Juno probe

It's going to be riveting to watch. Jupiter, at the moment, is 365 million miles away but can get in it's orbit to around 601 million miles away.

Size comparison




Jupiter

​

A belt of asteroids (fragments of rock and iron) between Mars and Jupiter separate the four inner planets from the five outer planets.

Jupiter, the largest planet in our solar system, was named for the most important Roman god because of its size. About 1,300 Earths would fit into it. Viewed through a large telescope, Jupiter is stunningly colorful—it is a disk covered with bands of blue, brown, pink, red, orange, and yellow. Its most distinguishing feature is “the Great Red Spot,” an intense windstorm larger in size than Earth, which has continued for centuries without any signs of dying down.

• Size: 11 times the diameter of Earth
• Diameter: 88,736 miles (142,800 km)
• Surface: A hot ball of gas and liquid
• Atmosphere: Whirling clouds of colored dust, hydrogen, helium, methane, water, and ammonia. The Great Red Spot is an intense windstorm larger than Earth.
• Temperature: –234°F (–148°C) average
• Rotation of its axis: 9 hours and 55 minutes
• Rotation around the Sun: 12 Earth years
• Your weight: If you weigh 100 pounds on Earth, you would weigh 265 pounds on Jupiter.
• Distance from Earth: At its closest, 370 million miles (591 million km)
• Mean Distance from Sun: 483.88 million miles (778.3 million km)
• Satellites: 63
• Rings: 4

 

I often watch it with the telescope and it never fails to make my jaw drop. While it's easy to see the 4 Moons, Ganymede, Europa, Io, and Callisto, I'd love to see the other 59 Moons Jupiter has. This year has not been brilliant for Planet watching due to the weather and the fact that Mars is quite low on the horizon although it is in it's closest position for two years. But Jupiter you can see shining brightly with the naked eye and with binoculars and it's amazing to think when you gaze up to look at it that we've got a probe out there. It's a great time for Astronomy and Science.

 

As an example of my viewing, martin, the trees would come up level with Antares and finish just around Spica.

 

After a 5-year-long journey, NASA's Juno probe, an emissary to the largest planet in the solar system, has arrived at its destination and slipped into orbit around Jupiter.


An artist's conception of Juno performing a 35-minute-long engine firing to enter orbit around Jupiter.
NASA / JPL

"Joy" at the Jet Propulsion Laboratory's mission control center today is spelled JOI — for Jupiter Orbital Insertion.

July 4th fireworks erupted in the outer solar system overnight, as theJuno probe fired its main engine and entered a polar orbit around Jupiter at 11:53 p.m. EDT (Earth receive time), which was 3:53 Universal Time (UT) on July 5th. Juno carried out a scheduled 35-minute-long burn that slowed its velocity by 542 meters per second (1,212 mph), enough to become a captured satellite of Jupiter with an initial 53.5-day orbital period. Arriving at 58 km per second with respect to the planet, Juno also performed the fastest orbital insertion to date.

"Independence Day always is something to celebrate, but today we can add to America's birthday another reason to cheer — Juno is at Jupiter," notes NASA administrator Charlie Bolden in a post-arrival press release. "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."

Unfortunately, Juno won't return any eye-candy images during its arrival, as all science instruments were turned off during the crucial engine burn. Juno resumed full transmissions to Earth 58 minutes after the the thruster lit up, indicating all is well with the spacecraft. At 5.8 astronomical units (a.u.) or 869 million km from Earth, Juno is currently more than 48 light-minutes away, with a corresponding lag time as transmissions reach NASA's worldwide Deep Space Network.

Launched on August 5, 2011, from Cape Canaveral atop an Atlas V rocket, Juno took almost five years and one Earth gravitational assist flyby (on October 9, 2013) to reach Jupiter.

Juno is the second in the series of three New Frontiers program missions for NASA: the first was theNew Horizons mission to Pluto and beyond (launched in 2006), and the next is the Origins Spectral Interpretation Resource Identification Security REgolith Explorer (OSIRIS-REx) asteroid sample-return mission, now being readied for launch in September.


