Tag Archives: Jupiter

Juno successfully completes engine burn with smaller thrusters

Having successfully left safe mode, engineers had Juno do a 31 minute engine burn on Tuesday to adjust its orbit using its smaller thrusters.

The burn, which lasted just over 31 minutes, changed Juno’s orbital velocity by about 5.8 mph (2.6 meters per second) and consumed about 8 pounds (3.6 kilograms) of propellant. Juno will perform its next science flyby of Jupiter on Dec. 11, with time of closest approach to the gas giant occurring at 9:03 a.m. PDT (12:03 p.m. EDT). The complete suite of Juno’s science instruments, as well as the JunoCam imager, will be collecting data during the upcoming flyby.

That they will definitely collect data during the December 11 flyby means that they are going to delay again the main engine burn that will reduce the spacecraft’s orbit to 14 days, its official science orbit. This also means that they are still uncomfortable firing that main engine. It is also not clear from the press release whether this burn was planned, or was added to compensate for the main engine issues.

The vagueness makes me think that Juno has some serious issues that they haven’t yet told us about.

The storms of Jupiter’s south pole

storms on Jupiter

Cool image time! Even though Juno has been unable to gather any additional data since its first close approach of Jupiter in August because of technical problems, the science team has set up its website to allow the public to download the images produced so far, process those images, and then upload them to the site for the world to see.

The image to the right, reduced in resolution to show here, is one example of the many different processed images produced by interested members of the general public. It highlights the seemingly incoherent storms that are raging at Jupiter’s south pole.

close-up of storms

To the left is a cropped section of the full resolution image. It shows the complex transition zone between the darker polar regions and the brighter band that surrounds it. This chaotic atmospheric behavior is something that no climate scientist has ever seen before. It will take decades of research to untangle and even begin to understand what is happening.

Juno enters safe mode prior to Jupiter close approach

Because Juno entered safe mode prior to its close approach of Jupiter today, no science data was gathered.

NASA’s Juno spacecraft entered safe mode Tuesday, Oct. 18 at about 10:47 p.m. PDT (Oct. 19 at 1:47 a.m. EDT). Early indications are a software performance monitor induced a reboot of the spacecraft’s onboard computer. The spacecraft acted as expected during the transition into safe mode, restarted successfully and is healthy. High-rate data has been restored, and the spacecraft is conducting flight software diagnostics. All instruments are off, and the planned science data collection for today’s close flyby of Jupiter (perijove 2), did not occur. “At the time safe mode was entered, the spacecraft was more than 13 hours from its closest approach to Jupiter,” said Rick Nybakken, Juno project manager from NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “We were still quite a ways from the planet’s more intense radiation belts and magnetic fields. The spacecraft is healthy and we are working our standard recovery procedure.”

This problem, combined with the thruster valve problem that prevented engineers from putting the spacecraft into its proper 14-day science orbit today, is significantly delaying science operations. They will not be able to adjust the orbit again until its next close approach December 11 (assuming the thruster problem has been solved by then), and until then it will also not be able to do much science.

Problems with Juno’s main engine

Valve problems detected during Juno’s orbital insert around Jupiter has caused engineers to delay the October 19 engine burn that would have lowered the probe’s orbit around Jupiter.

Mission managers for NASA’s Juno mission to Jupiter have decided to postpone the upcoming burn of its main rocket motor originally scheduled for Oct. 19. This burn, called the period reduction maneuver (PRM), was to reduce Juno’s orbital period around Jupiter from 53.4 to 14 days. The decision was made in order to further study the performance of a set of valves that are part of the spacecraft’s fuel pressurization system. The period reduction maneuver was the final scheduled burn of Juno’s main engine. “Telemetry indicates that two helium check valves that play an important role in the firing of the spacecraft’s main engine did not operate as expected during a command sequence that was initiated yesterday,” said Rick Nybakken, Juno project manager at NASA’s Jet Propulsion Laboratory in Pasadena, California. “The valves should have opened in a few seconds, but it took several minutes. We need to better understand this issue before moving forward with a burn of the main engine.”

