Cassini - Plunge into Saturn

Cassini Mission to the Final Stage:

        Cassini has begun transmitting data -- including the final images taken by its imaging cameras -- in advance of its final plunge into Saturn on 15th September 2017. The spacecraft is in the process of emptying its onboard solid-state recorder of all science data, prior to re-configuring for a near-real time data relay during the final plunge. Unprocessed raw images are available here. The communications link with the spacecraft from now through the end of mission.

NASA's Cassini spacecraft is on final approach to Saturn, following confirmation by mission navigators that it is on course to dive into the planet's atmosphere on Friday, 15th September 2017.

Cassini is ending its 13-year tour of the Saturn system with an intentional plunge into the planet to ensure Saturn's moons - in particular Enceladus, with its subsurface ocean and signs of hydrothermal activity - remain pristine for future exploration. The spacecraft's fateful dive is the final beat in the mission's Grand Finale, 22 weekly dives, which began in late April, through the gap between Saturn and its rings. No spacecraft has ever ventured so close to the planet before.

The mission's final calculations predict loss of contact with the Cassini spacecraft will take place on 15th Sept at 7:55 am. Cassini will enter Saturn's atmosphere approximately one minute earlier, at an altitude of about 1,195 kilometers above the planet's estimated cloud tops. During its dive into the atmosphere, the spacecraft's speed will be approximately 113,000 kilometers per hour. The final plunge will take place on the day side of Saturn, near local noon, with the spacecraft entering the atmosphere around 10 degrees north latitude.

When Cassini first begins to encounter Saturn's atmosphere, the spacecrafts attitude control thrusters will begin firing in short bursts to work against the thin gas and keep Cassini's saucer-shaped high gain antenna pointed at Earth to relay the mission's precious final data. As the atmosphere thickens, the thrusters will be forced to ramp up their activity, going from 10 percent of their capacity, the thrusters can do no more to keep Cassini stably pointed , and the spacecraft will begin to tumble.

When the antenna points just a few fractions of a degree away from Earth, communications will be severed permanently. The predicted altitude for loss of signal is approximately 1,500 kilometers above Saturn's cloud tops. From that point, the spacecraft will begin to burn up like a meteor. Within about 30 seconds following loss of the signal, the spacecraft willbegin to come apart; within a couple of minutes, all remnants of the spacecraft are expected to be completely consumed in the atmosphere of Saturn.

Due to the travel for radio signals from Saturn, which changes as both Earth and the ringed planet travel around the Sun, events currently take place there 83 minutes before they are observed on Earth. This means that, although the spacecraft will begin to tumble and go out of communication at 6:31 am at Saturn, the signal from that event will not be received at Earth until 83 minutes later.

More Information:

Unprocessed Raw Images of Cassini available at : https://saturn.jpl.nasa.gov/galleries/raw-images

Discoveries of Cassini at : https://www.nasa.gov/ebooks

Cassini Final Plunge into Saturn : https://saturn.jpl.nasa.gov/grandfinale

Cassini Grand Finale in Twitter : https://twitter.com/CassiniSaturn

Cassini Grand Finale in Facebook : https://www.facebook.com/NASACassini

Know more about Cassini-Huygens Mission : https://saturn.jpl.nasa.gov/

Credits: Text and Image - National Aeronautics Space Administration