The second or third milestone is cancellation.
Seems to me that NASA needs to pick a specific goal and stick with it.
The closest of the 2 water worlds. Enceladus being much further and orbiting Saturn. I am very interested in seeing what they find.
Would love it more if people were part of a hands on mission
Captian! There be Whales here!
Does the Koran approve of this mission?
"Yeah. No meteor craters."
"Good observation. The entire icy surface is continually cracking and being remade, reforged, all the time. It is geologically active and is very much alive."
"What drives it? The energy source? Is it the internal decay of thorium and other radioactives like on Earth?"
"No. It gets its energy from another source, a big one."
"Which is?"
"Tidal flexing. Jupiter's huge gravity field pushes and pulls on the surface of Europa as it rotates. Think of it like the tides on Earth, only much more powerful. Now look here." She sliced the moon open. "There is a 40 kilometer layer of ice that is hiding a huge underground world-spanning ocean. It has more water than all of Earth's oceans combined."
"Neat. Let's go down and check it out."
They were now deep within the ocean. Skuld looked around. "Hmm.. let's see. Ah. Found one. A smoke vent." She translated their position towards it. Keiichi then saw a ragged looking structure that looked like a mini-volcano. It was belching what looked like thick black smoke. Surrounding the vent was a mass of writhing white tubular worms. Some other creatures, white crustaceans, were crawling around the tube worms. They appeared to be grooming them.
"This is a hydrothermal exhaust vent. Tidal flexing heats up Europa's core, and that heat works its way up to the ocean bed through vents like this one. That vent is pumping out all sorts of good stuff: organics like methane and ammonia, hydrates, sulfides, calcium, lots of stuff, all at high temperatures. The exhaust from these vents is over 400C, hotter than the boiling point of water. It doesn't boil because of the tremendous pressure. And yet you see all this wonderful life living around it. They are called thermophiles, organisms adapted to living at high temperatures.
Life bloomed around the vent. Keiichi saw it everywhere: amphipods, copepods, gastropods, annelids, bivalves of every shape and description. But no color. Everything was white.
"It's beautiful."
"Hey, you wanna see a whale?"
"Yeah."
They translated up. "The base of the biosphere are those black smokers. Not all life is limited to those places. For example, there is a creature called the balloon fish that indigests great quantities of that organic black gunk that causes the fish to blow up to several times its normal size. Then they swim up near the top of the ocean and belch it all out as they release their fertilized eggs. The eggs float down with all the gunk. They hatch and eat the nutrient rich cloud as it slowly descends."
She looked up. "But another creature feeds on it. And here comes one now."
It was huge, a white streamlined entity with eight fins. It had an open maw that swept slowly into the cloud of organic material, straining it through enormous baleen gills. It had no eyes.
"Wow.."
"And there are black smoker vents on Earth that are just like those on Europa, with life forms that are just as weird, with whole ecosystems that don't depend on the sun for energy. Worlds with underground oceans like Europa are in fact a rather common form of life in the galaxy. It's everywhere. And some of it is pretty weird, let me tell you."
"I bet there's some really bizarre critters deep in Earth's oceans too."
"Oh yeah, heh."
"Cool. Let's go see them!
[ Excerpt from After Ragnarök, chapter 29. ]