NASA's famed spacecraft, Cassini, which was launched some 20 years ago to circle and study Saturn, finally approached its last day on Friday. It has run out of rocket fuel, as expected, after a journey of some 4.9 billion miles (7.9 billion kilometers). I mean, it as the same distance between Earth and Pluto which is approximately equal to 4.67 billion miles (7.5 billion kilometers).

FYI, Cassini was an international project that cost $3.9 billion and included scientists from 27 nations and has transformed the way we think about life elsewhere in our solar system.

Cassini was launched from Cape Canaveral, Florida in 1997 and then it spent seven years in transit followed by 13 years orbiting Saturn.

Dates that will be marked in the history of space science

© Phys

"It will be sad to see Cassini go on Friday, especially as the instrument we built is still working perfectly," said Stanley Cowley, professor of solar planetary physics at the University of Leicester.

He further added, "But we recognize that it is important to bring the mission to an end in a tidy and controlled manner."

The spacecraft was set to see its end in Saturn which is the furthest planet visible from Earth with the naked eye, shortly after the spacecraft's final contact with Earth at 7:55 am (1155 GMT). 

They got to defunct Cassini to prevent any damage it may cause to Saturn's ocean-bearing moons Titan and Enceladus. The reason being scientist do not want to harm those moon's surrounding when sending another spacecraft for future exploration. According to them, these moons may contain some form of life.

If you are not aware, three other spacecrafts have flown by Saturn. The Pioneer 11 in 1979, followed by Voyager 1 and 2 in the 1980s, but none have studied Saturn in such detail as the Cassini did.

Watch ‘NASA at Saturn: Cassini's Grand Finale' below

This is what the community had to say about its demise

Andrew Coates, head of the Planetary Science Group at Mullard Space Science Laboratory at University College London

He said, "The mission has changed the way we think of where life may have developed beyond our Earth".

He added, "As well as Mars, outer planet moons like Enceladus, Europa, and even Titan are now top contenders for life elsewhere".

"We've completely rewritten the textbooks about Saturn."

Mathew Owens, professor of Space Physics at the University of Reading

He said, “Some 4,000 scientific papers have been based on data from the mission.

"No doubt scientists will be analyzing the information from its final, one-way trip into Saturn's atmosphere for years to come," Owens said.

Some astonishing facts about Cassini you might not know

© Cassini - NASA

1. The spacecraft has been named after the French-Italian astronomer Giovanni Domenico Cassini. In the 17th century, Giovanni discovered that Saturn had several moons and a gap in between its rings. 

2. It was a 22 by 13 foot (6.7 by four meter) spacecraft. It is credited with the discovery of icy geysers erupting from Saturn's moon, Enceladus. Also, eerie hydrocarbon lakes made of ethane and methane on Saturn's largest moon, Titan.

3. During it's orbital duration, it discovered six more moons around Saturn, a giant storm that raged across the planet for nearly a year and three-dimensional structures towering above Saturn's rings

4. In 2005, it released a lander called Huygens on Titan. With that, it marked the first and only such landing in the outer solar system, on a celestial body beyond the asteroid belt. Huygens itself was a joint project brought into life by European Space Agency, Italian Space Agency, and NASA.

The final numbers

© NASA

Scientists believe that before Cassini disintegrates like a meteor, it will reveal even more about the makeup of Saturn's atmosphere.