NASA’s Cassini spacecraft has now officially entered the last phase of its mission – the “Grand Finale,” with the last-ever close flyby of Titan and the first of 22 final orbits which will take the spacecraft closer to Saturn than ever before, passing between the inner rings and the planet itself. Cassini has today just completed the first of these passes (with results pending for a few hours as of this writing), which will culminate on Sept. 15 with the spacecraft plunging into Saturn’s atmosphere to meet its fiery end. It will be a sad but incredible ending to an incredible mission.
This week marks another important milestone in the Cassini mission at Saturn – as of today, the spacecraft is conducting the last Ring-Grazing Orbit of its mission as it prepares for the Grand Finale, which will culminate in the death of the probe on Sept. 15. On April 21, Cassini will do its very last close flyby of Saturn’s largest moon Titan. Speaking of Titan, Cassini has also apparently solved a perplexing mystery; the unusual “magic island” formations seen in one of the moon’s methane/ethane seas are now thought to be caused by nitrogen bubbles fizzing periodically on the sea’s surface.
Some great new views from the Cassini spacecraft of Saturn’s tiny moon Atlas were released today. Atlas is similar to another Saturnian “ravioli” or “flying saucer” moon, Pan – a central roughly spherical or oblate body with an unusual broad equatorial ridge. Like Pan, the ridge is thought to have formed from material coming from Saturn’s rings, and also like Pan, the ridge on Atlas appears very smooth, but is significantly larger. Atlas orbits just outside the outer edge of Saturn’s A ring and is very small, only about 15 kilometres (9.4 miles) across, but still larger than Pan.
NASA’s Cassini mission to Saturn has been one of the most successful and awe-inspiring ever, studying the giant ringed planet and its many moons since 2004. But now, scientists are preparing for what everyone knew would come eventually – the end of Cassini’s excursions throughout the Saturn system. Yesterday, NASA held a news conference to celebrate what Cassini has accomplished and outline what will happen during the next few months, culminating with the end of the mission in September.
Saturn’s moon Titan is the only other body in the Solar System besides Earth known to have liquids on its surface. In Titan’s case, they are rivers, lakes and seas of liquid hydrocarbons (methane/ethane) instead of water. There is even methane/ethane rain, which further mimics Earth’s hydrological cycle. For the most part, the lakes and seas are fairly smooth, with only small amounts of wave activity. But now, new research suggests that those lakes and seas might be quite fizzy at times – with periodic bursts of nitrogen bubbles.