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Forum:Satellites - Robotic Probes
Topic:NASA's Juno mission to explore Jupiter
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"Today, with the launch of the Juno spacecraft, NASA began a journey to yet another new frontier," NASA's Administrator Charles Bolden said. "The future of exploration includes cutting-edge science like this to help us better understand our solar system and an ever increasing array of challenging destinations."

After Juno's launch aboard an Atlas V rocket, mission controllers now await telemetry from the spacecraft indicating it has achieved its proper orientation, and that its massive solar arrays, the biggest on any NASA deep-space probe, have deployed and are generating power.

"We are on our way, and early indications show we are on our planned trajectory," said Jan Chodas, Juno project manager at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. "We will know more about Juno's status in a couple hours after its radios are energized and the signal is acquired by the Deep Space Network antennas at Canberra."


Credit: NASA/Bill Ingalls

Juno will cover the distance from Earth to the moon (about 250,000 miles or 402,236 kilometers) in less than one day's time. It will take another five years and 1,740 million miles (2,800 million kilometers) to complete the journey to Jupiter.

Juno will orbit the planet's poles 33 times and use its collection of eight science instruments to probe beneath the gas giant's obscuring cloud cover to learn more about its origins, structure, atmosphere, and magnetosphere, and look for a potential solid planetary core.

With four large moons and many smaller moons, Jupiter forms its own miniature solar system. Its composition resembles a star's, and if it had been about 80 times more massive, the planet could have become a star instead.


Credit: ULA/Pat Corkery

"Jupiter is the Rosetta Stone of our solar system," said Scott Bolton, Juno's principal investigator from the Southwest Research Institute in San Antonio. "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."

Juno's name comes from Greek and Roman mythology. The god Jupiter drew a veil of clouds around himself to hide his mischief, and his wife, the goddess Juno, was able to peer through the clouds and reveal Jupiter's true nature.

Robert Pearlman
Juno flying on its own to Jupiter

At 53 minutes and 14 seconds into its flight (1:18 p.m. EDT), the Juno spacecraft successfully separated from the Centaur upper stage and is now on its own on a path to Jupiter.

"Flight so far looks fantastic," NASA launch manager Omar Baez said, adding that Juno is in the right orbit to start its journey to Jupiter. "We're right on track for that, and everything looked good."

Juno has deployed its three tractor-trailer-size solar arrays. Each array is 29.5 feet long and 8.7 feet wide. There are 18,698 solar cells on the panels to generate approximately 400 watts of electricity once at Jupiter.

Robert Pearlman
Jupiter-bound Juno captures Earth and moon

On its way to the biggest planet in the solar system — Jupiter, NASA's Juno spacecraft took time to capture its home planet and its natural satellite — the moon.

"This is a remarkable sight people get to see all too rarely," said Scott Bolton, Juno principal investigator from the Southwest Research Institute in San Antonio. "This view of our planet shows how Earth looks from the outside, illustrating a special perspective of our role and place in the universe. We see a humbling yet beautiful view of ourselves."

The image was taken by the spacecraft's camera, JunoCam, on Aug. 26 when the spacecraft was about 6 million miles (9.66 million kilometers) away. The image was taken as part of the mission team's checkout of the Juno spacecraft. The team is conducting its initial detailed checks on the spacecraft's instruments and subsystems after its launch on Aug. 5.

Juno covered the distance from Earth to the moon (about 250,000 miles or 402,000 kilometers) in less than one day's time. It will take the spacecraft another five years and 1,740 million miles (2,800 million kilometers) to complete the journey to Jupiter.

The spacecraft will orbit the planet's poles 33 times and use its eight science instruments to probe beneath the gas giant's obscuring cloud cover to learn more about its origins, structure, atmosphere and magnetosphere, and look for a potential solid planetary core.

The solar-powered Juno spacecraft lifted off from Cape Canaveral Air Force Station in Florida at 9:25 a.m. PDT (12:25 p.m. EDT) on Aug. 5 to begin its five-year journey to Jupiter.

Robert Pearlman
Juno maneuvering for Earth flyby

Navigators and mission controllers for NASA's Juno mission to Jupiter have decided to reschedule the mission's second deep space maneuver for Sept. 14. The maneuver will set the stage for a gravity assist from a flyby of Earth on Oct. 9, 2013. Juno will arrive at Jupiter on July 4, 2016.

