At 12:25 on August 5, 2011, the Juno Jupiter probe came from Florida, USACape CanaveralIgnite and lift off, start the expeditionJupiterJourney.
At 2:00 p.m. on January 13, 2016 (3:00 a.m. on January 14, Beijing time), the American Juno broke the record for the longest voyage of a solar powered probe. At that time, it was about 793 million kilometers away from the sun, compared with about 150 million kilometers from the Earth to the sun.
At noon on July 5, 2016 Beijing time, NASA held a press conference to announce thatSpaceJuno, which has been flying for 4 years and 11 months, successfully entered the orbit of Jupiter. This is the first probe to orbit Jupiter in 13 years since Galileo ended its exploration mission in 2003.[1]
Scientific objectives
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The scientific instrument kit carried by Juno will[2]：
Determining the ratio of hydrogen and oxygen and effectively measuring the abundance of water on Jupiter will help to clarify where Jupiter, the gas giant in the current theory, formed in the solar system.
A better assessment of Jupiter's core mass will also help clarify the current theory of where gas giants formed in the solar system.
Precisely draw Jupiter's gravitational field map to determine the internal mass distribution of Jupiter, including its structural and dynamic properties.
Precise mapping of Jupiter's magnetic field, evaluation of its origin and structural field, and creation of magnetic field in many depths of Jupiter.This experiment will also help scientists understand the generator principle of basic physics.
The atmospheric composition, temperature, structure, cloud opacity and dynamic changes are mapped, and the pressure exceeds 100 Pa (10 MPa; 1450 psi) at all latitudes.
Explore the three-dimensional structure and characteristics of Jupiter's polar magnetosphere and aurora.
A new test to measure the reference frame drag caused by Jupiter's angular momentum, also known as the Lenzer Tilling precession, and the possible general relativity effect connected with Jupiter's rotation.
Origin of name
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The name of the detector "Juno" is the wife of Jupiter, the god in Roman mythology.Jupiter used his magic to cover himself with clouds, but Juno could see through these clouds and understand Jupiter's true face. Therefore, the name of the detector was also borrowed from its meaning, hoping that it could unlock the hidden secrets of this gas giant planet surrounded by clouds and fog.
Detection history
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The Juno Jupiter probe has a total cruise distance of more than 716 million kilometers and a speed of more than 165000 miles per hour (about 264000 km/h).In one Earth year, it will orbit Jupiter 33 times.
After the launch on August 5, 2011, Juno's cruise route will first start from EarthGravity boosting, and meet the earth again two years later (October 2013).
“Juno”At 12:25 on August 5, 2011JupiterIt must be in an appropriate position so that "Juno" can reach the destination.The probe will fly to Jupiter by gravity in October 2013, and is expected to reach the orbit of Jupiter in 2016 to investigate whether there are ice cores on Jupiter;Determine the content of water on Jupiter;Ammonia content in the atmosphere;Study JupiterAtmospheric convectionAnd discuss the origin of Jupiter's magnetic field and the polar regionMagnetosphereThe mission is scheduled to end in October 2017.During the exploration of Jupiter, the probe will suffer strongcosmic raysThe intensity of the radiation is higher than that of any place in the solar system visited by detectors except the sun.According to the plan,Juno Arrive at Jupiter, which will circle thisgas giant During the mission, we flew 33 circles around Jupiter, and used polar orbit to fly around from the North Pole to the South Pole.This spaceship is equipped with 8 sets of load equipment for investigationJupiterAtmosphere,gravitational fieldAnd magnetic field.[3]
In July 2015, NASA released a message thatInterplanetary spaceThe Juno probe, which has been flying for four years in China, is expected to arrive at Jupiter on July 4, 2016.[4]
In 2016, it will conduct orbit entry ignition, slow down the speed and enter the 11 day polar orbit.