Because of this, they will instead use this next close approach to Jupiter to do pure science, something that they would not have done during the engine burn. Though this is a good example of turning lemons into lemonade, it will not be a good thing if Juno can never reduce its orbit to 14 days. A 53 day orbit will mean that they can only do good research every two months, and will seriously limit what they can learn over the long run.

First science results from Juno

Storms at Jupiter's pole

The Juno science team today released the mission’s first science results gathered during its first close fly-by of Jupiter.

I have cropped on the right one of their full images to focus in on two of the strangely shaped storms Juno imaged during its pass. This image is of the northern pole. They also have some fascinating images of the south pole storms as well. Unlike the equatorial regions, which on gas giants have what appear to be parallel coherent bands of weather, the poles appear very chaotic, with the storms forming shapes that have not been seen in any other atmosphere in the solar system. They also found a hexagon-shaped weather feature in the pole.

The first link above also included data from the spacecraft’s other instruments, showing the gas giant’s complex atmosphere in a variety of other wavelengths.

Juno’s closest Jupiter fly-by

Jupiter by Juno

Juno today successfully completed its first and closest fly-by of Jupiter during its primary mission, zipping only 2,600 miles above the gas giant’s cloud tops.

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. “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.”

While results from the spacecraft’s suite of instruments will be released down the road, a handful of images from Juno’s visible light imager — JunoCam — are expected to be released the next couple of weeks. Those images will include the highest-resolution views of the Jovian atmosphere and the first glimpse of Jupiter’s north and south poles. “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.

The image to the right, cropped and reduced in resolution to show here, was taken today when the spacecraft was still 437,000 miles away.

Io’s atmosphere freezes and reinflates daily

New data from the ground-based Gemini telescope suggests that Io’s sulfur dioxide atmosphere freezes and then reinflates each time the moon flies through Jupiter’s shadow.

A study led by SwRI’s Constantine Tsang concluded that Io’s thin atmosphere, which consists primarily of sulfur dioxide (SO2) gas emitted from volcanoes, collapses as the SO2 freezes onto the surface as ice when Io is shaded by Jupiter. When the moon moves out of eclipse and ice warms, the atmosphere reforms through sublimation, where ice converts directly to gas.

The data is somewhat uncertain, however, as it based on only two observations.

Juno swings back towards Jupiter

Juno has now passed the farther point from Jupiter in its first orbit and has started dropping back down to the gas giant.

Juno arrived at Jupiter on July 4, firing its main rocket engine as planned for 35 minutes. The flawless maneuver allowed Jupiter’s gravity to capture the solar powered spacecraft into the first of two 53.4-day-long orbits, referred to as capture orbits. Following the capture orbits, Juno will fire its engine once more to shorten its orbital period to 14 days and begin its science mission.

But before that happens, on Aug. 27, Juno must finish its first lap around Jupiter, with a finish line that represents the mission’s closest pass over the gas giant. During the encounter, Juno will skim past Jupiter at a mere 2,600 miles (4,200 kilometers) above the cloud tops.

Great Red Spot hottest spot on Jupiter

Jupiter’s Great Red Spot, a giant storm that has been raging for at least three centuries, turns out to be the hottest spot on Jupiter.

They suspect that the spot is heated from below, but really understand much else, or even that.

Juno is specifically designed to study the weather patterns of Jupiter, so we will get some of these answers, plus a lot more questions, in the coming years as the spacecraft gathers its data.

The first Juno picture of Jupiter from orbit

Juno's first picture in orbit

The Juno science team have released the first image since the spacecraft entered orbit around Jupiter. I have posted a cropped version on the right, showing only the moon Io. The full image shows Europa and Ganymede as well.

The image was taken from almost 3 million miles away, which accounts for its fuzziness. Expect much better pictures when the spacecraft dips down close in late August.

Juno has entered Jupiter’s magnetic field

After five years of travel, Juno last Friday entered Jupiter’s gigantic and very powerful magnetic field in its approach for its July 4 orbital insertion.

Meanwhile, they have uploaded to the spacecraft its final software commands for that orbital insertion.

