Cassini, the spacecraft launched towards Saturn in 1997, has done its best into providing information but the time has come when it has to be destroyed.
NASA decided to do that in order to prevent accidental crashing and contaminating a close-by moon where alien-life might exist.
But before Cassini disappears for good, it will do one last orbit between Saturn and its rings and collect as much new data as it can.
For almost thirty years, researchers have struggled to design, build, launch and operate an extraordinary mission in order to explore Saturn.
The golden nuclear-powered spaceship, Cassini-Huygens, or simply Cassini, was launched in October 1997, started orbiting Saturn in July 2004 and has been collecting data from the planet ever since.
But Cassini’s last day is coming soon. On Friday, September 15, 2017 it will be destroyed. That event is called the “Grand Finale”.
The reasons why Cassini is being destroyed were explained by the researchers during a press conference on April 4. The action will use the small amounts of Cassini’s fuel reserves and send it towards a destruction course with Saturn.
According to Earl Maize, an engineer at NASA’s Jet Propulsion Laboratory (JPL), apparently Cassini’s own discoveries were the reason for its downfall.
When Maize said that he had in mind a warm, saltwater ocean which Cassini discovered underneath the icy crust of Enceladus, a big moon of Saturn from where water is erupting into space.
In October 2015, Cassini flew through this combination of vapor and ice, “sampled” the material and indirectly discovered the content of the subsurface of the ocean. It was concluded that it’s the one which can support alien life.
“We cannot risk an inadvertent contact with that pristine body,” Maize said. “Cassini has got to be put safely away. And since we wanted to stay at Saturn, the only choice was to destroy it in some controlled fashion.”
But before Cassini is gone for good, Maize and the team of researchers from 19 nations are intending to gather every byte of data which the robot can provide, until it turns into a radioactive comet above Saturn.
The goal of Cassini’s mission was to orbit Saturn and explore the planet, its moons and its rings in as many flybys as possible.
Mission managers were planning that Cassini will gather as many magnetic readings and unseen images as it can and record gravitational data without being endangered or has burnt too much of its limited propellant.
However, 13 years later since the mission has begun, at almost 1 billion miles (1.45 billion kilometers) far away from the Earth, Cassini is running out of fuel.
Jim Green, the leader of NASA’s planetary science program, said that Cassini’s mission is coming to an end since the things it can now do are pretty limited.
Some maybe thought that NASA will send Cassini to another planet – Neptune or Uranus for instance, but in 2010 mission managers made a decision not to move Cassini from Saturn, claiming they could take in more science out of the mission there. But this decision sealed Cassini’s fate.
Cassini will begin its death circling on April 22, 2017 with one final fly by Titan. Titan is an icy moon of Saturn with a thick atmosphere, seas of liquid methane and rain. Titan is even larger than our own moon.
On April 26, 2017 Cassini will be put into Saturn through a narrow void between the planet and the edges of the planet’s rings. That void is 1,200 miles wide, which is almost the distance between the southern tip of California and the northern Washington state.
This is a one-way trip for Cassini, or as Maize said, they are going in but they are not going out.
Linda Spike who’s a Cassini project scientist and a planetary scientist at NASA JPL announced for the press that as they were approaching the planet they were receiving extraordinary views of the poles of the planet. Now they will be able to see the big hurricanes at the south and north poles.
During this last flyby Cassini will approach the hexagon-shaped feature of Saturn’s North Pole and perhaps finally we’ll understand what holds the hexagon in that specific shape.
Cassini will also provide photographs of the auroras of Saturn’s poles, measure the planet’s rings, reveal the material they consist of and even go deeper underneath the layers of thick clouds.
Thanks to Cassini’s sacrifice researchers may be able to give answers of the questions which they couldn’t answer before. Questions like: “What does the inside structure of Saturn look like?, How large its rocky core is?, or “How quick a shell of magnetic hydrogen around it rotates?
Cassini will have hours to collect one final batch of images before it “dies” on September 15, 2017.
Of course this 2.78 ton robot with its fragile instruments was not intended to crash into icy ring material at speed of 70,000 mph. It also wasn’t designed to survive the plunging into the thick atmosphere of Saturn.
However, scientists involved in this mission will do their best to keep the instruments safe in order to provide a perfect flow of data until the moment Cassini disappears forever.
First they’ll try to protect its camera and some other valuable parts with the cone-shaped primary antenna.
Researchers are getting prepared for all kinds of surprises. They said that in the end the spacecraft will end up exactly where they’ve planned even if it fails to communicate with Earth as they hoped for.
During the final spin, Cassini fill use the rest of its propellant in order to fight atmospheric pulling while trying to keep the antenna pointed towards Earth and sending its reading of the gases’ composition.
But this won’t last long.
“It will break apart, it will melt, it will vaporize, and it will become a very part of the planet it left Earth 20 years ago to explore,” Maize said.
Although ever member of the team of researchers is aware of what has to happen they can’t hide the sadness. All of them agree that it will be hard to say farewell to the efficient spacecraft which brought back so much science from the gas planet.