Juno's looping initial orbit keeps it well clear of the most intense charged-particle belt trapped around the planet. It also means that the spacecraft won't return to the planet's immediate vicinity until August 27th. On October 19th, Juno will fire its main engine one final time to drop the spacecraft into a series of tighter, 14-day-long science orbits. Juno also revved its rotation up from two to five revolutions per minute during today's orbital insertion maneuver. Spinning the spacecraft allows for stabilization without the use of reaction wheels. The very first spacecraft to explore Jupiter — Pioneers 10 and 11 in the early 1970s — utilized the same approach.

The Juno Probe's Dangerous Assignment
The mission's three major objectives are to study Jupiter's polar magnetosphere, assess the composition of its atmosphere, and probe its deep interior. To accomplish this, the spacecraft must duck under the planet's intense radiation belt and thread a target zone just above its cloudtops.


A '"first quarter Jupiter" and its large moons, snapped by JunoCam on June 21, 2016, when the spacecraft was still 10.9 million km (6.8 million miles) from Jupiter.
NASA / JPL / SwRI / MSSS

Juno will plunge closer to the Jovian cloud tops than any mission before, passing just 4,200 km (2,600 miles) away over the course of 36 orbits. Its instruments will also examine Jupiter's polar regions close up on each successive close pass, another first.


Initial and science orbits for Juno.
NASA / JPL

 

Juno Overview
Unlocking Jupiter's Secrets




Juno will improve our understanding of the solar system's beginnings by revealing the origin and evolution of Jupiter.

Specifically, Juno will…

• Determine how much water is in Jupiter's atmosphere, which helps determine which planet formation theory is correct (or if new theories are needed)
• Look deep into Jupiter's atmosphere to measure composition, temperature, cloud motions and other properties
• Map Jupiter's magnetic and gravity fields, revealing the planet's deep structure
• Explore and study Jupiter's magnetosphere near the planet's poles, especially the auroras – Jupiter's northern and southern lights – providing new insights about how the planet's enormous magnetic force field affects its atmosphere.

The Giant Planet Story is the Story of the Solar System


Artist concept of Juno
Credits: NASA/JPL-Caltech

Juno's principal goal is to understand the origin and evolution of Jupiter. Underneath its dense cloud cover, Jupiter safeguards secrets to the fundamental processes and conditions that governed our solar system during its formation. As our primary example of a giant planet, Jupiter can also provide critical knowledge for understanding the planetary systems being discovered around other stars.

With its suite of 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.

Juno 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.

Jupiter's Origins and Interior


Artist concept of a young star system similar to our own.
Credits: NASA/JPL-Caltech


T. Pyle (SSC) Theories about solar system formation all begin with the collapse of a giant cloud of gas and dust, or nebula, most of which formed the infant sun. Like the sun, Jupiter is mostly hydrogen and helium, so it must have formed early, capturing most of the material left after our star came to be. How this happened, however, is unclear. Did a massive planetary core form first and gravitationally capture all that gas, or did an unstable region collapse inside the nebula, triggering the planet's formation? Differences between these scenarios are profound.

Even more importantly, the composition and role of icy planetesimals, or small proto-planets, in planetary formation hangs in the balance – and with them, the origin of Earth and other terrestrial planets. Icy planetesimals likely were the carriers of materials like water and carbon compounds that are the fundamental building blocks of life.

Unlike Earth, Jupiter's giant mass allowed it to hold onto its original composition, providing us with a way of tracing our solar system's history. Juno will measure the amount of water and ammonia in Jupiter's atmosphere and determine if the planet actually has a solid core, directly resolving the origin of this giant planet and thereby the solar system. By mapping Jupiter's gravitational and magnetic fields, Juno will reveal the planet's interior structure and measure the mass of the core.

