The night of the 16th of September 2017 saw the end of a 13-year long mission for the Cassini-Huygens spacecraft end. With the final transmission received at 9:54pm AEST by the Canberra Deep Space Communication Complex, the space craft was no more as it burnt up within Saturn’s atmosphere.
Originally slated to end in 2008, the extended mission lifetime of the Cassini spacecraft has seen our knowledge of about Saturn and its moons grow substantially. Our only knowledge about the outer planets was from Voyager 1 and 2. Cassini was the first spacecraft to orbit Saturn, gathering information about the planets itself but also the Saturn’s moons. However, scenes like this make you wonder why the end was so full of emotions.
The beginning of life off world?
The Cassini mission has made several important discoveries about the gas giant and the moons. The most exciting find is the presence of liquid water on the moons, Titan and Enceladus. Enceladus is a water world (no, not like the 1995 film); a global, liquid water world with salts and simple organic molecules and likely to have hydrothermal vents on the seafloor. The presence of water was confirmed when a flyby flew through a plume of an ice volcano. The water world might be the location for a human colony capable of supporting life.
Huygens on Titan
The Cassini mission included the Huygens probe, named after Christiaan Huygens who first discovered Titan. The Huygens probe was the first probe to land on a surface in the outer solar system. The probe gathered data on Titan’s atmosphere during its two-hour descent to the surface and captured pictures of the cold surface. Scans show a mixture of gases comprising of carbon, nitrogen, methane and ethane. The source of the methane is unknown but it is believed that methane and ethane rain from the clouds in Titan’s atmosphere.
Lord of the Rings
The only observations about the gas giant was only through a few flybys and from Earth. Saturn dwarfs the Earth yet the core is slightly smaller than Earth with the rest of the volume filled by a never-ending storm of gas. This storm has some interesting effects near the poles of the planet. The storms at the north pole has the ‘wind’ going around in a hexagon. A perfect hexagon of gigantic proportions at over 30, 000 kilometres and wind speeds of 322 kilometre per hour. First spotted by Voyager in 1980, the hexagon remains to baffle scientists.
For the Future?
The Cassini probe has given so much for scientists. The findings have boosted our understanding of the gas giant, the rings and the moons. It has found evidence for liquid water on the moon Enceladus giving a possible location for human colonisation. The end of the mission does not mean the end of scientific pursuits to further study the planet. The rich scientific and engineering legacy has seen a 2020 proposed launch for the Titan Saturn System Mission for a more in-depth exploration of Saturn, Titan and Enceldaus.