Illustration showing NASA’s Cassini spacecraft above Saturn’s northern hemisphere, prior to one of its 22 grand finale dives. Image: NASA/JPL-Caltech
NASA’s Cassini spacecraft is set to smash into Saturn after nearly two decades, but the images it captured will live on for years to come.
There will be quite a few emotional NASA and European Space Agency (ESA) employees this week as they count down the hours until the Cassini spacecraft collides with Saturn, bringing its decades-long mission to a close.
Launched in October 1997, the spacecraft remains one of the most ambitious space missions ever, exploring Saturn in unprecedented detail as well as landing the probe Huygens on Saturn’s moon, Titan.
It took seven years for the spacecraft to reach the outer region of our solar system and enter Saturn’s orbit, but not before it made some flybys past Earth, Venus and Jupiter.
Among its original objectives were to create a detailed 3D image of Saturn’s rings to understand their structure and behaviour, as well as the planet’s magnetosphere and nature of its moons, including Phoebe and Enceladus.
While Cassini’s instruments got into action once it reached Saturn’s atmosphere in 2004, much of the early excitement was felt for its partner probe, Huygens, which descended to Titan in early 2005.
Even today, after the scientific achievement that was Rosetta’s Philae lander touching down on a comet for the first time, Huygens remains the only probe to successfully land on another body in the outer reaches of our solar system.
While it transmitted data for just 90 minutes, Huygens showed that Titan had a hazy, thick atmosphere. It resembled the Earth in many ways, with evidence that a liquid – possibly methane – had flowed on the surface, causing erosion.
A fitting end
After Cassini completed its initial mission in 2008, NASA gave the go-ahead to extend it for a further two years, doing so again in 2010 as part of the Cassini Solstice Mission.
In 2016, realising the limited lifespan of its fuel supply, NASA decided that it should be given a grand finale of a mission to climb high above Saturn’s poles, before diving between the planet’s uppermost atmosphere and its innermost ring 22 times.
But now, the craft is set to go out in a blaze of glory after nearly 20 years of unbridled success, by crashing into Saturn’s surface, scattering the inanimate object’s remains across the planet it has gotten to know in intimate detail.
Here are just 10 images it has taken over the years that have left many breathless.
Saturn’s shadow on the rings grows shorter as the planet’s season advances toward northern summer, thanks to its permanent tilt as it orbits the sun. Image: NASA/JPL-Caltech/Space Science Institute
A false-colour view of Saturn’s clouds. Image: NASA/JPL-Caltech/Space Science Institute/Kevin M Gill
Another false-colour image of the spinning vortex of Saturn’s north polar storm resembling a deep red rose of giant proportions. Image: NASA/JPL-Caltech/Space Science Institute
Cassini captured this view of Saturn’s north pole on 26 April 2017 – the day it began its grand finale as it approached the planet for its first daring dive through the gap between the planet and its rings. Image: NASA/JPL-Caltech/Space Science Institute
Four photos taken by the Huygens probe at four different altitudes during its descent on the surface of Titan in 2005. They remain the only photos we have of the surface of one of the outer planets in the solar system. Image: ESA/NASA/JPL/University of Arizona
A view of Titan in front of Saturn’s northern, sunlit side of the rings from just above the ring plane. Image: NASA/JPL-Caltech/SSI
Pan, Saturn’s ravioli-like moon, as seen by Cassini. It remains one of the most peculiar-shaped satellites in the solar system. Image: NASA/JPL-Caltech/Space Science Institute
Scientists expected the north polar region of Enceladus to be heavily cratered, based on low-resolution images from the Voyager mission, but high-resolution Cassini images show a landscape of stark contrasts. Image: NASA/JPL-Caltech/Space Science Institute
Cassini scientists think that Hyperion’s unusual appearance can be attributed to the fact that it has an unusually low density for such a large object, giving it weak surface gravity and high porosity. Image: NASA/JPL/Space Science Institute
As it dove through the gap between the planet and its rings last April, Cassini came within about 3,000km of Saturn’s cloud tops, and within about 300km of the innermost visible edge of the rings, bringing us the closest ever images of the planet. Image: NASA/JPL-Caltech/Space Science Institute
