OrbitalHub

ESA dixit:

“The JUpiter ICy moons Explorer (JUICE) is the first L-class mission within ESA’s Cosmic Vision programme. It aims at a comprehensive exploration of the Jovian system with particular emphasis on Jupiter, its environment, and Galilean moons Ganymede, Europa and Callisto by investigating them as planetary bodies and potential habitats.

Scheduled for launch in 2022, with arrival in the Jovian system in 2029, JUICE will spend three-and-a-half years examining the giant planet’s turbulent atmosphere, enormous magnetosphere, its set of tenuous dark rings and its satellites. It will study the large icy moons Ganymede, Europa and Callisto, which are thought to have oceans of liquid water beneath their icy crusts – perhaps even harbouring habitable environments. The mission will culminate in a dedicated, eight-month tour around Ganymede, the first time any moon beyond our own has been orbited by a spacecraft.

JUICE will be equipped with 10 state-of-the-art instruments, including cameras, an ice-penetrating radar, an altimeter, radio-science experiments, and sensors to monitor the magnetic fields and charged particles in the Jovian system. In order to ensure it can address these goals in the challenging Jovian environment, the spacecraft’s design has to meet stringent requirements. An important milestone was reached earlier this month, when the preliminary design of JUICE and its interfaces with the scientific instruments and the ground stations were fixed, which will now allow a prototype spacecraft to be built for rigorous testing. The review also confirmed that the 5.3 tonne spacecraft will be compatible with its Ariane 5 launcher.

Operating in the outer Solar System, far from the Sun, means that JUICE needs a large solar array: two wings of five panels each are foreseen, which will cover a total surface area of nearly 100 m², capable of providing 820 W at Jupiter by the end of the mission. After launch, JUICE will make five gravity-assist flybys in total: one each at Mars and Venus, and three at Earth, to set it on course for Jupiter. Its solar panels will have to cope with a range of temperatures such that when it is flying closer to the Sun during the Venus flyby, the solar wings will be tilted to avoid excessive temperatures damaging the solar cells.

The spacecraft’s main engine will be used to enter orbit around the giant planet, and later around Jupiter’s largest moon, Ganymede. As such, the engine design has also been critically reviewed at this stage. Special measures will allow JUICE to cope with the extremely harsh radiation that it must endure for several years around Jupiter. This means careful selection of components and materials, as well as radiation shielding. One particularly important topic is JUICE’s electromagnetic ‘cleanliness’. Because a key goal is to monitor the magnetic fields and charged particles at Jupiter, it is imperative that any electromagnetic fields generated by the spacecraft itself do not interfere with the sensitive scientific measurements. This will be achieved by the careful design of the solar array electrical architecture, the power distribution unit, and the reaction wheels – a type of flywheel that stabilizes the attitude.

[…]JUICE will meet strict planetary protection guidelines, because it is imperative to minimize the risk that the potentially habitable ocean moons, particularly Europa, might be contaminated by viruses, bacteria or spores carried by the spacecraft from Earth. Therefore, mission plans ensure that JUICE will not crash into Europa, on a timescale of hundreds of years.”

Video credit: ESA

NASA dixit:

“January 14, 2005. This is an artist’s interpretation of the area surrounding the Huygens landing site, based on images and data returned.”

“After almost 20 years in space, NASA’s Cassini spacecraft begins the final chapter of its remarkable story of exploration: its Grand Finale. Between April and September 2017, Cassini will undertake a daring set of orbits that is, in many ways, like a whole new mission. Following a final close flyby of Saturn’s moon Titan, Cassini will leap over the planet’s icy rings and begin a series of 22 weekly dives between the planet and the rings.

No other mission has ever explored this unique region. What we learn from these final orbits will help to improve our understanding of how giant planets – and planetary systems everywhere – form and evolve.

On the final orbit, Cassini will plunge into Saturn’s atmosphere, sending back new and unique science to the very end. After losing contact with Earth, the spacecraft will burn up like a meteor, becoming part of the planet itself.

Cassini’s Grand Finale is about so much more than the spacecraft’s final dive into Saturn. That dramatic event is the capstone of six months of daring exploration and scientific discovery. (And those six months are the thrilling final chapter in a historic 20-year journey.)”

Image credit: NASA

NASA dixit:

“January 14, 2005. Image collected during the 147-minute plunge through Titan’s thick orange-brown atmosphere to a soft sandy riverbed by the European Space Agency’s Huygens Descent Imager/Spectral Radiometer. In 4 minutes and 40 seconds, the movie shows what the probe ‘saw’ within the few hours of the descent and the landing. On approach, Titan appeared as just a little disk in the sky among the stars, but after landing, the probe’s camera resolved little grains of sand millions of times smaller than Titan.

