NASA’s Cassini mission has sent back the first views from its new orbit around Saturn.
In November, Cassini spacecraft began a new phase of its mission – one that involves making a series of daredevil maneuvers over the next nine months.
The phase will end with Cassini being destroyed in the atmosphere of a planet it has been studying for 12 years.
The new photos show the hexagon-shaped storm in Saturn’s northern hemisphere.
Cassini began what are known as its ring-grazing orbits on November 30. Each of these week-long orbits – 20 in all – lifts the spacecraft high above Saturn’s northern hemisphere before sending it hurtling past the outer edges of the planet’s main rings.
Image source Wikimedia
NASA said that it would release images from future passes that included some of the closest-ever views of the outer rings and small moons that orbit there.
Head of Cassini’s imaging team Carolyn Porco said: “This is it, the beginning of the end of our historic exploration of Saturn.
“Let these images – and those to come – remind you that we’ve lived a bold and daring adventure around the Solar System’s most magnificent planet.”
The destructive ending being planned for Cassini is a result of the spacecraft having nearly exhausted its fuel.
However, NASA is also concerned about the small, yet important possibility that the probe will crash into one of Saturn’s moons at some point in the future.
Given that some of these bodies, such as Enceladus, are potential targets in the search for extra-terrestrial life, it has the potential to contaminate these bodies with terrestrial microbes borne on Cassini.
Starting from April 2017, Cassini will begin its grand finale, in which it will make the first of 22 dives through the 2,400km gap between the planet and its innermost ring.
Cassini will make its final plunge into the atmosphere of Saturn on September 15, 2017.
NASA’s Cassini probe has captured striking images from flying by three moons of Saturn, including new pictures of Enceladus’s gushing geysers.
Cassini made its lowest pass yet over the south pole of Enceladus, at at an altitude of 74 km (46 miles).
This allowed it to “taste” the jets of water vapor and ice that the moon spews forth into space.
Cassini probe also made relatively close flypasts of two other Saturnian satellites: Dione and Janus.
The observations were made over 27 and 28 March.
The encounter was primarily designed for Cassini’s ion and neutral mass spectrometer instrument, which sampled the composition of Enceladus’s south polar plume.
Other instruments, including the Cassini plasma spectrometer and composite infrared spectrometer, also took measurements.
Cassini probe has captured striking images of Enceladus's gushing geysers
Before the closest approach to Enceladus, Cassini’s onboard cameras captured images of the geysers, which contain organic compounds along with the ice and vapor.
The jets erupt from cracks, or hot fissures, at the south pole known as “tiger stripes”.
Several lines of evidence suggest the jets are fed by a liquid water ocean beneath Enceladus’ outer icy shell.
Scientists have previously detected salts in these jets, which suggests the ocean is probably in contact with the moon’s rocky core.
“Cassini has flown several times now through this spray and has tasted it. And we have found that aside from water and organic material, there is salt in the icy particles. The salinity is the same as that of Earth’s oceans,” said Dr. Carolyn Porco, head of the imaging team on Cassini.
As the spacecraft passed Enceladus, the cameras made a nine-frame mosaic of the surface of Enceladus’s leading hemisphere.
Cassini then flew by the small moon Janus with a closest approach distance of 44,000 km. The planet was in the background in some of these views.
On 28 March, the spacecraft passed Dione at roughly the same distance and captured, among other observations, a nine-frame mosaic depicting the side of the moon that faces away from Saturn.
Scientists recently presented evidence that Dione has features resembling tiger stripes and a cryovolcano, which erupts water-ammonia or methane instead of molten rock.
It is unclear whether there is current geological activity at Dione, but, if so, it is almost certainly at a lower level than on Enceladus.
The discovery that Enceladus probably harbors an ocean in contact with the rocky core makes this moon an even more important target in the search for life elsewhere in the Solar System. The rocks could furnish the ocean with the chemical ingredients thought essential for life.
“The kind of ecologies Enceladus might harbor could be like those deep within our own planet,” Dr. Carolyn Porco said in an interview with NASA’s science website.
The habitable zone on Enceladus might be comparatively easy to access by future robotic space missions. Dr. Carolyn Porco added: “It’s erupting out into space where we can sample it. It sounds crazy but it could be snowing microbes on the surface of this little world.
“In the end, it’s the most promising place I know of for an astrobiology search. We don’t even need to go scratching around on the surface. We can fly through the plume and sample it. Or we can land on the surface, look up and stick our tongues out.”
The source of Enceladus’s heat appears to be Saturn itself. The moon moves around Saturn in a distorted, oval-shaped orbit rather than a circular one.
This causes it to be pulled and squeezed by Saturn’s gravity, inducing the heat that enables geological activity on the icy moon.
NASA’s Cassini probe will make today its lowest pass yet over the south pole of Enceladus, an active moon of Saturn which may harbor a liquid water ocean.
The flyby, at an altitude of 74 km (46 miles), will allow Cassini to “taste” the jets of ice and water vapor that gush from the moon’s polar region.
Several lines of evidence suggest these jets are fed by a liquid water ocean beneath Enceladus’ outer icy shell.
The probe’s closest approach will take place at 19:30 GMT on Tuesday.
The scientists will use Cassini’s Ion and Neutral Mass Spectrometer instrument to learn more about the composition, density and variability of the plumes from Enceladus.
Scientists previously detected salts in these jets, which suggested the sub-surface liquid water ocean was probably in contact with Enceladus’ rocky core.
This makes Enceladus an even more important target in the search for life elsewhere in the Solar System, as rocks could furnish the ocean with the chemical ingredients thought essential for life.
Cassini probe will make today its lowest pass yet over the south pole of Enceladus, an active moon of Saturn which may harbor a liquid water ocean
The plumes erupt from fissures at the south pole known as “tiger stripes”.
Last week, scientists presented evidence of a connection between the jet activity on Enceladus and the way Saturn’s gravity stretches and stresses the fissures.
The results were outlined by Terry Hurford, from NASA’s Jet Propulsion Laboratory (JPL), at the Lunar and Planetary Science Conference (LPSC) in The Woodlands, Texas.
However, about 35% of the observations could not be explained by tension in the jets’ source regions.
Enceladus moves around Saturn in a distorted, oval-shaped orbit rather than a circular one. This causes the moon to be pulled and squeezed by Saturn’s gravity, inducing the heat that enables geological activity on the icy moon.
Cassini’s closest approach to any part of Enceladus occurred in October 2008, when it flew within about 25 km (16 miles) of the surface.
A flyby in October 2015 will bring Cassini about 25 km closer to the moon.