Tag Archives: Juno

Space Sunday: Juno and Jupiter, China, Google and the Moon

An artist's impression of Juno firing its main engine at it passes over Jupiter's cloud tops. Credit: NASA

An artist’s impression of Juno firing its main engine at it passes over Jupiter’s cloud tops. Credit: NASA

On Thursday, February 1st, 2017, NASA’s Juno spacecraft completed its fourth 53.5 day orbit of Jupiter since its arrival on July 4th, 2016. The vehicle, reached perijove – the point at which it is closest to Jupiter’s cloud tops at 12:57 GMT (07:57  EST), just 4,300 km (2,670 mi) above the cloud top at a velocity of about 208,000 km/h (129,300 mph) relative to the planet.

As there were no plans to utilise the craft’s main engine to slow the craft into a 14-day orbit around Jupiter – a issue with a potentially faulty set of valves in the motor system is still being investigated – the spacecraft was able to conduct a “close-up” data gathering exercise as it swept around Jupiter, gathering data on atmospheric radiation and plasma.

Also active during the flyover was the spacecraft’s imaging system, dubbed “JunoCam”. This has already captured some stunning images of Jupiter during past perijoves, and the hope is it will have done so again. Thanks to an outreach programme in which NASA invite “citizen scientists” to download raw JunoCam images and process them at their leisure, together with a programme that allows the public to suggest areas the camera might image during each perijove, JunoCam has become extremely popular.

A stunning view of the intricate boundaries between Jupiter's bands of cloud, as captured by JunoCam during the December close pass over the cloud tops in December. The white spot is one of the "pearls" - thought to be a storm - which form bright "strings" in Jupiter's southern hemisphere

A stunning view of the intricate boundaries between Jupiter’s bands of cloud, as captured by JunoCam during the December close pass over the cloud tops in December. The white spot is one of the “pearls” – thought to be a storm – which form bright “strings” in Jupiter’s southern hemisphere

The next close flyby will be on March 27th. It’s not clear yet whether this will be a science pass, or whether the Juno Mission team will risk firing the vehicle’s motor to slow it into the planned 14-day orbit. If they do, then the science suite will likely be powered down to conserve electrical power during the manoeuvre.

But even if Juno doesn’t achieve that final 14-day orbit, its science mission will not be unduly compromised. The craft will be able to meet all of its mission goals even if it remains in the 53.5-day polar orbit it currently occupies.

A major reason for Juno's polar orbit around Jupiter is that it allows the vehicle to pass "between" the most powerful and intense radiation belts emanating from the planet. Credit: NASA

A major reason for Juno’s polar orbit around Jupiter is that it allows the vehicle to pass “between” the most powerful and intense radiation belts emanating from the planet. However, as the mission continues, the tilt of the spacecraft’s orbit relative to the planet means that over time, it will increasingly delve into these more intense radiation belts. Credit: NASA

The Jovian system is a place of intrigue. Not only is Jupiter a potential key to helping us understand the evolution of such gas giant planets, it sits at the centre of a gigantic magnetosphere so vast and powerful, it extends 5 million kilometres (3 million miles) towards the Sun, and reaches out as far as the orbit of Saturn – 651 million kilometres (407 million miles) – in the other direction.

All of Jupiter’s Galilean moons,  Callisto, Ganymede, Europa and Io, orbit within this magnetosphere, “bubble” and are affected by it. However, it is innermost Io which has the greatest interaction, and a proposal has been put forward to have Juno examine the relationship between Io and Jupiter in greater detail.

A false colour enhanced image of a volcanic plume above Io. Credit: NASA

A false colour enhanced image of a volcanic plume above Io. Credit: NASA

With Jupiter on one side, and the other three big moons on the other, Io, roughly 320 km (200 mi) small in diameter than the Moon, is constantly being flexed by the opposing gravitational forces. This flexing physically manifests in the moon being the most volcanically active place in the solar system. At any given time, Io has an estimated 300 active volcanoes belching sulphur, sulphur dioxide gas and fragments of basaltic rock up into the space above itself to interact  with Jupiter’s magnetosphere.