At 2:00 p.m. on January 13, 2016 (3:00 a.m. on January 14, Beijing time), the American Juno broke the record for the longest voyage of a solar powered probe. At that time, it was about 793 million kilometers away from the sun, compared with about 150 million kilometers from the Earth to the sun.[5]
The National Aeronautics and Space Administration (NASA) announced that the Juno Jupiter probe willUS Eastern TimeOn the evening of July 4, 2016, it entered the orbit of Jupiter, ending its nearly five-year long journey.[6]
On July 5, 2016 Beijing time,U.S.ANASA's Juno spacecraft has successfully entered the orbit around Jupiter, and will start the mission of exploring the origin of Jupiter.[7]Juno will orbit Jupiter for 20 months, collect data about the planet's core, describe its magnetic field, and measure the content of water and ammonia in the atmosphere.In addition, Juno will also observe the famous Great Red Spot on the surface of Jupiter, a storm that has lasted for hundreds of years, to reveal its deep secrets.[7]
At 20:51 on August 27, Beijing time, the Juno probe of the United States reached a wooden point 4200 kilometers above Jupiter's cloud layer, and at a speed of 208000 kilometers/hour, captured the highest resolution image of Jupiter's giant cloud layer ever.[8]
Juno currently orbits Jupiter every 53 days.It was originally planned to start the engine on October 19 to change its orbit, so as to reduce the orbital period to one circle around Jupiter every 14 days.However, due to a problem with the engine valve, the Juno team will delay the ignition of the engine until the problem is fixed.[9]The mission team ignited the auxiliary thruster for 31 minutes and fine tuned the flight speed of the detector.On the same day, the computer was restarted due to software performance problems, resulting in the detector entering a protective "safe mode".After "consultation" and repair by the mission team, the "Juno", which was temporarily "stuck", resumed its work and will complete the flying mission near the wooden point on December 11.[10]
On February 2, 2017, NASA's Juno spacecraft successfully flew over Jupiter for the fourth time.The Juno probe reached the closest distance to Jupiter, about 4300 kilometers away from Jupiter's top clouds.Juno detector8 scientific surveying equipment and Juno camera have collected a lot of data in this survey, which has been transmitted to the earth at present.[11]
In October 2016, NASA Juno probe, which arrived in Jupiter orbit, failed when preparing to maneuver to low orbit, and the orbital maneuver mission has been postponed. On February 18, 2017, after assessing various risks, NASA decided to give up allowing Juno probe to enter the lower 14 day Jupiter cycle orbit, and it will continue to maintain the current 53 day cycle of scientific orbit and conduct more scientific research missions.[12]
On February 21, 2017, the National Aeronautics and Space Administration (NASA) announced that it would abandon the landmark Jupiter probe, Juno, because it had been in the wrong orbit for too long, and the team would not find a way to put it into a more ideal orbit.[13]
On September 29, 2022, the Juno Jupiter probe of the National Aeronautics and Space Administration (NASA) flew 352 kilometers above Europa, the Jupiter satellite, and took the closest picture for it in the past 20 years.[26]
On December 30, 2023, Juno spacecraft will fly over Io at close range, which will be the shortest distance for the spacecraft to fly over this satellite in more than 20 years. At that time, it will be only 1500 kilometers away from the surface of Io.[28]
Function configuration
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“Juno”By the United StatesLockheed MartinBuilt by the company, subordinate to NASAJet Propulsion LaboratoryBe responsible for the operation of the whole detection task.Juno isNASAThe second exploration project planned to be implemented by "Xinjiang Boundary".
Juno Jupiter probe
“Juno”The probe carried three solar panels, each 2.7 meters wide and 10 meters long, the size of a tractor trailer.Within an hour after liftoff, three solar panels will slowly unfold, which makes Juno look like a giantwindmillThe media vividly called these three solar panels "solar energywing”。April 2017, that is, aroundJupiterNine months after orbital flight, Juno will surpassEuropean Space AgencyRosettaComet detectorAnd become the spacecraft with the longest flight mileage relying solely on solar power.
