wind speeds have reached more than 600 km/h rivalling the Great Red Spot.
Because the bands on Jupiter alternate in directions, astronomers think that storms on the nearby bands are sapping the strength of the Great Red Spot. And perhaps they’re boosting Oval BA. There might be a time when the two spots are roughly the same size. And when the Great Red Spot finally disappears, Oval BA will be there to assume the mantle.
Since these storms can clearly grow and shrink over hundreds of years, I wonder what some of the strangest configurations of storms have ever been. I guess future robot-body Fraser will be the one to find out.
Good news! At the time that you’re watching this, NASA’s Juno spacecraft arrived at Jupiter on July 4, 2016. For the first time in more than a decade, we have a dedicated spacecraft at Jupiter, mapping, probing and analyzing the giant planet.
We should be getting more close up measurements and observations of the Great Red Spot and everything Jovian, so stay tuned, it’s going to be exciting.
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 ‘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
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
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
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
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
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
“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
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
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
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
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
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
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
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
After a nearly 5 year odyssey across the solar system, NASA’s solar powered Juno orbiter is all set to ignite its main engine late tonight and set off a powerful charge of do-or-die fireworks on America’s ‘Independence Day’ required to place the probe into orbit around Jupiter – the ‘King of the Planets.’
To achieve orbit, Juno must will perform a suspenseful maneuver known as ‘Jupiter Orbit Insertion’ or JOI tonight, Monday, July 4, upon which the entire mission and its fundamental science hinges. There are no second chances!
You can be part of all the excitement and tension building up to and during that moment, which is just hours away – and experience the ‘Joy of JOI’ by tuning into NASA TV tonight!
Watch the live webcast on NASA TV featuring the top scientists and NASA officials starting at 10:30 p.m. EDT (7:30 p.m. PST, 0230 GMT) – direct from NASA’s Jet Propulsion Laboratory: https://www.nasa.gov/nasatv
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
And for a breathtaking warm-up act, Juno’s on board public outreachJunoCam camera 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.
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.
NASA also released this new time-lapse JunoCam movie today:
Video caption: Juno’s Approach to Jupiter: After nearly five years traveling through space to its destination, NASA’s Juno spacecraft will arrive in orbit around Jupiter on July 4, 2016. This video shows a peek of what the spacecraft saw as it closed in on its destination. Credits: NASA/JPL-Caltech/MSSS
The spacecraft is approaching Jupiter over its north pole, affording an unprecedented perspective on the Jovian system – “which looks like a mini solar system,” said Juno Principal Investigator and chief scientist Scott Bolton, from the Southwest Research Institute (SwRI) in San Antonio, Tx, at today’s media briefing at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif.
“The deep interior of Jupiter is nearly unknown. That’s what we are trying to learn about.”
The 35-minute-long main engine burn is preprogrammed to start at 11:18 p.m. EDT (8:18 p.m. PST, 0318 GMT). It is scheduled to last until approximately 11:53 p.m. (8:53 p.m. PST, 0353 GMT).
Juno mission briefing July 4, 2016 at JPL by Jim Green, Scott Bolton, Rick Nybakken and Heidi Becker. Credit: Roland Keller/rkeusa.blogspot.com
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. Solar powered Juno is pointed away from the sun during the engine firing.
JOI is required to slow the spacecraft so it can be captured into the gas giant’s orbit as it closes in over the north pole.
Initially the spacecraft will enter a long, looping polar orbit lasting about 53 days. That highly elliptical orbit will quickly be trimmed to 14 days for the science orbits.
The orbits are designed to minimize contact with Jupiter’s extremely intense radiation belts. The 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.
Artist’s concept of NASA’s Juno spacecraft crossing the orbits of Jupiter’s four largest moons — Callisto, Gaynmede, Europa and Io — on its approach to Jupiter. Credits: NASA/JPL-Caltech
Juno is the fastest spacecraft ever to arrive at Jupiter and is moving at over 165,000 mph relative to Earth and 130,000 mph relative to Jupiter.
After a five-year and 2.8 Billion kilometer (1.7 Billion mile) outbound trek to the Jovian system and the largest planet in our solar system and an intervening Earth flyby speed boost, the moment of truth for Juno is now inexorably at hand.
Signals traveling at the speed of light take 48 minutes to reach Earth, said Rick Nybakken, Juno project manager from NASA’s Jet Propulsion Laboratory, at the media briefing.
So the main engine burn, which is fully automated, will already be over for some 13 minutes before the first indications of the outcome reach Earth via a series of Doppler shifts and tones. It is about 540 million miles (869 million kilometers) from Earth.
“By the time the burn is complete, we won’t even hear about it until 13 minutes later.”
