Sci-tech

Nasa's Cassini probe ends its 4.9bn-mile mission

Nasa's Cassini probe ends its 4.9bn-mile mission

Nasa scientists are preparing to kill off the Cassini space probe with a spectacular suicidal dive into Saturn's atmosphere on Friday.

Cassini is the most distant planetary orbiter ever launched and has made many astonishing discoveries in its near 14 year adventure. "The haze has cleared remarkably as the summer solstice has approached", Cassini Project Scientist Linda Spilker said in a news conference September 13. The ice was feeding into the rings of the planet. There are some huge gaps in the rings where the atmosphere is silent and less dusty. This final in-depth trip provided some valuable information about the chemical composition of Saturn's atmosphere.

When Cassini arrived at Saturn, where one "year" lasts 29.5 Earth years, the gas giant went through northern winter, and Cassini was there to witness the planet's change of seasons. It send back some gorgeous snapshots along the way and, now that its extended mission is complete, it's time for the spacecraft to perform the ultimate sacrifice.

Earl Maize, an engineer at NASA's Jet Propulsion Laboratory said: "We'll be saddened, there's no doubt about it, at the loss of such an incredible machine".

Cassini was not alone on its journey across the solar system as the Huygens probe went along for the ride.

Along its way, Cassini (and its Titan-bound companion, the atmospheric entry probe Huygens) captured hundreds of thousands of images and taught us more about Saturn, its rings and many moons.

What kind of mission will actually follow up on the curiosities Cassini has piqued?

"We'll be able to look at some important constituents that we know are there because we've been measuring them, but we'll get a better idea, for example, of the hydrogen to helium ratio, and that's important in terms of understanding the formation and evolution of Saturn", he said.

The UVIS has already fostered "scores of dazzling discoveries" - including a salty, subterranean ocean on one of Saturn's moons which scientists think may have conditions favorable for primitive life. NASA did not want to risk Cassini crashing into any of Saturn's moons and potentially contaminating them with microbes from Earth.

On Friday, NASA's Cassini spacecraft will plunge into Saturn's atmosphere, marking the end of a historic mission. For the scientists who began working on the project in the 1980s, it is the end of decades of work culminating in scientific progress and never-before-seen images of Saturn's rings, moons and surface.

Since April, the craft has been making a series of dives between the planet and its rings in what NASA has dubbed The Grand Finale. The end of the mission will be marked by the last stream of data that comes in 83 minutes after it is beamed from Cassini.

No images will be taken during the final plunge into Saturn, as the data transmission rate required to send images is too high and would prevent other high-value science data from being returned. Four years became thirteen, as Cassini continuously exceeded expectations and NASA kept discovering new tasks for the probe. The Cassini mission could barely compete in dinner time conversation up against missions to mars, especially not when it was only in the planning stage.

In 2011, Cassini photographed a massive storm that erupted on Saturn, which lasted for several months.