NASA Cassini probe's next plunge into Saturn rings; know all about the spacecraft's death-defying 22 scheduled dives

NASA’s Cassini spacecraft will be heading for yet another death-defying dive between Saturn and its rings at 3:38 pm EDT on Tuesday, the US space agency has said. The cameras mounted on Cassini will capture close-up images as the spacecraft passes through the narrow gap.

This will be the second of the 22 risky dives planned by NASA for Cassini. The question is will it survive? NASA is keeping its fingers crossed.

During the first dive of the Grand Finale, Cassini lost contact with NASA when it was closest to Saturn. This time too, it will be out of contact and will transmit data back to Earth on May 3, the US space agency said in a statement.

During its first dive on April 26, NASA Cassini spacecraft found that the region appears to be relatively dust-free. The team Cassini would with this information now move forward with its scheduled plan of science observations.

"The region between the rings and Saturn is 'the big empty,' apparently," said Cassini Project Manager Earl Maize of NASA's Jet Propulsion Laboratory in Pasadena, California.

"Cassini will stay the course, while the scientists work on the mystery of why the dust level is much lower than expected," Maize said.

During the first dive, because of the possibility of presence of dust in between the gap, Cassini’s saucer-shaped main antenna worked as a shield. However, Cassini team was delighted that ‘Plan B’ option may no longer be needed for upcoming dives.

Cassini reached Saturn’s orbit in 2004 after it was launched in 1997. It performed a last close flyby of Saturn’s moon Titan on April 22 and then began its ‘Grand Finale’, a phase that will be followed by the death of the Cassini.

During the Grand Finale, Cassini loops Saturn approximately once per week, making a total of 22 dives between the rings and the planet. With first dive being successful, now 21 dives remain. 4 out of these require Cassini to pass through the innermost fringes of Saturn rings, where the use of antenna becomes necessary to be able to work as a shield.

NASA Cassini spacecraft, which is a joint endeavour of NASA European Space Agency (ESA), and the Italian space agency (ASI), will die after plunging into the atmosphere of Saturn on September 15.

First of the 22 Cassini dives:

Cassini made the dive at the innermost ring of the planet, where no spacecraft has ever dared to go before. NASA has planned total 22 close encounters in the last phase and last week’s dive was the first of these.

"Cassini spacecraft has once again blazed a trail, showing us new wonders and demonstrating where our curiosity can take us if we dare," National Aeronautics and Space Administration planetary sciences chief Jim Green said in a statement.

What Cassini is supposed to do in Grand Finale?

During the last phase, Cassini is expected to capture several small inner moons and observe Saturn’s winds, clouds, auroras and gravity.

In its last phase, the Cassini will perform a long string of historic firsts and Wednesday’s successful manoeuvre was the latest one. However, Cassini is soon going to die after its almost 20-year space odyssey.

Why NASA is killing Cassini probe?

In October 1997, NASA had launched Cassini probe to study Saturn and its moons. Cassini arrived at the orbit of Saturn in July 2004. After years of observations and data collection, Cassini is now ageing and is running low on fuel. Hence, NASA has decided to kill Cassini, which will meet its death after plunging into the atmosphere of Saturn.

" reason for this ending to the Cassini mission is something that NASA is very worried about – contamination of our life forms on planets and moons that may harbor other forms of life," says Nicholas Suntzeff, a professor of Observational Astronomy at Texas A&M University, tells the Monitor via email. "The moons of Saturn – Enceladus and Titan – could have life or complex organic molecules that are the soup out of which life forms."

What NASA scientists say about Cassini?

"NASA and the Cassini team's devotion to the mission are an example for all of us," Harold C. Connolly Jr., chair of the department of geology at Rowan University in New Jersey, tells The Christian Science Monitor in an email. "I remember as a child living in southern New Jersey being glued to the TV when the Voyager images came back to Earth, and now I am an upper manager of a NASA space mission – I hope Cassini-Huygens has motivated a new generation of future scientists and explorers."

Dr. Connolly is currently working on the OSIRIS-REx program, NASA's first mission to collect an asteroid sample and return it to Earth for analysis. 

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"Cassini has provided a better understanding of Saturn's ring system, why it exists, the weather conditions on Saturn, and the mysteries of its largest moon, Titan: A truly primitive world potentially similar to what Earth was like in the earliest days of its life," Connolly adds. "From an engineering point, we as humans have learned how to navigate and fly around the massive planet of Saturn, which provides key information on how to fly to and around other planets. We have also learned the extent of the lifetime of various payload instruments, those critical to meet science objectives and those needed for navigation."

"No spacecraft has ever been this close to Saturn before," said Cassini project manager Earl Maize in a NASA statement. "We could only rely on predictions, based on our experience with Saturn's other rings, of what we thought this gap between the rings and Saturn would be like."

ALSO READ | Death of NASA's Cassini: Spacecraft makes daring encounters with Saturn rings, communications with probe blurred

When will NASA Cassini spacecraft meet death:

NASA officials are not sure whether Cassini will survive all its ring dives. The gap between Saturn and the rings is about 1,500 miles (2,400 km) wide and likely littered with ice particles.

Cassini is travelling through the gap at a relative speed of about some 77,000 mph (124,000 kph) so even small particles striking the spacecraft can be deadly.

The Cassini spacecraft will perform similar manoeuvres during its subsequent dives, the second of which is scheduled for Tuesday.
On its final dive on September 15, Cassini will explode like a meteor and destroy itself by flying directly into Saturn's crushing atmosphere.

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NASA plans to crash the spacecraft into Saturn to avoid any chance Cassini could someday collide with any ocean-bearing moons that have the potential to support indigenous microbial life.