“The engine burn will slow Juno by 542 meters/second (1,212 mph) and is fully automated as it approaches over Jupiter’s North Pole,” explained Nybakken.
“The long five year cruise enabled us to really learn about the spacecraft and how it operates.”
As it travels through space, the basketball court sized Juno is spinning like a windmill with its 3 giant solar arrays.
“Juno is also the farthest mission to rely on solar power. The solar panels are 60 square meters in size. And although they provide only 1/25th the power at Earth, they still provide over 500 watts of power at Jupiter.”
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
The protective cover that shields Juno’s main engine from micrometeorites and interstellar dust was opened on June 20.
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.
“Jupiter is the Rosetta Stone of our solar system,” says Bolton. “It is by far the oldest planet, contains more material than all the other planets, asteroids and comets combined and carries deep inside it the story of not only the solar system but of us. Juno is going there as our emissary — to interpret what Jupiter has to say.”
During the orbits, 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 $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.
Juno soars skyward to Jupiter on Aug. 5, 2011 from launch pad 41 at Cape Canaveral Air Force Station at 12:25 p.m. EDT. View from the VAB roof. Credit: Ken Kremer/kenkremer.com
Along the way Juno made a return trip to Earth on Oct. 9, 2013 for a flyby gravity assist speed boost that enabled the trek to Jupiter.
The flyby provided 70% of the velocity compared to the Atlas V launch, said Nybakken.
During the Earth flyby (EFB), the science team observed Earth using most of Juno’s nine science instruments since the slingshot also serves as an important dress rehearsal and key test of the spacecraft’s instruments, systems and flight operations teams.
What lessons were learned from the safe mode event and applied to JOI, I asked?
“We had the battery at 50% state of charge during the EFB and didn’t accurately predict the sag on the battery when we went into eclipse. We now have a validated high fidelity power model which would have predicted that sag and we would have increased the battery voltage,” Nybakken told Universe Today
“It will not happen at JOI as we don’t go into eclipse and are at 100% SOC. Plus the instruments are off which increases our power margins.”
For example the dazzling portrait of our Home Planet high over the South American coastline and the Atlantic Ocean.
For a hint of what’s to come, see our colorized Junocam mosaic of land, sea and swirling clouds, created by Ken Kremer and 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
The last NASA spacecraft to orbit Jupiter was Galileo in 1995. It explored the Jovian system until 2003.
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
Jupiter has an extremely powerful magnetic field. Ganymede has one, too, and is the only moon with one. Jupiter's envelops Ganymede's and their interactions are just part of the pair's complicated relationship. Image Credit: NASA Goddard Space Flight Center.
Jupiter is a huge planet, but its magnetosphere is mind-blowingly massive. It extends out to nearly 5 million kilometers (3 million miles) wide on average, 150 times wider than Jupiter itself and almost 15 times wider than the Sun, making it one of the largest structures in the Solar System.
“If you were to look up into the night sky and if we could see the outline of Jupiter’s magnetosphere, it would be about the size of the Moon in our sky,” said Jack Connerney, deputy principal investigator and head of the Juno mission magnetometer team. “It’s a very large feature in our Solar System, and it’s a pity we can’t see it.”
But the Juno spacecraft is about to change our understanding of Jupiter’s magnetosphere and allow scientists to “see” for the first time Jupiter’s magnetic field.
A magnetosphere is the area of space around a planet that is controlled by the planet’s magnetic field. The stronger the magnetic field, the larger the magnetosphere. It is estimated that Jupiter’s magnetic field is about 20,000 times stronger than Earth’s.
Jupiter has spectacular aurora, such as this view captured by the Hubble Space Telescope. Auroras are formed when charged particles in the space surrounding the planet are accelerated to high energies along the planet’s magnetic field. Credit: NASA, ESA, and J. Nichols (University of Leicester)
Magnetic fields are produced by what are known as dynamos – an electric current created from the convection motion of a planet’s interior. Earth’s magnetic field is generated by its circulating core of molten iron and nickel. But what creates Jupiter’s dynamo? Is it like Earth’s or could it be very different? Jupiter consists predominantly of hydrogen and helium, and it is currently unknown if there is a rocky core at the center of the planet.
“With Jupiter, we don’t know what material is producing the planet’s magnetic field,” said Jared Espley, Juno program scientist for NASA Headquarters, “What material is present and how deep down it lies is one of the questions Juno is designed to answer.”
Juno has a pair of magnetometers to basically look inside the planet. The magnetometers will allow scientists to map Jupiter’s magnetic field with high accuracy and observe variations in the field over time. The instruments will be able to show how the magnetic field is generated by dynamo action deep in the planet’s interior, providing the first look at what the magnetic field looks like from the surface of the dynamo where it is generated.