Juno's first deep space maneuver took place Aug. 30. The maneuver, as planned, changed the spacecraft's velocity by about 770 mph (344 meters a second) and lasted 29 minutes 39 seconds. Upon review of mission data following the burn, the team determined that although the first maneuver was completely successful, one of the propellant pressures within the spacecraft's propulsion system was higher than expected. The team has decided to take an extra 10 days to analyze this increase and consider mitigation options, placing the second deep space maneuver on Sept. 14. There will be no impact to the mission's timeline or science.

The two deep space maneuvers place Juno on course for its Earth flyby, which will occur as the spacecraft is completing one elliptical orbit around the sun. The Earth flyby will boost Juno's velocity by 16,330 mph (about 7.3 kilometers per second), placing the spacecraft on its final flight path for Jupiter. The closest approach to Earth on Oct. 9, 2013, will occur when Juno is at an altitude of about 310 miles (500 kilometers).

Robert PearlmanNASA release
NASA's Juno is Halfway to Jupiter

NASA's Juno spacecraft is halfway to Jupiter.

The Jovian-system-bound spacecraft reached the milestone Monday (Aug. 12) at 7:25 a.m. CDT (1225 GMT).

"Juno's odometer just clicked over to 9.464 astronomical units," said Juno Principal Investigator Scott Bolton, of the Southwest Research Institute in San Antonio. "The team is looking forward, preparing for the day we enter orbit around the most massive planet in our solar system."

For those astronomical-unitly challenged, an astronomical unit (AU) is a unit of measure used by space engineers and scientists when discussing the massive distances involved in the exploration of our solar system – and beyond. An AU is based on the distance between Earth and the sun and is 92,955,807.273 miles (149,597,870.7 kilometers) long. The 9.464 astronomical units Juno has already traveled (or still has left to go) is equivalent to 879,733,760 miles (or 1,415,794,248 kilometers). Juno was 34.46 million miles (55.46 million kilometers) from Earth when the milestone was reached.

The next milestone in the nearly five-year journey to Jupiter will occur this October, when the spacecraft flies past Earth in search of a little extra speed.

"On Oct. 9, Juno will come within 347 miles (559 kilometers) of Earth," said the mission's Project Manager Rick Nybakken of NASA's Jet Propulsion Laboratory in Pasadena, Calif. "The Earth flyby will give Juno a kick in the pants, boosting its velocity by 16,330 mph (about 7.3 kilometers per second). From there, it's next stop Jupiter."

Juno will arrive at Jupiter on July 4, 2016, at 9:29 p.m. CDT (0229 GMT July 5).

Juno was launched on Aug. 5, 2011. Once in orbit around Jupiter, the spacecraft will circle the planet 33 times, from pole to pole, and use its collection of eight science instruments to probe beneath the gas giant's obscuring cloud cover. Juno's science team will learn about Jupiter's origins, structure, atmosphere and magnetosphere, and look for a potential solid planetary core.

Juno's name comes from Greek and Roman mythology. The god Jupiter drew a veil of clouds around himself to hide his mischief, and his wife, the goddess Juno, was able to peer through the clouds and reveal Jupiter's true nature.

Robert PearlmanLockheed Martin release
Earth flyby to slingshot Juno to Jupiter

NASA's Juno spacecraft launched aboard an Atlas V rocket from Cape Canaveral Air Force Station, Fla., Aug. 5, 2011, beginning a five-year journey to Jupiter.

But it wasn't charted on a direct path.

Before it reaches its destination, Juno will greet the Earth one last time. The spacecraft will perform a flyby Oct. 9, passing within 347 miles of Earth.

The flyby will function as a gravity assist for Juno, with Earth's gravity accelerating the solar-powered spacecraft's velocity by 16,330 miles per hour. NASA launched Juno to an area just past Mars, then two main engine burns executed a year ago maneuvered it back around toward Earth.

The purpose of using a gravity assist to get Juno on its way to Jupiter is one of cost.

"A direct mission to Jupiter would have required about 50 percent more fuel than we loaded," said Tim Gasparrini, Juno program manager for Lockheed Martin Space Systems. "Had we not chosen to do the flyby, the mission would have required a bigger launch vehicle, a larger spacecraft and would have been more expensive."

Lockheed Martin's Juno team is playing an active and varied role in the mission and is preparing for the flyby.