“Juno”The No. 1 solar panel can provide 14 kilowatts of power, but after entering the orbit of Jupiter, the power provided is only 400 watts, and only a few light bulbs can be lit.Therefore, the scientific instruments and airborne computers on Juno are highly energy-saving. At the same time, the research team has carefully designed the orbit around Jupiter for Juno to receive as much sunlight as possible.[14]
Carrying equipment
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Detection equipment
“Juno”It is equipped with 9 detection equipment, including a wide-angleColor camera, can send back color images to the earth.WhenJuno After entering orbit, infrared and microwave detection instruments will measure the thermal radiation sources from the deep atmosphere of Jupiter.These observations will supplement and confirm the previousJupiterThe study of composition includes the detection of water and oxygen distribution.In addition, it will help to understand the origin of Jupiter.Juno will also study the circulation that causes many forms and phenomena in Jupiter's atmosphere.At the same time, other instruments willgravitational fieldAnd bipolarMagnetosphereData.The entire Juno mission is scheduled to be completed in October 2017, when the spacecraft will have circled Jupiter 33 times, and will eventually leave orbit and fall into Jupiter.[15]
Test solar panel
Solar panel[16]
This solar panel has a high efficiency of light energy utilization, which also determines its huge size: 8.9 meters long and 2.7 meters wide.Sufficient to power five standard bulbs ifSolar panelOptimized for the angle of the sun, it can generate up to 12-14 kilowatts of power.becauseJupiterAnd powerfulHigh-energy particleThe radiation intensity exceeds that of any place that has been visited by human probes except the sun. The radiation belt starts from the equator of Jupiter and passes throughEuropaEuropa, outward expansion 650000 km, includingSolar panelAll kinds of internal and external devices shall be well shielded to withstand strong X-ray exposure.
Juno will also use its communication equipment to investigate Jupiter's gravity field, which is part of its "gravity science experiment" project.By sending a signal back to Earth and observing its Doppler effect, scientists will be able to investigate the impact of Jupiter's gravity field on the signal.
Education plan
As part of the public education plan, the Juno probe will also fly to Jupiter with three Lego dolls. These three little people are Jupiter, the god in Roman mythology, Juno, Jupiter's wife, and Galileo, the famous Italian astronomer,He has made important pioneering contributions to the observation of Jupiter, including the discovery of the four largest satellites of Jupiter, which are now called "Galilean satellites".
In fact, the first probe orbiting Jupiter was named "Galileo". In addition, this Juno probe will also carry a plate of Galileo's proverbs provided by the Italian Space Agency, with Galileo's head and the original notes recorded when Galileo observed Jupiter.[17]
Scientific payload of Juno spacecraft
The loads carried by Juno spacecraft include 29 sensors, which transmit data to 9 loads.Eight scientific loads including MAG, MWRz, gravity science, WAVES, JEDI, JADE, UVS and JIRAM equipment are classified as scientific loads;The last JunoCam camera is mainly a load for educational and public publicity purposes.
Because Juno uses a large elliptical orbit, it is sometimes far away from Jupiter and sometimes very close when it runs, so most of the scientific exploration tasks will be carried out within about three hours when the orbit is closest to Jupiter. Of course, calibration, some remote observation, magnetic field detection and other scientific exploration work will also be carried out at other positions in the orbit.[18]
As early as 1989, the United States had launched a Galileo probe, which arrived at Jupiter in 1995 and began to revolve around Jupiter.In order to study the composition of Jupiter's atmosphere, the Galileo probe also released an atmospheric probe to Jupiter.This probe had a "tragic fate". One hour after entering Jupiter's atmosphere, it was destroyed under the intense friction and strong pressure with Jupiter's atmosphere. Scientists predicted that it might be directly melted or even evaporated, and completely disappeared in Jupiter's atmosphere.This will also be the final fate of the Juno.