As the material from the eruptions rise from Io, it is bombarded by high-energy electrons withing Jupiter’s magnetsphere.  These ionise the ejected material, forming a vast plasma torus of highly energised (aka radioactive) particles around the Jupiter and straddling Io’s orbit. In addition, Jupiter’s magnetic field also couples Io’s polar atmosphere to the planet’s polar regions, pumping this ionised material through two “pipelines” to the magnetic poles and generating a powerful electric current known as the Io flux tube, which can most visibly be seen (if you are close enough) as Jupiter’s polar aurora.

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Space Sunday: success, loss and safe modes

A colour-enhanced image of Jupiter's south pole, created by "citizen scientist" Alex Mai, as a part of the public Junocam project. using data from Juno's JunoCam instrument. Credit: NASA/JPL / SwRI / MSSS / Alex Mai - see later in this article for an update on the Juno mission

A colour-enhanced image of Jupiter’s south pole, created by “citizen scientist” Alex Mai, as a part of the public JunoCam project. Credit: NASA/JPL / SwRI / MSSS / Alex Mai – see later in this article for an update on the Juno mission

On Wednesday, October 19th, 2016, the European Space Agency (ESA) attempted, for them, a double first: placing a vehicle successfully in orbit around Mars (the Trace Gas Orbiter, or TGO) and landing a vehicle on the planet’s surface (the Schiaparelli demonstrator).

Launched in March 2016, TGO is the second European orbiter mission to Mars, the first being Mars Express, which has been operating around the red planet for 12 years. TGO’s mission is to perform detailed, remote observations of the Martian atmosphere, searching for evidence of gases which may be possible biological importance, such as methane and its degradation products. At the same time, it will to image Mars, and act as a communications for Europe’s planned 2020 Mar rover vehicle.

October 16th, 2016: the Schiaparelli EDM separates from ESA's TGO, en-route for what had been hoped would be a safe landing on Mars. Credit: ESA

October 16th, 2016: the Schiaparelli EDM separates from ESA’s TGO, en-route for what had been hoped would be a safe landing on Mars. Credit: ESA

TGO’s primary mission won’t actually start until late 2017. However, October 19th marked the point at which the vehicle entered its preliminary orbit around Mars.  Orbital insertion was achieved following a 139-minute engine burn which slowed the vehicle sufficiently  to place  it in a highly elliptical, four-day orbit around Mars. Early next year, the spacecraft will begin shifting to its final science orbit, a circular path with an altitude of 400 km (250 mi), ready to start its main science mission.

On Sunday, October 16th, prior to orbital insertion, TGO had bid farewell to the 2-metre diameter Schiaparelli  Entry, Descent and Landing Demonstrator Module (EDM), which it had carried to Mars. The EDM was specifically designed to gather data on entry into, and passage through, the Martian atmosphere and test landing systems in preparation for ESA’s 2020 rover mission landing. 

Schiaparelli's route to the surface of Mars. Credit: ESA

Schiaparelli’s route to the surface of Mars (click for full size). Credit: ESA

Once separated from TGO, Schiaparelli travelled ahead of the orbiter, entering the Martian atmosphere at a speed of 21,000 km/h (13,000 mph; 5.8 km/s / 3.6 mi/s), at 14:42 UT on October 19th. After using the upper reaches of the Martian atmosphere to reduce much of its velocity, Schiaparelli should have proceeded to the surface of Mars using a mix of parachute and propulsive descent, ending with a short drop to the ground, cushioned by a crushable structure designed to deform and absorb the final touchdown impact. Initially, everything appeared to go according to plan. Data confirmed Schiaparelli had successfully entered the Martian atmosphere and dropped low enough for the parachute system to deploy. Then things went awry.

Analysis of the telemetry suggests Schiaparelli prematurely separated from its parachute, entering a period of free fall before the descent motors fired very briefly, at too high an altitude and while the lander was moving too fast. Shortly after this, data was lost. While attempts were made to contact the EDM using ESA’s Mars Express and NASA’s Mars Reconnaissance Orbiter (MRO) it was not until October 20th that Schiaparelli’s fate became clear.