"While flying Juno is a team effort, the core operations are in Denver," said Gasparrini. "We are responsible for systems engineering, subsystem performance and execution of the commanding that goes to the Juno spacecraft. During the flyby, the team will be monitoring the spacecraft because gravity is doing all the work."

NASA's Jet Propulsion Laboratory is providing the critical navigation for the mission and the flyby.

In the lead up to the flyby, Gasparrini's team has been active monitoring Juno.

"We've been doing final reviews on sequences necessary to conduct the flyby," said Jeff Lewis, spacecraft engineer and Lockheed Martin Space Systems operations lead for Juno. "Most of the commanding is folded into our 28-day background sequence, and most of the sequences started on Sept. 27."

For Lewis and others on the team, a big part of positioning Juno for a successful gravity assist is to ensure the spacecraft steers clear of other objects in its vicinity.

"The day of the Earth flyby, the team will be on hand to monitor things," said Lewis. "We have a couple of possible collision avoidance maneuvers to select from, looking at all the satellites around the Earth. We are passing inside the orbits of geostationary spacecraft."

Catching a velocity boost isn't the only value in the effort. The operation also will permit officials to test Juno's instruments and observe the spacecraft's flight handling.

"We'll exercise the science instruments, since Juno's instruments will be operating in a magnetospheric environment for the first time," said Lewis. "The Earth's magnetic field will allow a number of the instruments to be tested. We're also using the flyby of the moon as an opportunity to gauge how the spacecraft operates. Since Juno is a spinning spacecraft, we need to sense the right time to take data as the Moon, or Jupiter, passes through the instruments' fields of view."

On Aug. 12, Juno achieved a milestone by reaching the halfway point on its trek to Jupiter as it had traveled 9.46 astronomical units, equivalent to 879,733,760 miles, at that point. Demonstrating fortuitous timing, the spacecraft is scheduled to reach Jupiter July 4, 2016.

Juno's primary mission is to study Jupiter's atmosphere as a means of better understanding how the planet, and by extension, the solar system originated and evolved. Juno will employ its suite of scientific instruments to peer beneath the planet's dense cloud cover to study the existence of a solid planetary core, map Jupiter's magnetic field, measure water content in the atmosphere and study the planet's auroras.

The spacecraft will orbit Jupiter for about one year, or 33 orbits, operating at times as close as 3,100 miles above the planet's clouds.

According to Gasparrini, the Lockheed Martin Juno team is working collaboratively with other members of the overall Juno program team to ensure mission success. Other team members include NASA, the Jet Propulsion Laboratory, the Southwest Research Institute – including Scott Bolton, Juno's principal investigator – and a number of scientists throughout the world.

As the flyby approaches, Gasparrini and team are locked in and ready.

"The team is 100 percent focused on executing the Earth flyby successfully," said Gasparrini. "We've spent a lot of time looking at possible off-nominal conditions. In the presence of a fault, the spacecraft will stay healthy and will perform as planned."

Robert Pearlman
Juno enters 'safe mode' after Earth flyby

NASA's Juno probe detected an anomalous condition and went into safe mode Wednesday (Oct. 9) after slingshotting around Earth to gain momentum for the long trip to Jupiter, SPACE.com reported.

While Juno's mission managers are still attempting to discern what happened, they are hopeful that the problem won't threaten the $1.1 billion mission.

"We believe we are on track as planned to Jupiter," Juno project manager Rick Nybakken, with NASA's Jet Propulsion Laboratory, told the Associated Press, describing his level of concern as "moderate."

Data indicates the spacecraft obtained the predicted gravity boost from the flyby, Spaceflight Now reported, citing Scott Bolton, Juno's principal investigator from the Southwest Research Institute in San Antonio.

Bolton said Juno is designed to downlink data at a slower rate than normal during a safe mode, but telemetry from the spacecraft shows all its systems and instruments are fine.

Robert PearlmanSouthwest Research Institute release
Juno Spacecraft Resumes Full Flight Operations on Way to Jupiter

NASA's Juno spacecraft, which is on its way to Jupiter, resumed full flight operations Friday (Oct. 11). The spacecraft had entered safe mode during its flyby of Earth on Wednesday. The safe mode did not impact the spacecraft's trajectory one smidgeon. This flyby provided the necessary gravity boost to accurately slingshot the probe towards Jupiter, where it will arrive on July 4, 2016.