Atmosphere

How deep Jupiter's colorful zones, belts, and other features penetrate is one of the most outstanding fundamental questions about the giant planet. Juno will determine the global structure and motions of the planet's atmosphere below the cloud tops for the first time, mapping variations in the atmosphere's composition, temperature, clouds and patterns of movement down to unprecedented depths.

Magnetosphere

Deep in Jupiter's atmosphere, under great pressure, hydrogen gas is squeezed into a fluid known as metallic hydrogen. At these great depths, the hydrogen acts like an electrically conducting metal which is believed to be the source of the planet's intense magnetic field. This powerful magnetic environment creates the brightest auroras in our solar system, as charged particles precipitate down into the planet's atmosphere. Juno will directly sample the charged particles and magnetic fields near Jupiter's poles for the first time, while simultaneously observing the auroras in ultraviolet light produced by the extraordinary amounts of energy crashing into the polar regions. These investigations will greatly improve our understanding of this remarkable phenomenon, and also of similar magnetic objects, like young stars with their own planetary systems.

Learn more about the motivation behind Juno at the mission website.

Juno's Mythical Connection

In Greek and Roman mythology, Jupiter drew a veil of clouds around himself to hide his mischief. It was Jupiter's wife, the goddess Juno, who was able to peer through the clouds and reveal Jupiter's true nature. The Juno spacecraft will also look beneath the clouds to see what the planet is up to, not seeking signs of misbehavior, but helping us to understand the planet's structure and history.

Mission Timeline

• Launch - August 5, 2011
• Deep Space Maneuvers - August/September 2012
• Earth flyby gravity assist - October 2013
• Jupiter arrival - July 2016
• Spacecraft will orbit Jupiter for 20 months (37 orbits)
• End of mission (deorbit into Jupiter) - February 2018

The Juno mission is the second spacecraft designed under NASA's New Frontiers Program. The first is the Pluto New Horizons mission, which flew by the dwarf planet in July 2015 after a nine-and-a-half-year flight. The program provides opportunities to carry out several medium-class missions identified as top priority objectives in the Decadal Solar System Exploration Survey, conducted by the Space Studies Board of the National Research Council in Washington.

JPL manages the Juno mission for the principal investigator, Scott Bolton, of Southwest Research Institute in San Antonio. The Juno mission is part of the New Frontiers Program managed at NASA's Marshall Space Flight Center in Huntsville, Ala. Lockheed Martin Space Systems, Denver, built the spacecraft. Launch management for the mission is the responsibility of NASA's Launch Services Program at the Kennedy Space Center in Florida. JPL is a division of the California Institute of Technology in Pasadena.

 

Here is how Juno will study Jupiter
Juno is equipped with 9 scientific instruments all dedicated to studying the largest planet in the solar system.
By Jordan Rice | Published: Tuesday, July 05, 2016

A complete overview of all of Juno's science instruments and their placement on the spacecraft
NASA
Juno launched from Cape Canaveral, Florida on August 5th, 2011 on board an Atlas V-551 rocket and reached Jupiter on July 4th, 2016. Juno's mission is to study Jupiter by orbiting the planet 32 times during its life passing as close as 5,000 km to the upper-most layers.

As the spacecraft is in a polar orbit around the planet, this is the prime spot for studies into the gravitational and magnetic fields of Jupiter. Juno will precisely map the gravitational field to determine how the mass is distributed throughout the planet as well as properties of its structure. Juno will also map the magnetic field to try and determine its origin and structure as well as how far deep in the planet the field is created.

Another key part of the mission is to determine the ratio of oxygen to hydrogen. In other words, to figure out how much water actually exists in the planet which will hopefully give us insight into how the solar system was formed. Juno will also better estimate Jupiter's core mass to see how the planet formed in regards to the rest of the solar system.

Mapping every possible element of the cloud layers is also very important; such as mapping the temperature, opacity, composition, structure, and dynamics of the cloud layers at all latitudes. As Jupiter has a strong magnetic field, Juno is going to explore the 3-D structure of the magnetosphere and its accompanying auroras.

