Cassini began the final phase of its mission this week, executing the first of five ultra-close passes of the gas giant. Photo / 123RF
Cassini began the final phase of its mission this week, executing the first of five ultra-close passes of the gas giant. Photo / 123RF
By Cheyenne Macdonald
A stunning new view of Saturn has revealed waves of clouds swirling above the planet, like "strokes from a cosmic brush".
The image, captured by the Cassini spacecraft from roughly 1.2 million km above the surface, shows the turbulent essence of Saturn's clouds, which move as bands in different speeds and directions.
Cassini began the final phase of its mission this week, executing the first of five ultra-close passes of the gas giant yesterday afternoon, according to Daily Mail.
The image shows the turbulent essence of Saturn's clouds, which move as bands in different speeds and directions. Photo / Nasa
"Saturn's upper atmosphere generates the faint haze seen along the limb of the planet in this image."
Now, Cassini is much further along in its journey - and, less than a month from now, its mission will come to a dramatic end.
Earlier this week, the spacecraft sent back stunning images of Saturn's largest moon, Titan, as it prepares to end its 20-year mission.
Titan's surface can be seen in incredible detail, as well as the moon's ever-changing atmosphere.
The images come as Cassini begins the final phase of its journey around Saturn.
On Monday, at 00.22 EST (Tuesday, 16.20 NZT) the probe executed the first of five ultra-close passes of the gas giant, brushing the top of its atmosphere.
Data from the manoeuvre is expected to be received back on Earth tomorrow, and Nasa hopes it will provide new information of the chemical composition of Saturn.
At the end of last week, Nasa revealed the images taken by Cassini as it pierced through hydrocarbon haze that surrounds Titan and capture the images of the moon.
In addition to Titan's surface, the images show the moon's ever-changing atmosphere, chronicling the appearance and movement of hazes and clouds over the years.
A large, bright and feathery band of summer clouds can be seen arcing across high northern latitudes in the image on the right.
The stunning views were captured at a distance of 986,000km from Titan.
Just days into its Grand Finale mission phase, Nasa's Cassini spacecraft has sent back stunning images of Saturn's largest moon, Titan. Photo / Nasa
Over the course of its 13-year orbit around Saturn, Cassini has made 127 close flybys of Titan, with many more-distant observations.
While early images of Titan taken by Cassini were spotty, every encounter has built upon the previous one.
And over the course of the entire mission, Cassini's radar investigation imaged approximately 67 per cent of Titan's surface.
Views from Cassini have slowly added details, building up a more complete picture of Titan.
Steve Wall, deputy lead of Cassini's radar team at Nasa's Jet Propulsion Laboratory, said: "Now that we've completed Cassini's investigation of Titan, we have enough detail to really see what Titan is like as a world, globally."
Scientists now have enough data to understand the distribution of Titan's surface features and the behaviour of its atmosphere over time.
During its latest close brush with Titan as it heads into its Grand Finale, Cassini imaged a long area of the surface that included terrain seen on the very first Titan flyby in 2004.
Wall said: "It's pretty remarkable that we ended up close to where we started.
"The difference is how richly our understanding has grown, and how the questions we're asking about Titan have evolved."
In today's first pass, the researchers expect Cassini's thrusters to operate between 10 and 60 per cent of their capability.
If they have to work harder, the team will have to increase the altitude of the next orbits in what's known as a "pop-up manoeuvre".
If the pop-up is deemed necessary, the thrusters will raise the altitude of closest approach by about 193km.
If not, and the atmosphere is less dense than expected, the team may use the pop-down and instead lower the closest approach of the last two orbits by about 193km.
This would allow Cassini's instruments to gather unprecedented data near the cloud tops.
"As it makes these five dips into Saturn, followed by its final plunge, Cassini will become the first Saturn atmospheric probe,' said Linda Spilker, Cassini project scientist at JPL.
"It's long been a goal in planetary exploration to send a dedicated probe into the atmosphere of Saturn, and we're laying the groundwork for future exploration with this first foray."
The ion and neutral mass spectrometer (INMS) will investigate the atmosphere, while other instruments will capture high-resolution observations of Saturn's auroras, temperature, and the vortexes at the planet's poles, according to Nasa.
The craft's radar will look deep into the atmosphere to see features as small as 25km wide.
This is about 100 times smaller than it could previously achieve.
The Cassini-Huygens spacecraft in orbit around Saturn. Photo / Getty Images
Then, on September 11, Cassini will have a gravitational pop-down as it encounters Titan, slowing its orbit around Saturn and bending its path to send the craft toward its plunge.
On September 15, the craft will begin its mission-ending decent.
During this time, seven instruments will be turned on and monitoring the environment in real time as Cassini plummets to an altitude where density is roughly twice what it experienced during the final five orbits.
"Once Cassini reaches this point, its thrusters will no longer be able to work against the push of Saturn's atmosphere to keep the spacecraft's antenna pointed toward Earth, and contact will permanently be lost,' Nasa explains.
"The spacecraft will break up like a meteor moments later, ending its long and rewarding journey."