At first, the Huygens camera just saw fog over the distant surface. The fog started to clear only at about 60 kilometers (37 miles) altitude, making it possible to resolve surface features as large as 100 meters (328 feet). Only after landing could the probe’s camera resolve the little grains of sand. The movie provides a glimpse of such a huge change of scale.”

“After almost 20 years in space, NASA’s Cassini spacecraft begins the final chapter of its remarkable story of exploration: its Grand Finale. Between April and September 2017, Cassini will undertake a daring set of orbits that is, in many ways, like a whole new mission. Following a final close flyby of Saturn’s moon Titan, Cassini will leap over the planet’s icy rings and begin a series of 22 weekly dives between the planet and the rings.

No other mission has ever explored this unique region. What we learn from these final orbits will help to improve our understanding of how giant planets – and planetary systems everywhere – form and evolve.

On the final orbit, Cassini will plunge into Saturn’s atmosphere, sending back new and unique science to the very end. After losing contact with Earth, the spacecraft will burn up like a meteor, becoming part of the planet itself.

Cassini’s Grand Finale is about so much more than the spacecraft’s final dive into Saturn. That dramatic event is the capstone of six months of daring exploration and scientific discovery. (And those six months are the thrilling final chapter in a historic 20-year journey.)”

Image credit: NASA

NASA dixit:

“As NASA’s Cassini spacecraft made its first-ever dive through the gap between Saturn and its rings on April 26, 2017, one of its imaging cameras took a series of rapid-fire images that were used to make this movie sequence. The video begins with a view of the vortex at Saturn’s north pole, then heads past the outer boundary of the planet’s hexagon-shaped jet stream and continues further southward.”

Video credit: NASA Jet Propulsion Laboratory

NASA dixit:

“December 3, 2000. The solar system’s largest moon, Ganymede, is captured here alongside the planet Jupiter in a color picture taken by NASA’s Cassini spacecraft. Ganymede is larger than the planets Mercury and Pluto and Saturn’s largest moon, Titan. Both Ganymede and Titan have greater surface area than the entire Eurasian continent on our planet. Cassini was 26.5 million kilometers (16.5 million miles) from Ganymede when this image was taken. The smallest visible features are about 160 kilometers (about 100 miles) across.

The bright area near the south (bottom) of Ganymede is Osiris, a large, relatively new crater surrounded by bright icy material ejected by the impact, which created it. Elsewhere, Ganymede displays dark terrains that NASA’s Voyager and Galileo spacecraft have shown to be old and heavily cratered. The brighter terrains are younger and laced by grooves. Various kinds of grooved terrains have been seen on many icy moons in the solar system. These are believed to be the surface expressions of warm, pristine, water-rich materials that moved to the surface and froze.

Ganymede has proven to be a fascinating world, the only moon known to have a magnetosphere, or magnetic environment, produced by a convecting metal core. The interaction of Ganymede’s and Jupiter’s magnetospheres may produce dazzling variations in the auroral glows in Ganymede’s tenuous atmosphere of oxygen.”

“After almost 20 years in space, NASA’s Cassini spacecraft begins the final chapter of its remarkable story of exploration: its Grand Finale. Between April and September 2017, Cassini will undertake a daring set of orbits that is, in many ways, like a whole new mission. Following a final close flyby of Saturn’s moon Titan, Cassini will leap over the planet’s icy rings and begin a series of 22 weekly dives between the planet and the rings.

No other mission has ever explored this unique region. What we learn from these final orbits will help to improve our understanding of how giant planets – and planetary systems everywhere – form and evolve.

On the final orbit, Cassini will plunge into Saturn’s atmosphere, sending back new and unique science to the very end. After losing contact with Earth, the spacecraft will burn up like a meteor, becoming part of the planet itself.

Cassini’s Grand Finale is about so much more than the spacecraft’s final dive into Saturn. That dramatic event is the capstone of six months of daring exploration and scientific discovery. (And those six months are the thrilling final chapter in a historic 20-year journey.)”

Image credit: NASA

NASA dixit:

“On January 14, 2005, ESA’s Huygens probe made its descent to the surface of Saturn’s hazy moon, Titan. Carried to Saturn by NASA’s Cassini spacecraft, Huygens made the most distant landing ever on another world, and the only landing on a body in the outer solar system. This video uses actual images taken by the probe during its two-and-a-half hour fall under its parachutes.

Huygens was a signature achievement of the international Cassini-Huygens mission, which will conclude on September 15, 2017, when Cassini plunges into Saturn’s atmosphere.”

Video credit: NASA Jet Propulsion Laboratory