The nine instruments that will achieve Juno's science objectives are; the Microwave Radiometer (MWR), Jovian Infrared Auroral Mapper (JIRAM), Magnetometer (MAG), Gravity Science (GS), Jovian Auroral Distributions Experiment (JADE), Jovian Energetic Particle Detector Instrument (JEDI), Radio and Plasma Wave Sensor (Waves), Ultraviolet Imaging Spectrograph (UVS), and JunoCam (JCM).



Showing the six antennas on Juno's MWR instrument
NASA/JPL/Caltech
The MWR has six antennas that will each pick up a certain wavelength in the microwave range; 600 MHz, 1.2 GHz, 2.4 GHz, 4.8 GHz, 9.6 GHz, and 22 GHz. These wavelengths correspond to the only microwaves that can escape Jupiter's thick atmosphere. The radiometer will me measuring the amount of ammonia and water in the deeper layers of the Jovian atmosphere at about 500 to 600 km. Combining the data from both of these devices, it is possible to get a temperature profile at different depths.


The JIRAM instrument on Juno
ASI/IFSI
The JIRAM will conduct its studies to the upper layers at around 50 to 70 km deep. It will provide images of the aurora as well as see how the water and clouds are moving beneath the upper layers. JIRAM can also detect other important molecules like water vapor, methane, and phosphine.


The magnetometer boom on Juno



NASA/JPL/Caltech
There are two parts to the magnetometer, the Flux Gate Magnetometer (FGM) and the Advanced Stellar Compass (ASC). The FGM measures the strength and direction of the magnetic field lines while the ASC monitors the orientation of the FGM sensor. The magnetometer has a very important job as its data will be used to help map the magnetic field around Jupiter, reveal clues to the dynamics of the planet's interior, and make a 3-D structure of the polar magnetosphere.


Juno's high gain antenna on the GS instrument

NASA/JPL/Caltech
The purpose of the GS is to study and map the distribution of mass inside the planet by using small variations in gravity in Jupiter's orbit.


JADE-E & JADE-I on Juno
NASA/SwRI
JADE's mission is to measure the energy and velocity vector of the low energy ions and electrons in Jupiter's aurora.


Sensor Head Design for the JEDI instrument on Juno
NASA/JHU
While JEDI's mission is to measure the energy and velocity vector of the high energy ions and electrons in the polar magnetosphere.


The Waves instrument will be surveying the plasma and radio spectra in the auroras to look at the acceleration of the particles in the aurora.


The UVS instrument on Juno

SwRI
As the spacecraft is spinning, the UVS will be recording the wavelength and arrival time of the ultraviolet photons that pass through the instrument's slit as it turns toward and away from the planet. It will also provide ultraviolet images of the auroras.


The JunoCam on Juno
NASA
The final instrument aboard Juno is the JunoCam. This instrument is purely educational and designed for public outreach. JunoCam will only function for about seven orbits around the planet as the harsh radiation field's of Jupiter will slowly destroy it. It will take the first post-orbit photo around August 27th.

 

Concerns about the health of the Juno spacecraft’s main engine have compelled NASA managers to keep the research probe in its current arcing, high-altitude orbit around Jupiter, a decision that will delay the full science return from the $1.1 billion mission but should still allow it to meet all predetermined objectives.

Juno fired its main engine to brake into orbit around Jupiter on July 4, 2016, maneuvering into an egg-shaped 53-day orbit that takes the spacecraft several million miles from the giant planet on each circuit.

At the low end of the orbit, the spacecraft passes within 3,000 miles (5,000 kilometres) from Jupiter’s cloud tops, permitting Juno’s instruments to peer deep into the atmosphere, measure the planet’s extreme magnetic field and radiation belts, observe its auroras, and take the first detailed images of its poles.

But engineers called off another engine burn planned for Oct. 19 to put Juno in a tighter 14-day orbit, the science perch envisioned by mission managers since the project’s inception. Most of Juno’s scientific observations occur when the probe is closer to the planet, and the 14-day orbit was designed to give researchers rapid-fire data returns during close approaches every two weeks.