“The best way to think of a magnetometer is like a compass,” said Connerney. “Compasses record the direction of a magnetic field. But magnetometers expand on that capability and record both the direction and magnitude of the magnetic field.”
But Jupiter presents a lot of problems as far as being nice to instruments. Trapped within the magnetosphere are charged particles from the Sun that form intense radiation belts around the planet. These belts are similar to the Earth’s Van Allen belts, but are many millions of times stronger.
To help protect the spacecraft and instrument electronics, Juno has a radiation vault about the size of a car trunk made of titanium that limits the radiation exposure to Juno’s command and data handling box (the spacecraft’s brain), power and data distribution unit (its heart) and about 20 other electronic assemblies. But the instruments themselves need to be outside of the vault in order to make their observations. Workers place the special radiation vault for NASA’s Juno spacecraft onto the propulsion module. Image credit: NASA/JPL-Caltech/LMSS
The magnetometer sensors are on a boom attached to one of the solar arrays, placing them about 40 feet (12 meters) from the body of the spacecraft. This helps ensure that the rest of the spacecraft does not interfere with the magnetometer.
But there are other ways to help limit the amount of radiation exposure, at least in the first part of the mission.
Scientists designed a path that takes Juno around Jupiter’s poles so that the spacecraft spends the least amount of time possible in those blistering radiation belts around Jupiter’s equator. Engineers also used designs for electronics already approved for the Martian radiation environment, which is harsher than Earth’s, though not as harsh as Jupiter’s.
That elliptical orbit — between radiation belt and the planet — also puts the spacecraft very close to Jupiter, about 5,000 km above the cloud tops, enabling a close-up look at this amazing planet.
“This is our first opportunity to do very precise, high-accuracy mapping of the magnetic field of another planet,” Connerney said. “We are going to be able to explore the entire three-dimensional space around Jupiter, wrapping Jupiter in a dense net of magnetic field observations completely covering the sphere.”
By studying Jupiter’s magnetosphere, scientists will gain a better understanding about how Jupiter’s magnetic field is generated. They also hope to measure how fast Jupiter is spinning, determine whether the planet has a solid core, and learn more about Jupiter’s formation.
“It’s always incredible to be the first person in the world to see anything,” Connerney said, “and we stand to be the first to look down upon the dynamo and see it clearly for the first time.”
NASA's Deep Space Network is responsible for communicating with spacecraft. Pictured is the Goldstone facility in California, one of three facilities that make up the Network. Image: NASA/JPL
The much-anticipated arrival of NASA’s Juno spacecraft at Jupiter is almost here. Juno will answer many questions about Jupiter, but at the cost of a mission profile full of challenges. One of those challenges is communicating with Juno as it goes about its business in the extreme radiation environment around Jupiter. Communications with Juno rely on a network of radio dishes in strategic locations around the world, receivers cooled to almost absolute zero, and a team of dedicated people.
The task of communicating with Juno falls to NASA’s Deep Space Network (DSN), a system of three facilities around the world whose job it is to communicate with all of the spacecraft that venture outside Earth’s vicinity. That network is in the hands of Harris Corporation, experts in all sorts of communications technologies, who are contracted to run these crucial facilities.
The person responsible is Sonny Giroux, DSN Program Manager at Harris. In an interview with Universe Today, Sonny explained how the DSN works, and describes some of the challenges the Juno mission poses.
“The network itself consists of three primary communication facilities; one in Goldstone, California, out in the middle of the Mojave Desert. The other facility is in Madrid Spain, and the third is in Canberra Australia. These three facilities are separated by about 120 degrees, which means that any spacecraft that’s out there is capable of communicating with Earth at any point in time,” said Giroux.
Deep Space Network facilities are positioned 120 degrees apart to give total sky coverage. Image: NASA/JPL
“Each facility has several antennae, the largest of which is 70 m in diameter, about the size of a football field. These antennae can be aimed at any angle. Then there are smaller antennae at 34 m in size, and we have a number of those at each complex.”
According to Giroux, the dishes can work independently, or be arrayed together, depending on requirements. At the DSN website, you can see which antenna is communicating with which of NASA’s missions at any time.
At the Deep Space Network’s website, you can see which of the network’s dishes are communicating with which spacecraft. During Juno’s mission, you can expect to see its name beside many of the dishes. Image: NASA/JPL/DSN
Juno is a complex mission with a dynamic orbit, and Jupiter itself is an extreme radiation environment. Juno will have to weave its way through Jupiter’s radiation belts in its polar orbit. According to Giroux, this creates additional communication problems for the DSN.
“As Juno goes into its orbital insertion phase, the spacecraft will have to turn away from Earth. Our signal strength will drop dramatically,” Giroux said. “In order to capture the data that Juno is going to send, we’re going to array all of our antennae at Goldstone and Canberra together.”