Although humans have previously launched the Galileo probe for close observation of Jupiter, Jupiter still has unsolved mysteries such as magnetic field, great red spot and core composition.The Juno will carry a magnetometerMicrowave radiometer、high energy particle detector And other scientific equipment to observe and study Jupiter.
Finally, the total number of known Ganymede has increased to 79.[25]There is water on Europa's surface, which makes scientists doubt whether there is primitive life form on Europa.
Today, Juno will be captured by Jupiter's gravity and become a polar orbiting satellite.After about a year of exploration, Juno will fall into Jupiter's atmosphere and complete its mission.But we can't see the image in real time.The reason for choosing such a fate is that scientists worry that Juno may pollute the satellite with primitive life.The distance delay and the signal bandwidth are too small, so we can only wait for the image returned in August, which will be the clearest "self portrait" of Jupiter ever.
People have been trying to study this planet for hundreds of years, but we still have many basic questions to answer about this gas giant planet.
JupiterHow was it formed?How much water and oxygen does Jupiter's atmosphere contain?What is the internal structure of Jupiter?Is the rotation of Jupiter more consistent with the rotation of rigid bodies, or is there rotation at different speeds at different depths inside?Does Jupiter have a solid core?If so, how big is the kernel?How did Jupiter's powerful magnetic field form?How deep do many of the atmospheric structures seen at the top of Jupiter's cloud cover extend downward? What is the relationship between it and the deep motion of Jupiter's atmosphere?What is the mechanism of Jupiter's aurora?
Beneath the thick clouds and violent storms of the giant planet, there are still many stories about the life experience of the giant planet, as well as the wholesolar systemJuno will tell us about the unsolved mysteries of history and the problems that perplex mankind.[19]
Latest information
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Recently, Jupiter was photographed by NASA's Juno spacecraft.NASA released the first batch of precious high-definition photos of Jupiter's north pole and its southern aurora.This is the clearest close-up picture of Jupiter ever seen by mankind. It was taken by the Jupiter probe Juno when it first flew over Jupiter from the nearest distance.
Juno will orbit Jupiter for 20 months, collect data about the planet's core, describe its magnetic field, and measure the content of water and ammonia in the atmosphere.In addition, Juno will also observe the famous Great Red Spot on the surface of Jupiter, a storm that has lasted for hundreds of years, to reveal its deep secrets.[20]
Juno is expected to unveil the mystery of Jupiter
On July 5, the Juno spacecraft of the United States successfully entered the orbit of Jupiter, becoming the closest spacecraft to Jupiter.Before it, eight probes, including Pioneer 10, Pioneer 11, Ulysses and Galileo, visited Jupiter.What attracts a large number of detectors?What are the highlights of this exploration mission?According to Scott Bolton, the chief researcher of the Juno project, the Juno entered a 53.5 day periodic orbit this time, rather than a 14 day periodic orbit for scientific investigation.Juno will first circle Jupiter in this orbit for two times, and then ignite the main engine again on or about October 19, entering the 14 day cycle scientific exploration orbit.In the next 20 months, Juno will fly around Jupiter 37 times and use the 9 scientific payload instruments to detect Jupiter."Through Juno, we can investigate Jupiter's huge radiation belt, learn more about the interior of the planet, how Jupiter was born, and how the entire solar system evolved." Charles Bolden, director of the National Aeronautics and Space Administration, said in the statement announcing that Juno successfully entered the orbit of Jupiter.The gravity probe on Juno will help scientists explore the internal structure of Jupiter;The magnetometer can draw a detailed three-dimensional structure map of Jupiter's magnetic field, and explore the source of the violent wind of up to 618 kilometers per hour in Jupiter;The microwave radiometer can penetrate Jupiter's clouds and penetrate into its interior to analyze the composition and movement of Jupiter's gas.Scientists believe that the data collected by Juno may make people's understanding of Jupiter, the sun, and life itself change dramatically.Beyond the meaning of science,National Astronomical Observatory, Chinese Academy of SciencesZheng Yongchun, an expert in