Nasa’s Cassini sends its final pictures before rapid plunge

It was not a clean or swift death.

For Cassini, the “long walk” to the moment of execution began on September 11 with a final fly-by of Saturn’s largest moon, Titan.

The distant moon’s gravity nudged the spacecraft onto a course that sealed its fate as it sped back to the ringed planet, capturing a last batch of stunning images on the way.

On this trajectory, Cassini would sail too close to Saturn to survive.

Four days later, just after 9.30am UK time and high above the planet, the probe reconfigured its systems to begin gathering data and transmitting it back to Earth in near real-time.

At around 12.53pm, and still more than 1,000 miles above the cloud tops, Cassini began to penetrate Saturn’s thick hydrogenrich atmosphere.

Firing attitude thrusters to maintain position, the probe sampled and analysed the gases rushing past it, providing invaluable data that could not have been obtained from a normal orbit.

But this was Cassini’s last gasp. Three seconds later, some 930 miles above Saturn’s cloud tops, the buffeting winds overcame its attempts to stay in control and keep its dish antenna pointing accurately at Earth.

As soon as the antenna swerved away from its target, all contact with the mission controllers and scientists on Earth was lost.

In the following seconds Cassini’s on-board computer would have run through its fault protection procedures in a desperate bid to keep the craft in a safe, stable state.

Scientists can only imagine what is likely to have happened next as the craft tumbled through the atmosphere at 77,000mph.

An artist’s impression of Cassini turning into a fiery meteor as it breaks up in Saturn’s atmosphere. Picture: PA.

Cassini above Saturn’s northern hemisphere. Picture: PA.