Juno’s orbit around Jupiter will be highly elliptical as it contends with Jupiter’s powerful radiation belts. Image: NASA/JPL
This means that a total of 9 antennae will be arrayed in two groups to communicate with Juno. The 4 dishes at the Canberra, Australia site will be arrayed together, and the 5 dishes at the Goldstone, California site will be arrayed together.
This combined strength is crucial to the success of Juno during JOI (Juno Orbital Insertion.) Said Giroux, “We need to bring Juno’s signal strength up to the maximum amount that we can. We need to know what phases Juno is in as it executes its sequence.”
“We’ve never arrayed all of our antennae together like this. This is a first for Juno.”
This combined receiving power is a first for the DSN, and another first for the Juno mission. “We’ve never arrayed all of our antennae together like this,” said Giroux. “This is a first for Juno. We’ve done a couple together before for a spacecraft like Voyager, which is pretty far out there, but never all of them like this. In order to maximize our success with Juno, we’re arraying everything. It will be the first time in our history that we’ve had to array together all of our assets.”
Arraying multiple dishes together provides another benefit too, as Giroux told us. “The DSN is able to have two centres view the spacecraft at the same time. If one complex goes down for whatever reason, we would have the other one still available to communicate with the spacecraft.”
The most visible part of the DSN are the antennae themselves. But the electronics at the heart of the system are just as important. And they’re unique in the world, too.
“We cool them down to almost absolute zero to remove all of the noise out.”
“We have very specialized receivers that are built for the DSN. We cool them down to almost absolute zero to remove all of the noise out. That allows us to really focus on the signal that we’re looking for. These are unique to DSN,” said Giroux.
Juno itself has four different transmitters on-board. Some are able to transmit a lot of data, and some can transmit less. These will be active at different times, and form part of the challenge of communicating with Juno. Giroux told us, “Juno will be cycling through all four as it performs its insertion and comes back out again on the other side of the planet.”
“We just get the ones and zeroes…”
The DSN is a communications powerhouse, the most powerful tool ever devised for communicating in space. But it doesn’t handle the science. “DSN for the most part will receive whatever the spacecraft is sending to us. We just get the ones and zeroes and relay that data over to the mission. It’s the mission that breaks that down and turns it into science data.”
The three facilities that make up the DSN. Each is separated by 120 degrees. Image: NASA/JPL
Juno will be about 450 million miles away at Jupiter, which is about a 96 minute round trip for any signal. That great distance means that Juno’s signal strength is extremely weak. But it won’t be the weakest signal that the DSN contends with. A testament to the strength of the DSN is the fact that it’s still receiving transmissions from the Voyager probes, which are transmitting at miniscule power levels. According to Giroux, “Voyager is at a billionth of a billionth of a watt in terms of its signal strength.”
Juno is different than other missions like New Horizons and Voyager 1 and 2. Once Juno is done, it will plunge into Jupiter and be destroyed. So all of its data has to be captured quickly and efficiently. According to Giroux, that intensifies the DSN’s workload for the Juno mission.
“Juno is different. We’ve got to make sure to capture that data regularly.”
“Juno has a very defined mission length, with start and stop dates. It will de-orbit into Jupiter when it’s finished its science phase. That’s different than other missions like New Horizons where it has long periods where its able to download all of the data it’s captured. Juno is different. We’ve got to make sure to capture that data regularly. After JOI we’ll be in constant communication with Juno to make sure that’s happening.”
In preparation for the arrival of Juno, the ESO’s released stunning IR images of Jupiter, taken by the VLT. Credit: ESO
The next most important event in Juno’s mission is its orbital insertion around Jupiter, and Giroux and the team are waiting for that just like the rest of us are. “Juno’s big burn as it slows itself enough to be captured by Jupiter is a huge milestone that we’ll be watching for,” said Giroux.
The first signal that the DSN receives will be a simple three second beep. “Confirmation of the insertion will occur at about 9:40 p.m.,” said Giroux. That signal will have been sent about 45 minutes before that, but the enormous distance between Earth and Jupiter means a long delay in receiving it. But once we receive it, it will tell us that Juno has finished firing its engine for orbital insertion. Real science data, including images of Jupiter, will come later.
“We want to see a successful mission as much as anybody else.”
All of the data from the DSN flows through the nerve center at NASA’s Jet Propulsion Laboratory. When the signal arrives indicating that Juno has fired its engines successfully, Giroux and his team will be focussed on that facility, where news of Juno’s insertion will first be received. And they’ll be as excited as the rest of us to hear that signal.
“We want to see a successful mission as much as anybody else. Communicating with spacecraft is our business. We’ll be watching the same channels and websites that everybody else will be watching with bated breath,” said Giroux.
“Its great to be a part of the network. It’s pretty special.”
