NASA has confirmed that it has lost contact with the Cassini space probe, which until the last moment was sending information as it descended into the atmosphere of the planet Saturn and went to its destruction. It’s the end of the Cassini-Huygens mission, a collaboration between NASA, ESA and ASI (Italian Space Agency), one of the most extraordinary space missions in history.

The birth of the Cassini-Huygens mission was the result of a collaboration between the European Science Foundation and the American Academy of Sciences in 1982, during the period of the solar system’s great exploration missions. At the initial stage it was proposed to send in the Saturn system a space probe to study the planet, its rings and its moons, especially Titan, along with a lander that landed on that moon, which was already considered very interesting.

The project was developed by NASA and ESA with some contributions from ASI during the 1980s but at some point there was a cencelation risk because of the budget cuts decided by the US Congress. However, the American-European cooperation also had a political value and eventually the mission received the necessary funds. There were also problems with some environmental groups that opposed the construction of probes powered by radioactive materials, in this case plutonium 238, for the risk of contamination in the event of a failed launch but the preparations continued regularly.

On October 15, 1997, the Cassini space probe and the Huygens lander were launched on a Titan IV-B/Centaur rocket from Cape Canaveral. The space probe was named after the Italian astronomer Giovanni Domenico Cassini, the lander after the Dutch astronomer Christiaan Huygens, two pioneers of the planet Saturn’s studies.

On July 1, 2004 Cassini became the first space probe to enter Saturn’s orbit. On December 25, 2004, the Huygens lander separated from Cassini to begin the series of maneuvers that on January 14, 2005 allowed it to land on Titan, where it kept on sending data for 90 more minutes.

For more than 13 years, the Cassini space probe navigated among Saturn’s moons studying them together with the planet and its rings. Already in 2005 the first Enceladus flybys returned detections that eventually led to a discovery that made history. The discovery of geysers in its south pole region and subsequent discoveries of other Enceladus features convinced the scientists that the moon had an underground ocean that today is considered to be one of the main candidates for hosting life forms outside the Earth.

The many discoveries made since the early years led to two extensions of the Cassini mission in 2008, called Cassini Equinox, and especially in 2010, called Cassini Solstice. That allowed to gather many more information on Saturn, its rings and moons, especially Enceladus and Titan.

Recently several lists of the major discoveries made thanks to the data collected by the Cassini space probe have been published but it’s difficult to determine which ones are the most important. Of course, Enceladus ended up at the center of a lot of attention but many discoveries still have to be fully evaluated.

Knowing that the space probe was running out of fuel, NASA planned the mission’s Grand Finale by sending Cassini into the void between Saturn and its rings starting at the end of April 2017. Today, Cassini entered Saturn’s atmosphere to disintegrate, a decision taken to avoid the risk of contaminations.

After 20 years in space any microorganism attached to Cassini is supposed to be dead but in the remote possibility that some survived NASA preferred not to risk contaminating Titan or Enceladus leaving Cassini at the mercy of gravity. Various instruments remained switched on untile the end to collect more data about Saturn’s atmosphere.

Almost 4,000 scientific articles based on data collected by the Cassini space probe and the Huygens lander have already been published but in these cases the studies continue for many years. This is a case in which it really would take an encyclopedia to include all the information gathered in this extraordinary mission.