Ground controllers noticed two helium check valves inside the spacecraft’s main propulsion system did not behave as expected during pressurization of Juno’s propellant tanks about a week before the planned Oct. 19 engine firing. The valves opened in several seconds before previous engine burns, but took several minutes to open in October.

Rick Nybakken, Juno’s project manager at NASA’s Jet Propulsion Laboratory, told Spaceflight Now that engineers recommended canceling the maneuver and keeping the craft in its current 53-day orbit after a multi-month investigation.

“The project recommended not doing the burn,” Nybakken said in a Feb. 17 interview. “We’re in a great science orbit, the spacecraft is healthy, the instruments are healthy. We’re getting incredible science, and it’s teaching us more about Jupiter, and there are a lot of very interesting surprises about Jupiter, so we recommended not to take any additional risk that might jeopardize that — not to do this burn — and ultimately NASA Headquarters agreed with that recommendation.”



Engineers ruled out any link between Juno’s propulsion problem and engine failures on two geostationary communications satellites last year, Nybakken said.

The commercial Intelsat 33e and the U.S. Navy’s MUOS 5 communications satellites were to use on-board engines to raise their orbits to geostationary altitude 22,300 miles (35,800 kilometres) above Earth’s equator after launching in June and August 2016. Both satellites had to use backup thrusters to finish the job.

Nybakken said those engine failures were unrelated to the issue aboard Juno, and engineers with JPL and Lockheed Martin — Juno’s prime contractor — cleared the Leros 1b engine on the Jupiter orbiter in October, before encountering the sticky check valves.

“There were a couple of failures last fall that we looked into, and we were able to determine that those failures did not represent any sort of increased risk to Juno,” Nybakken said. “And after we completed that investigation, we were, in fact, planning to go ahead with this maneuver.”

One benefit of Juno’s predicament is the higher 53-day orbit will keep the spacecraft away from the worst of Jupiter’s intense radiation belts, which harbour hazards that mission designers believed would limit the mission’s duration to some time in 2018.

“It turns out in the 53-day orbits, we cross the equator, where the radiation belts are, much farther out, so we have much less radiation dose,” Nybakken said. “Of course, with the orbits being larger, the dose as a function of time is much slower as well.”

Juno’s next close pass by Jupiter is set for March 27, completing its fifth orbit of the planet since last year’s arrival.

“Juno is healthy, its science instruments are fully operational, and the data and images we’ve received are nothing short of amazing,” said Thomas Zurbuchen, associate administrator for NASA’s science mission directorate in Washington, in a statement. “The decision to forego the burn is the right thing to do — preserving a valuable asset so that Juno can continue its exciting journey of discovery.”

The Juno mission is funded through July 2018, for a total of 12 science orbits, down from the 32 science orbits originally planned, NASA said in a statement.

Juno’s science team can then propose to continue the mission for another two years as part of NASA’s senior review process, in which a panel of independent researchers recommend to the agency which of its planetary science missions should continue to receive federal funding.

“Juno is providing spectacular results, and we are rewriting our ideas of how giant planets work,” said Scott Bolton, the mission’s principal investigator from the Southwest Research Institute in San Antonio. “The science will be just as spectacular as with our original plan.”

“We’re very excited about what we’ve seen so far, and every time we fly by the planet it’s like Christmas time,” Nybakken said. “The data is stunning.”























Juno made its closest approach at 4:52 a.m. EDT (0852 GMT), skimming 2,700 miles (4,400 kilometers) above Jupiter's cloud tops while traveling about 129,000 mph (208,000 km/h) relative to the planet, NASA officials said.

All eight of the spacecraft's science instruments were up and running during the flyby, collecting data about Jupiter's atmosphere, gravity and electromagnetic fields. Meanwhile, the spacecraft's JunoCam took close-up color photos of the mysterious and massive planet.