On Oct. 28, NASA's nuclear-powered Cassini spacecraft flew just 30 miles above Saturn's icy moon Enceladus to "sniff" its vast subsurface ocean.
Just two days later, NASA has just released the first images from the pass; and they are stunning. Here's what the probe saw as it flew toward the moon.
These are just a few of the many preliminary unprocessed images that NASA has received from the flyby, which are giving NASA scientists their closest-ever peek at Enceladus' rugged, icy surface.
Researchers will start analyzing data from the spacecraft's gas and dust "sniffing" instruments - which directly sampled the moon's gas plumes and tiny, icy dust particles - very soon, NASA said in a press release.
This deeper analysis will give scientists more solid clues about the chemical composition and potential hydrothermal activity hiding beneath Enceladus' large, planet-wide ocean. Here's what the plumes on the moon's southern pole looked like on the probe's approach.
NASA/JPL-Caltech/Space Science Institute
Droplets of moisture spray through geysers on Enceladus' south pole.
The Cassini spacecraft's sampling is a particularly exciting event because scientists think Enceladus is, aside from Earth, the most likely world in the solar system that's capable of supporting life - we just haven't gotten a close enough look yet.
Cassini has studied Saturn and its moons since 2004. During that time, the spacecraft discovered a giant plume that spouts water vapor, ice, and other chemicals from Enceladus' south pole. This watery plume is likely bursting from a vast, salty ocean beneath the world's frozen crust, which looks magnificent in this new picture.
NASA/JPL-Caltech/Space Science Institute
Enceladus's icy, rugged surface, taken by the Cassini flyby on Oct. 28
Scientists already know that the plume contains organic material - the building blocks of life. They also suspect that the ocean it comes from is hydrothermally active. This would make Enceladus even more likely to support alien microbes, since they're what would keep the water warm and create mineral nutrients.
Here's the first of likely many close up images of the surface of Enceladus, though we aren't sure if this is the closest view of the moon. You can clearly see the rough ridges on the surface ice, even in this unprocessed view.
NASA/JPL-Caltech/Space Science Institute
Enceladu's icy, rugged terrain, captured on the Oct. 28 flyby.
Cassini barreled through the moon's plume at 19,000 mph on Oct. 28, using gas and dust sensors to sample the plume:
This was the lowest pass through the plume that Cassini has ever made, according to NASA. And while the robot wasn't capable of directly detecting signs of life, scientists expect to gain a lot of insight from the flyby.
Cassini zoomed so close to the surface, it may have detected heavier organic molecules than it did during previous, higher passes through the plume. This could tell planetary scientists a lot more about the plume's chemistry, help verify whether or not the ocean is hydrothermally active, and offer clues as to how a stream of water vapor and ice could break through the moon's miles-thick frozen crust.
All of these insights will ultimately tell us more about the icy world's potential of harboring life.
The next and final close flyby of Enceladus will happen on Dec. 19. At that point Cassini will analyze the amount of heat radiating from the inside of the moon.
Check out more raw images from the Oct. 28 flyby here.