The spacecraft exited safe mode at 4:12 p.m. CDT (2112 GMT) on Friday.

The spacecraft is currently operating nominally and all systems are fully functional.

On Oct. 9, Juno past within 350 miles of the ocean just off the tip of South Africa at 2:21 p.m. CDT (1921 GMT). Soon after the closest approach, a signal was received by the European Space Agency's (ESA) 15-meter antenna just north of Perth, Australia, indicating the spacecraft initiated an automated fault-protection action called "safe mode."

Safe mode is a state that the spacecraft may enter if its on-board computer perceives conditions on the spacecraft are not as expected. Aboard Juno, the safe mode turned off instruments and a few non-critical spacecraft components, and pointed the spacecraft toward the Sun to ensure the solar arrays received power. The spacecraft acted as expected during the transition into and while in safe mode.

The Juno science team is continuing to analyze data acquired by the spacecraft's science instruments during the flyby. Most data and images were downlinked prior to the safe mode event.

Robert PearlmanNASA release
NASA's Juno Gives Starship-Like View of Earth Flyby

When NASA's Juno spacecraft flew past Earth on Oct. 9, 2013, it received a boost in speed of more than 8,800 mph (about 7.3 kilometer per second), which set it on course for a July 4, 2016, rendezvous with Jupiter, the largest planet in our solar system. One of Juno's sensors, a special kind of camera optimized to track faint stars, also had a unique view of the Earth-moon system. The result was an intriguing, low-resolution glimpse of what our world would look like to a visitor from afar.

"If Captain Kirk of the USS Enterprise said, 'Take us home, Scotty,' this is what the crew would see," said Scott Bolton, Juno principal investigator at the Southwest Research Institute, San Antonio. "In the movie, you ride aboard Juno as it approaches Earth and then soars off into the blackness of space. No previous view of our world has ever captured the heavenly waltz of Earth and moon."

The cameras that took the images for the movie are located near the pointed tip of one of the spacecraft's three solar-array arms. They are part of Juno's Magnetic Field Investigation (MAG) and are normally used to determine the orientation of the magnetic sensors. These cameras look away from the sunlit side of the solar array, so as the spacecraft approached, the system's four cameras pointed toward Earth. Earth and the moon came into view when Juno was about 600,000 miles (966,000 kilometers) away -- about three times the Earth-moon separation.

During the flyby, timing was everything. Juno was traveling about twice as fast as a typical satellite, and the spacecraft itself was spinning at 2 rpm. To assemble a movie that wouldn't make viewers dizzy, the star tracker had to capture a frame each time the camera was facing Earth at exactly the right instant. The frames were sent to Earth, where they were processed into video format.

"Everything we humans are and everything we do is represented in that view," said the star tracker's designer, John Jørgensen of the Danish Technical University, near Copenhagen.

Also during the flyby, Juno's Waves instrument, which is tasked with measuring radio and plasma waves in Jupiter's magnetosphere, recorded amateur radio signals. This was part of a public outreach effort involving ham radio operators from around the world. They were invited to say "HI" to Juno by coordinating radio transmissions that carried the same Morse-coded message. Operators from every continent, including Antarctica, participated.

"With the Earth flyby completed, Juno is now on course for arrival at Jupiter on July 4, 2016," said Rick Nybakken, Juno project manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

The Juno spacecraft was launched from Kennedy Space Center in Florida on August 5, 2011. Juno's launch vehicle was capable of giving the spacecraft only enough energy to reach the asteroid belt, at which point the sun's gravity pulled it back toward the inner solar system. Mission planners designed the swing by Earth as a gravity assist to increase the spacecraft's speed relative to the sun, so that it could reach Jupiter. (The spacecraft's speed relative to Earth before and after the flyby is unchanged.)

After Juno arrives and enters into orbit around Jupiter in 2016, the spacecraft will circle the planet 33 times, from pole to pole, and use its collection of science instruments to probe beneath the gas giant's obscuring cloud cover. Scientists will learn about Jupiter's origins, internal structure, atmosphere and magnetosphere.

Juno's name comes from Greek and Roman mythology. The god Jupiter drew a veil of clouds around himself to hide his mischief from his wife, but the goddess Juno used her special powers to peer through the clouds and reveal Jupiter's true nature.

See here for discussion of Juno's mission to the planet Jupiter.

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