Images taken by MRO  of Schiaparelli’s landing zone revealed a new 15x40m (49x130ft) impact crater, together with a new bright object about 1 kilometre south of it. The crater is thought to be Schiaparelli’s impact point, and the latter the lander’s parachute and aeroshell.

In releasing the NASA images on October 21st, the European Space Agency stated,”Estimates are that Schiaparelli dropped from a height of between 2 and 4 km (1.4-2.4 mi), impacting at a  speed greater than 300 km/h (186 mph). It is also possible that the lander exploded on impact, as its thruster propellant tanks were likely still full.”

Point of impact: on the left, images of Schiaparelli's landing zone taken in May 2016 and on October 20th, 2016, superimposed on one another, the October 20th image clearing showing an impact feature. On the right, an enlarged view of the same two images, showing the impact feature and, south of it, the white canopy of Schiaparelli's parachute. Credit: NASA/JPL / MSSS

Point of impact: on the left, images of Schiaparelli’s landing zone taken in May 2016 and on October 20th, 2016, superimposed on one another. The October 20th image clearly shows an impact feature with a bright object to the south, thought to be Schiaparelli’s parachute canopy. On the right, an enlarged view of the same two images. Credit: NASA/JPL / MSSS

While the lander carried a small suite of science instruments which would have been used to monitor the environment around it for a few days following the landing, the major part of the mission was to gather data atmospheric entry and the use of parachute and propulsive descent capabilities. ESA believe this part of the mission to have been a success, even with minimal data gathered on the propulsive element of the descent.

In the meantime, TGO is currently on a 101,000 km x 3691 km orbit (with respect to the centre of the planet). It is fully functional, and will undertake instrument calibration operations in November, prior to commencing the gentle aerobraking manoeuvres designed to reduce and circularise its orbit around Mars.

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Space Sunday: Jupiter’s poles, signals from space, exploding rockets

Captured at a distance of 78,000 km (48,000 mi) from Jupiter by JunoCam, this image reveals the pale bluish region of Jupiter's north polar region, speckled by hurricane-like cloud formations

Captured at a distance of 78,000 km (48,000 mi) from Jupiter by JunoCam, this image reveals the pale bluish region of Jupiter’s north polar region, speckled by hurricane-like cloud formations. Credit: NASA/JPL / SwRI / MSSS

NASA’s Juno spacecraft has continued to return data and images from its second pass around Jupiter on August 27th, 2016. Images in visible and infra-red light have been received as a part of the data – together with the sound of Jupiter’s “voice”.

Of particular interest are the images of Jupiter’s north pole – which has never been seen by human eyes, and is revealed as being vastly different to the rest of the planet, together with detailed images of the planet’s south pole, only previously briefly seen by the Cassini mission in 2008, whilst en route to Saturn.

“First glimpse of Jupiter’s north pole, and it looks like nothing we have seen or imagined before,” said the Juno mission’s principal investigator Scott Bolton on the release of the most recently received images and data on Friday, September 2nd.

An enhanced view of the north polar hurricane-like clouds images by Juno on August 27th, 2016

An enhanced view of the north polar hurricane-like clouds images by Juno on August 27th, 2016, together with the blue tingle of the polar atmosphere. Credit: NASA/JPL / SwRI / MSSS

“It’s bluer in colour 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 recognisable as Jupiter. We’re seeing signs that the clouds have shadows, possibly indicating that the clouds are at a higher altitude than other features.”

All of Juno’s science instruments were active during the flyby,gathering some 6 Mb of data, images and sounds, which was transmitted back to Earth over a period of a day and a half once the space vehicle had moved away from Jupiter once more. Among this data were images from the Italian-built Jovian Infra-red Auroral Mapper (JIRAM), which returned the first ever close-up infra-red images of Jupiter’s massive aurora.