At about 12:15 pm PDT today (3:15 p.m. EDT), mission controllers will transmit command product “ji4040” into deep space, to transition the solar-powered Juno spacecraft into autopilot. It will take nearly 48 minutes for the signal to cover the 534-million-mile (860-million-kilometer) distance between the Deep Space Network Antenna in Goldstone, California, to the Juno spacecraft. While sequence ji4040 is only one of four command products sent up to the spacecraft that day, it holds a special place in the hearts of the Juno mission team. “Ji4040 contains the command that starts the Jupiter Orbit insertion sequence,” said Ed Hirst, mission manager of Juno from NASA’s Jet Propulsion Laboratory in Pasadena, California. “As soon as it initiates — which should be in less than a second — Juno will send us data that the command sequence has started.”

Hubble images Jupiter and its aurora

Jupiter and its aurora

Cool image time! In anticipation of the arrival of Juno in orbit around Jupiter on July 4, scientists have released a spectacular image of Jupiter and its aurora, taken by the Hubble Space Telescope. The image on the right has been reduced slightly to fit on the webpage.

The main focus of the imaging is the aurora.

To highlight changes in the auroras, Hubble is observing Jupiter almost daily for several months. Using this series of far-ultraviolet images from Hubble’s Space Telescope Imaging Spectrograph, it is possible for scientists to create videos that demonstrate the movement of the vivid auroras, which cover areas bigger than the Earth.

Not only are the auroras huge in size, they are also hundreds of times more energetic than auroras on Earth. And, unlike those on Earth, they never cease. While on Earth the most intense auroras are caused by solar storms — when charged particles rain down on the upper atmosphere, excite gases, and cause them to glow red, green, and purple — Jupiter has an additional source for its auroras.

The strong magnetic field of the gas giant grabs charged particles from its surroundings. This includes not only the charged particles within the solar wind, but also the particles thrown into space by its orbiting moon Io, known for its numerous and large volcanos.

I have embedded below the fold one of the videos of the aurora, taken over time by Hubble. Quite amazing.
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Juno closing in on Jupiter

Jupiter from Juno

On Friday the Juno science team released a new image of Jupiter taken by the spacecraft from about 6.8 million miles away.

The reduced resolution image on the right is cropped but with the colors enhanced to bring out the four Galilean moons, Ganymede, Callisto, Europa, and Io. The website notes that “Juno is approaching over Jupiter’s north pole, affording the spacecraft a unique perspective on the Jovian system. Previous missions that imaged Jupiter on approach saw the system from much lower latitudes, closer to the planet’s equator.”

Rendezvous and orbital insertion happens on July 4.

A possible impact on Jupiter?

On March 17 two different amateur astronomers have taken videos of a bright flash on Jupiter which suggests something had crashed into the gas giant.

March 17th’s impact, if the evidence for it holds up, becomes the fourth such event in the past decade. The largest of these occurred July 19, 2009, and it left a distinctly dark “powder burn” in Jupiter’s upper atmosphere first spotted by Australian astro-imager Anthony Wesley. That was followed by three lesser strikes on June 3, 2010 (recorded independently by Wesley and Christopher Go); on August 10, 2010 (independently seen by Masayuki Tachikawa and Kazuo Aoki); and on September 10, 2012 (seen visually by Dan Petersen and independently recorded by George Hall).

Counting the historic multiple-hit crash of Comet Shoemaker-Levy 9 in July 1994, that’s a grand total of six impacts on Jupiter in the past 22 years.

Cosmic rays cause the red in Jupiter’s Great Red Spot

New ground-based chemistry research suggests that the bombardment of cosmic rays in Jupiter’s upper atmosphere could be the cause of the red color of the gas giant’s Great Red Spot.

They found that one of the spot’s major components, ammonium hydrosulfide, breaks down when exposed to that radiation in such a way that it turns red. They also think that ultraviolet radiation, also prevalent in space, will do the same.

Juno becomes most distant solar-powered mission

Scheduled to enter orbit around Jupiter in July 2016, the American space probe Juno has now broken the record as the most distant solar-powered interplanetary spacecraft ever to operate.

The previous record had been held by Rosetta. In the past most missions beyond Mars used nuclear-generated power plants, since the amount of sunlight is insufficient. However, improvements to the efficiency of solar power, combined with a lack of nuclear fuel in the U.S., has made it possible to fly missions using solar power farther from the sun.

