Life on Europa

The presence of ice and oxygen on Europa, one of Jupiter’s four moons, has lead scientists to think that the moon could harbor extraterrestrial life. Led by astrobiologist Kevin Hand at NASA’s Jet Propulsion Lab, scientists are using chilled vacuum chambers to simulate what life might be like on Europa with the hope that astronauts may one day travel there.

TRANSCRIPT

The presence of ice and oxygen on Europa, one of Jupiter's four moons, has led scientists to hypothesize that the moon could harbor extraterrestrial life.

Now, led by astrobiologist Kevin Hand at NASA's Jet Propulsion Lab, scientists are using chilled vacuum chambers to simulate what life might be like on Europa with the hope that astronauts may one day travel there.

Our partner, 'Science Friday,' has the story.

Oceans exist beneath the icy shells of moons of the outer solar system.

If we have learned anything about how life on Earth works, it's that where you find the liquid water, you generally find life.

And so if Europa's inhabited, if Enceladus is inhabited by microbes or some other creatures, how do we actually go about detecting those life-forms?

We can't wake up in the morning and go to Europa, so, instead, we wake up in the morning and go to the lab.

My name is Kevin Hand.

I'm a scientist at NASA's Jet Propulsion Laboratory in Pasadena, California.

In a way, what we're trying to do is sort of reverse engineer what's happening on Europa's surface and potentially figure out what kinds of chemical signatures might be indicative of biology within Europa's ocean.

So Europa's got this liquid water ocean, but it's covered by an ice shell that's a few to maybe as much as 20 kilometers in thickness.

No sunlight is actually going to get down to that ocean.

Does that mean it's kind of game over for life?

No.

The bottom of our own ocean has ecosystems powered by hydrothermal vents where the microbial communities do just fine without any sun.

If we were able to drill through the ice on Europa and drop a camera into its ocean and something swam up to the camera, then touchdown.

You've found life.

But it's going to be a while until we do that, and so, at least for the near-term exploration of these worlds, we're going to be limited to measurements that are made through spacecraft flying by, and through robotic vehicles that land on the surface and then grab some material off the surface.

So, what would we look for?

Much of what we do in our lab is re-create the surface of Europa at many different scales.

At the tiniest scale, we've got these chambers that we refer to as our 'Europa in a can.'

These are vacuum chambers that allow us to pump down to Europa temperatures, which is about -280 degrees Fahrenheit.

We can bring it down to the space vacuum of Europa's surface, and we can then irradiate it with energetic electrons or ions, which is what happens to ice on the surface of Europa.

We've put salts into the chamber because we think that Europa's ocean is salty.

We put it in, and it's a nice pure white.

We irradiate it under Europa conditions, take it out, and it's a brownish- yellowish color.

And some of that color sort of matches the discoloration on Europa's surface.

We've also put different carbon compounds in there, and sometimes we can create a little waxy goo, and that's interesting because maybe these organic compounds are not getting destroyed by the radiation, but instead they might be synthesized into larger compounds.

And then we've also put microbes in there and irradiated microbes, and look for the remnants of what would serve as a sign of microbial life.

We've got these stock-pot chambers that are kind of a quick MacGyver-y version to recreate Europa's surface, and then some of our experiments feed forward into the design of robotic landers and sampling systems.

Our team has built a vehicle that we call the Buoyant Rover for Under-Ice Exploration, and basically what it does is it floats on the underside of the ice and look at the ice/water interface.

Those capabilities will hopefully someday be used to explore these far and distant oceans on worlds like Europa and Enceladus.

You've got this incredibly cold ice on Europa's surface, and at that temperature, is it possible to even sample that ice, or is it so hard that you just cannot drill into it?

And we've done experiments to get at exactly that question, and turns out, with the right tools, we can put a saw blade down in and through that ice.

And then most recently, our team has created what we call The Ark of Europa.

This is a very large vacuum chamber and cooling system, and then there's a roughly 30-centimeter thick block of ice within there that is then subject to lights going back and forth, kind of like the rise and fall of the sun on Europa's surface, and that may create spikes and dips within the ice surface.

This is where our Ark of Europa will help, because we'll be able to re-create the surface structure of Europa.

There's still another -- phew! -- nearly 15 years or so to go before we maybe land on the surface and then sample the surface to look for signs of life.

But I predict that, within our lifetimes, we will potentially revolutionize our understanding of life in the universe and our place in it, and that's because we do have a pretty robust plan for exploring our solar system and beyond.