A mosaic of three infra-red images of Jupiter's southern aurora taken some 4 hours after the closest point of the flyby. The images were captured by the Jovian Infra-red Auroral Mapper (JIRAM) camera aboard Juno at wavelengths ranging from 3.3 to 3.6 microns -- the wavelengths of light emitted by excited hydrogen ions

A mosaic of three infra-red images of Jupiter’s southern aurora taken some 4 hours after the closest point of the flyby. The images were captured by the Jovian Infra-red Auroral Mapper (JIRAM) camera aboard Juno
at wavelengths ranging from 3.3 to 3.6 microns — the wavelengths of light emitted by excited hydrogen ions. Credit: NASA/JPL / SwRI / IAPS

“JIRAM is getting under Jupiter’s skin, giving us our first infra-red close-ups of the planet,” said Alberto Adriani, JIRAM co-investigator from Istituto di Astrofisica e Planetologia Spaziali, Rome. “These views of Jupiter’s north and south poles are revealing warm and hot spots that have never been seen before.

“No other instruments, both from Earth or space, have been able to see the southern aurora,” he continued. “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.”

Juno doesn’t only have eyes, it has ears as well. We’ve known for a long time that Jupiter can be quite “vocal”, and the flyby allowed Juno’s Radio/Plasma Wave Experiment (WAVE) to capture the sound of the planet’s aurorae.

“Jupiter is talking to us in a way only gas-giant worlds can,” said Bill Kurth, co-investigator for WAVE. “We 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.”

Juno is now heading back away from Jupiter on the second of its “long” orbits of the planet. On October 19th, the spacecraft will once again skim over Jupiter’s cloud tops, where it will perform a further braking manoeuvre to reduce its orbital period around the planet to just 14 days.

Did ET Call Us? Mostly Likely Not

The end of August saw  various media outlets a-buzz with news about Russian scientists having detected a “strong” radio signal from deep space, with muttering and speculations about aliens, despite cautionary notes from assorted space-related outlets and organisations.

The signal was actually detected in May 2015 by the RATAN-600 radio telescope in Zelenchukskaya, south-western Russia. At the time, the telescope was conducting a survey of astronomical objects in the framework of the SETI (Search for Extraterrestrial Intelligence) programme. It seemed to come from the general direction of the star HD 164595, a star around 95 light years away which is very similar to our own Sun but about 1.5 billion years older, and known to have at least one planet – a gas giant roughly the mass of Neptune – orbiting it.

News about it reached a wider audience in August when a member of the team behind the survey decided to e-mail data on it to colleagues asking for thoughts on what it might be, and suggesting the region of the sky containing HD 164595 should be monitored for further indications of the signal and possible causes.

The RATAN-600 radio telescope. Credit: Russian Academy of Sciences

The RATAN-600 radio telescope. Credit: Russian Academy of Sciences

This request was picked up by science and technology writer Paul Gilster, who blogged about it on his website Centauri Dreams.  While Gilster clearly stated there was no evidence of the signal being the work of an extra-terrestrial civilisation, he did couch his post in terms of the power requirements and possible technological status of such a civilisation were the signal to prove to be artificial in nature.

The information was also received by the SETI Institute in California. Their senior astronomer, Seth Shostak, estimated that if transmitting  in all directions, the signal would require energy on the order of 10^20 watts – or more energy than the Earth receives from the Sun – making the originating species a Type II civilisation on the Kardashev scale. If directed solely towards Earth,  Shostak estimated the energy requirement would “only” be around 10^13 watts – roughly equivalent to all of the energy used by humanity here on Earth, putting the aliens at a Type I civilisation on the Kardashev scale – that is, equal to or slightly more advanced than we are.

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Space Sunday: exoplanets, dark matter, rovers and recoveries

An artist's impression of Proxima b with Proxima Centauri low on the horizon. The double star above and to the right of it is Alpha Centauri A and B. Credit: ESO

An artist’s impression of Proxima b with Proxima Centauri low on the horizon. The double star above and to the right of it is Alpha Centauri A and B. Credit: ESO

On August 15th, I wrote about rumours that an “Earth-like” planet has been found orbiting our nearest stellar neighbour, Proxima Centauri, 4.25 light years away from our own Sun. The news was first leaked by the German weekly magazine, Der Spiegel, which indicated the discovery had been made by a team at the European Southern Observatory’s (ESO)  La Silla facility – although ESO refused to comment at the time.

