spaceSpace and Physics

NASA's Groundbreaking Cassini Mission At Saturn Is About To End


Jonathan O'Callaghan

Senior Staff Writer

Artist's impression of Cassini at Saturn. NASA/JPL-Caltech

NASA is preparing for the planned demise of its Cassini spacecraft tomorrow, as the groundbreaking mission comes to an end with a plunge into Saturn.

It’s set to be an incredibly somber day, as the 13-year mission at Saturn comes to a close. The spacecraft is now on its final approach to Saturn, bringing an end to the final part of the mission, called the Grand Finale.


"The spacecraft's final signal will be like an echo,” said Earl Maize, Cassini project manager at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, in a statement. “It will radiate across the solar system for nearly an hour and a half after Cassini itself has gone."

Cassini is being sent purposefully into the atmosphere of Saturn to destroy the spacecraft and end the mission. This is because, as it runs out of fuel, engineers don’t want to lose control of it and accidentally contaminate one of Saturn’s potentially life-harboring moons like Enceladus.

Timings for the mission's end. NASA/JPL-Caltech

The action begins today. At 3.58pm EDT (8.58pm BST), Cassini will take its final image. Less than half an hour later it will begin transmitting its final data, including these last images, back to Earth. It takes about 83 minutes for a signal from Cassini to reach Earth.

Tomorrow morning at 1.08am EDT (6.08am BST), Cassini will pass the orbit of Enceladus for the last time. Two hours later, it will begin continuously sending data back to Earth.


At 6.31am EDT (11.31am BST), it will enter the atmosphere of Saturn. It will continue pointing its antenna towards Earth for as long as possible, sending back vital data on the atmosphere in the process.

After about a minute, it’s predicted Cassini will no longer be able to overcome the atmospheric drag, and its antenna will be forced away from Earth, leading to a loss of signal. Cassini will then be silent, bringing the mission to a close as the spacecraft disintegrates in the atmosphere of Saturn.

Cassini's path into Saturn's atmosphere. Each dot is 10 seconds apart. NASA/JPL-Caltech

Owing to the distance between Earth and Saturn, it’ll be 7.55am EDT (12.55pm BST) when we hear the final signal from Cassini. Its plunge will see it enter the day side of Saturn, with atmospheric entry beginning about 1,915 kilometers (1,190 miles) above the clouds of Saturn.

Its final transmissions will be received by NASA’s Deep Space Network antennas in Canberra, Australia. These will include data from eight of its science instruments, although there will be no images from the final moments. You’ll be able to watch the action from JPL Mission Control tomorrow live on NASA TV.


There will be plenty of tears and no shortage of words written about this incredible spacecraft. Our first and only Saturn orbiter, Cassini leaves a legacy of discovery and exploration that might never be beaten.


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