New weather maps of Jupiter

Using the Hubble Space Telescope astronomers have compiled a new set of maps of Jupiter, showing changes in the gas giant’s bands and spots, including the Giant Red Spot.

The scientists behind the new images took pictures of Jupiter using Hubble’s Wide Field Camera 3 over a ten-hour period and have produced two maps of the entire planet from the observations. These maps make it possible to determine the speeds of Jupiter’s winds, to identify different phenomena in its atmosphere and to track changes in its most famous features.

The new images confirm that the huge storm, which has raged on Jupiter’s surface for at least three hundred years, continues to shrink, but that it may not go out without a fight. The storm, known as the Great Red Spot, is seen here swirling at the centre of the image of the planet. It has been decreasing in size at a noticeably faster rate from year to year for some time. But now, the rate of shrinkage seems to be slowing again, even though the spot is still about 240 kilometres smaller than it was in 2014.

Juno flight plan at Jupiter revised

In preparation for its arrival in orbit around Jupiter in about a year, engineers for the unmanned probe Juno have revised their planned orbital maneuvers.

Following a detailed analysis by the Juno team, NASA recently approved changes to the mission’s flight plan at Jupiter. Instead of taking 11 days to orbit the planet, Juno will now complete one revolution every 14 days. The difference in orbit period will be accomplished by having Juno execute a slightly shorter engine burn than originally planned.

The revised cadence will allow Juno to build maps of the planet’s magnetic and gravity fields in a way that will provide a global look at the planet earlier in the mission than the original plan. Over successive orbits, Juno will build a virtual web around Jupiter, making its gravity and magnetic field maps as it passes over different longitudes from north to south. The original plan would have required 15 orbits to map these forces globally, with 15 more orbits filling in gaps to make the map complete. In the revised plan, Juno will get very basic mapping coverage in just eight orbits. A new level of detail will be added with each successive doubling of the number, at 16 and 32 orbits.

The change will extend the official mission from 15 to 20 months, though I expect that even this will be extended if the spacecraft’s fuel holds out.

Is the dark material along Europa’s long surface fissures sea salt?

The uncertainty of science: By creating what they call “Europa in a can” here on Earth, scientists have determined that the dark material that appears to have seeped out of Europa’s long linear fractures might be sea salt from the underground ocean, turned brown by the harsh radiation hitting the moon’s surface.

This result is quite intriguing, but the only thing certain about it is its uncertainty. The only way we will know what this brown material really is will be to go there again with much better equipment and study the material itself

Ganymede’s underground salt water ocean

By measuring the interaction of Jupiter and Ganymede’s magnetic fields, scientists have been able to estimate the size of the salt water ocean in Ganymede’s interior.

A team of scientists led by Joachim Saur of the University of Cologne in Germany came up with the idea of using Hubble to learn more about the inside of the moon. “I was always brainstorming how we could use a telescope in other ways,” said Saur. “Is there a way you could use a telescope to look inside a planetary body? Then I thought, the aurorae! Because aurorae are controlled by the magnetic field, if you observe the aurorae in an appropriate way, you learn something about the magnetic field. If you know the magnetic field, then you know something about the moon’s interior.”

If a saltwater ocean were present, Jupiter’s magnetic field would create a secondary magnetic field in the ocean that would counter Jupiter’s field. This “magnetic friction” would suppress the rocking of the aurorae. This ocean fights Jupiter’s magnetic field so strongly that it reduces the rocking of the aurorae to 2 degrees, instead of 6 degrees if the ocean were not present. Scientists estimate the ocean is 60 miles (100 kilometers) thick — 10 times deeper than Earth’s oceans — and is buried under a 95-mile (150-kilometer) crust of mostly ice.

That’s more water than contained in all of Earth’s oceans.

Hubble gives Jupiter a giant eye

Jupiter's Giant Eye

By timing things perfectly, scientists have used the Hubble Space Telescope to take a very cool image of Jupiter, with the shadow of its largest moon Ganymede cast into the planet’s Giant Red Spot.

The science from this image is somewhat limited, but damn, it sure is a neat demonstration of our modern ability to do amazing things with technology.

Click on the link for the full image.

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