However, during a press conference held on August 24th, ESO did confirm the detection of a rocky planet orbiting Proxima Centauri. Dubbed Proxima b, the planet lies within the so-called “Goldilocks” habitable zone around its parent star – the orbit in which conditions are “just right” for the planet to harbour liquid water and offer the kind of conditions in which life might arise.

Comparing Proxima b with Earth. Credit: Space.com

Comparing Proxima b with Earth. Credit: Space.com

The ESO data reveals that Proxima b is orbits its parent star at a distance of roughly 7.5 million km (4.7 million miles), at the edge of the habitable zone, and does so every 11.2 terrestrial days and is about 1.3 times as massive as the Earth. The discovery came about by comparing multiple observations of the star over extended periods using two instruments at La Silla to look for signs of the star “wobbling” in its own spin as a result of planetary gravitational influences. Once identified, ESO called on other observatories around the world to carry out similar observations / comparisons to confirm their findings.

Although the planet lies within the “Goldilocks zone”, just how habitable is it likely to be is still open to question. Stars like Proxima Centauri, which is roughly one-seventh the diameter of our Sun, or just 1.5 times bigger than Jupiter, are volatile in nature, all activity within them entirely convective in nature, giving rise to massive stellar flares. As Proxima-B orbits so close to the star, it is entirely possible that over the aeons, such violent outbursts from Proxima Centauri have stripped away the planet’s atmosphere.

Proxima Cantauri compared with other stellar bodies - and Jupiter (Credit: Space.com)

Proxima Cantauri compared with other stellar bodies – and Jupiter. Credit: Space.com

In addition, the preliminary data from ESO suggests the planet is either tidally locked to Proxima Centauri, or may have a 3:2 orbital resonance (i.e. three rotations for every two orbits) – either of which could make it an inhospitable place for life to gain a toe-hold. The first would leave one side in perpetual daylight and the other in perpetual night, while the second would limit any liquid water on the surface to the tropical zones.

Nevertheless, the discovery of another world in one part of our stellar backyard does raise the question of what NASA’s upcoming TESS mission might find when it starts searching the hundreds of nearby stars for evidence of exoplanets in 2018.

Juno’s Second Pass Over Jupiter

NASA’s Juno space craft made a second successful close sweep over the cloud-tops of Jupiter on Saturday, August 27th to complete its first full orbit around the planet. Speeding over the planet at a velocity of 208,000 km/h (130,000 mph) relative to Jupiter, Juno passed just 2,400 km (2,600 miles) above the cloud tops before heading back out into space, where it will again slowly decelerate under the influence of Jupiter’s immense gravity over the next 27 days, before it once again swing back towards the gas giant.

“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, as telemetry on the flyby started being received on Earth some 48 mins after the flyby, which occurred at 13:44 UTC.

A twin view of Jupiter captured by Juno on August 23rd, when the spacecraft was some 4.4 million km (2.8 million miles) from the gas giant and approaching Jupiter to complete its first full orbit. On the left is a colour image from JunoCam, on the right an infra-red image Credit: NASA/JPL-Caltech/SwRI/MSSS

A twin view of Jupiter captured by Juno on August 23rd, when the spacecraft was some 4.4 million km (2.8 million miles) from the gas giant and approaching Jupiter to complete its first full orbit. On the left is a colour image from JunoCam, on the right an infra-red image. Credit: NASA/JPL / SwRI / MSSS

All of Juno’s science suite was in operation during the passage over Jupiter’s clouds. However, due to speed at which the gathered data can be returned to Earth, and given it cannot all be relayed in one go or necessarily continuously, it will be a week or more before everything has been transmitted back to Earth. Nevertheless the science team are already excited by the flyby.

“We are getting some intriguing early data returns as we speak,” Scott Bolton, principal investigator of Juno from the Southwest Research Institute, stated. Some of that data included initial images of Jupiter captured as Juno swept towards the planet during the run-up to periapsis. “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,” Bolton added.

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