Cassini's mission will come to an end with a plunge into Saturn's atmosphere, which will destroy the spacecraft launched in 1997. (NASA/JPL-Caltech)

An important thing to know about Cassini, the plucky little NASA spacecraft featured in today's Google doodle, is that it didn't need to die this way.

When the probe launched toward Saturn in 1997, scientists had no idea that it was about to discover geysers on the moon Enceladus — now considered the best place in the solar system to look for life. In 2005, the spacecraft detected plumes of water erupting from the surface of that frozen world. Just this month, we found out that Cassini also found ingredients for life spewing from the moon.

But Cassini has been running out of power for years, and NASA can't risk the chance that it might crash into Enceladus and contaminate it. So last week, the space agency beamed the command for Cassini to start a series of deep dives toward Saturn before eventually crashing into it. Today, the probe got closer to Saturn than any human-made object ever has before slipping between the planet and its rings. It's slated to do 22 more dives  — one every week! And on Sept. 15, the spacecraft will send its last set of images back to Earth and then plunge straight into the planet, burning up in the gas giant's atmosphere.

In other words, Cassini is so good at its job that it necessitated its own death. And now it's going to sacrifice itself for the glory of science and the good of alien-kind (you know, if aliens actually exist).

That's just the kind of spacecraft Cassini is. Which is why basically all of space Twitter is reacting to the end of the mission like this:

Look, I know that you're not supposed to anthropomorphize things in science. But how can we help it? Cassini is literally the little spacecraft that could. Before it launched, NASA had only flown past Saturn and gotten quick glimpses of the sixth planet. But Cassini has orbited the planet for 13 years and made a series of stunning scientific discoveries. In addition to finding geysers on Enceladus, Cassini has …

  • Delivered the first-ever lander to the outer solar system: the Huygens lander, which plopped down on Saturn's moon Titan in 2005. Huygens introduced us to a chilly world with lakes and rivers of methane that could help scientists learn what Earth looked like before life evolved.
Four views of Titan taken during Huygens's descent to the surface. (ESA/NASA/JPL/University of Arizona)
  • Discovered several previously unknown moons of Saturn, including tiny egg-shaped Methone.

A 2012 image of Methone taken by Cassini. (NASA/JPL-Caltech/Space Science Institute)

Mysterious spokes in Saturn's rings. (CICLOPS/JPL/ESA/NASA)
  • Witnessed a historic, 30-year storm on Saturn.
This image, taken by NASA's Cassini spacecraft in 2011, shows a huge storm in Saturn's northern hemisphere. (NASA/JPL-Caltech/Space Science Institute)
  • Made the whole Earth smile. On July 19, 2013, Cassini pointed its wide-angle camera past Saturn's rings and back to Earth to snap a photo. In the image, our planet is little more than a tiny blue dot. But of all the fascinating worlds Cassini has encountered — Enceladus with its geysers; Titan with its hydrocarbon lakes; cute little ravioli-shaped Pan; Saturn itself, with its swirling colors and dazzling rings — Earth is still the only place we can call “home.”

Earth is a tiny blue dot in the lower-right-hand corner of this 2013 image taken by Cassini. (NASA/JPL-Caltech/Space Science Institute)