planetary science, is also concerned about the engineering difficulty of the project.For Juno, a trip to Jupiter is not easy.We must first overcome the gravity of the earth, and after flying away from the earth, we must also overcome the gravity of the sun.After approaching Jupiter, you need to ignite the main engine and then be captured and decelerated by Jupiter's gravity to enter the orbit of Jupiter.When flying around Jupiter, you must be careful to avoid the strong radiation and debris areas around Jupiter.After 59 months of space flight and 2.7 billion kilometers, Juno successfully entered the orbit of Jupiter.In order to ensure that Juno can enter the orbit of Jupiter smoothly, NASA shut down all equipment irrelevant to the orbit entry in advance and let the probe perform the orbit entry action for 35 minutes.In order to cope with the harsh radiation environment around Jupiter, scientists have custom-made a 180 kg "titanium armor shield" for Juno. The processor and circuit on the detector have also undergone special radiation protection treatment, and the detector is orbited around Jupiter to avoid the area with the highest radiation intensity.[21]NASA has approved the update of Juno's scientific operation, which will last until July 2021.This will allow Juno to stay in orbit around Jupiter for another 41 months, enabling it to achieve its main scientific goals.[22]
On May 13, 2024, NASA released on its official website the photos taken by Juno spacecraft when it flew over Jupiter in a short distance recently, including two photos of Jupiter's small satellite, Ganymede.[29]
research findings
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Jupiter has various dark bands, which are actually clouds in the atmosphere.Because visible light cannot penetrate these clouds.We couldn't figure out what was happening below the clouds.However, Juno carries a variety of microwave equipment, which can detect the situation at different levels in the cloud.If we finally put all the results together, these instruments can help us peel off the clouds layer by layer effectively, just like peeling onions to tell us the inside of the clouds.Based on the microwave data, the artist made an imaginary picture, which revealed a distinctive feature of the cloud layer: some stripes can still be seen deep into the cloud layer.
Bolton mentioned in a speech at the Astronomical Society that none of the aurora measurements on August 27 were in line with our expectations.The detector opened a variety of detectors in the process of flying over the aurora, but what everyone expected did not appear, but what everyone did not expect came.Bolton said that they were sorting out the data.Obviously, we need to understand the complex system of Jupiter's aurora.In addition, as Juno accelerated toward Jupiter,Planetary magnetic fieldThe measured readings of are always in good agreement with the predictions of the planetary model.But in the last few minutes when the detector was about to reach the wooden point, the reading suddenly showed a huge difference from the predicted value, indicating that the actual magnetic field was much stronger than expected.
Bolton said that this means that Jupiter's internal magnetic field is far more complex than we thought.Of course, Bolton also stressed that no detector has ever been so close to Jupiter before, and Juno's mission is to collect data to test these models.More surprises came from the pilot measurement of Jupiter's gravity field.Bolton said that the Juno team members who had previously built the internal gravity field model of the planet were ready to redo the model according to the newly collected data.The gravity field inside the planet guards many secrets, and unlocking these secrets will help us better understand Jupiter.[9]
In May 2023, NASA released a tweet to share the latest photos of Io taken by JunoFilm.[27]
As of May 2023, the Juno space probe has flown more than 510 million miles and has successfully recorded three Saturnian satellites。[27]
world record
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The farthest solar spaceship:The flight distance of Juno exceeded the 791 million kilometers created by the European Space Agency Rosetta in October 2012.
The fastest spaceship:Juno's second record was set on July 4, 2016, when it was attracted by Jupiter.The huge gravity of this gas giant planet can make the moving probe speed reach 265000 kilometers per hour, which makes Juno the fastest spacecraft.[23]
The detector that can sail farthest relying on solar energy:When NASA's space probe Juno orbited Jupiter, it was 816.62 million kilometers away from the sun.(Guinness World Records)[24]
