- If we look at the vast size and age of the universe, it's nearly impossible for there not to be extraterrestrial life out there.

But it may be hundreds or even thousands of years before we have the technology to visit other stars to find aliens.

That's why scientists are also focusing on searching for life within our solar system.

And as crazy as it sounds, we may actually have a shot at finding it.

(bright music) While we may not know of any alien life living on Mars, for the past 22 years, Mars has had several robotic inhabitants.

And behind me is a replica of the Curiosity Rover, the precursor to the upcoming Mars 2020 Rover.

Launching in July of 2020 with an expected touch down of February 2021, the 2020 Rover has four key science objectives.

The first of which is to determine whether life ever existed on Mars, and the first step to achieving this objective is focused around water, which is why NASA has chosen the Jezero Crater as the landing site for Mars 2020.

Though Mars is currently presumed to be too cold to have liquid water, several billion years ago, Mars was once a warm watery world, and mission scientists believe the 45 kilometer-wide Jezero Crater was once home to an ancient river delta.

They believe that landing the 2020 Rover in an area where water and sediments once flowed gives us the best chance to discover Martian rocks that preserved ancient organic molecules and other potential signs of microbial life known as bio signatures.

- 2020 is the next rover destined to land on the surface of Mars, and our primary objective is to be the first step in Mars sample return.

Our rover will actually collect samples from the surface.

We'll store them into little test tube-like devices.

We'll drop them on the ground, and a subsequent mission will then come pick those samples up, launch them off the surface of Mars and send 'em back to the Earth.

To actually be able to have known rocks in our scientists hands that came from the surface of Mars, they're gonna be able to do science at a whole new level.

- So what are some of the challenges that come with those different environments the rover has to be in?

- I think the actual biggest challenge that we have ahead of us is that the materials and the hardware we use to collect that sample are very pristine.

They gotta be sterile so that when it brings samples back to Mars, we know it's material from Mars, not necessarily material that we brought to Mars with us.

- This is a replica of the Mars Curiosity Rover.

This is what a lot of the hardware is gonna be based on for the new Mars 2020 Rover.

This is so cool, it's big!

You don't realize how big of a payload they have to send all the way to a different planet.

There's a lot of really, really cool features about this rover.

Over here, there's something that kind of looks like a makeup palette.

That's actually for a color reference, so when the rover takes photos on the surface of Mars, we have a reference we know of from back here on Earth to then check the colors and figure out exactly what the colors look like on Mars's surface.

Even if it turns out that there was never life on Mars, there's at least one other place in our solar system that may hold the key to life.

Europa, Jupiter's icy sixth moon.

Europa's surface is smoother than any solid object we've ever seen in our solar system.

Scientists are confident that this smoothness is due to an extremely deep ocean of liquid water just underneath its frozen surface, and if it's proven to be true, it would be an ocean twice the size of all of Earth's oceans combined.

To study this, NASA's working on launching the Europa Clipper Mission in 2023.

- The simple answer to why Europa is, we believe it has a liquid water ocean.

One thing Earth has always taught us, anywhere we found water in a liquid state, we found life so we need to chase the water.

- But an ocean of water on its own isn't enough to produce life because while water may be necessary to facilitate living organisms, life also requires energy.

In order to power biological processes like maintaining cellular structures, growing and reproducing, living organisms need to extract energy from their environments.

Here on Earth, most living things, including humans depend directly or indirectly on the energy of the sun, but there are also organisms that exist without the energy of the sun and instead thrive in high pressure, near-freezing temperatures and pitch black darkness.

These creatures harvest their energy from chemical sources, such as life that feeds from hydrothermal activity on the ocean floor.

And this could be the key to life on places like Europa.

It's likely that the tidal squeezing from Jupiter's gravitational field provides the energy to keep Europa's ocean liquid, but we also believe that this energy could be causing volcanic activity, or hydrothermal vents, on Europa's sea floor.

If this is true, this could be infusing the liquid water with the energy and nutrients needed to support life below Europa's icy surface.

And so, we've done fly-by's of Jupiter before.

What has upgraded?

- Right.

- As far as what we're gonna be able to analyze on Europa?

- So those 10 instruments.

We're gonna have four remote-sensing instruments, essentially cameras in different wavelengths.

We have four In-Situ instruments, which means things that sniff, taste, and sense certain characteristics of Europa.

We have a dual frequency ice-penetrating radar, and then the last thing is the gravity science experiment using Doppler signals and radio tracking at closest approach for a number of fly-by's.

We can start teasing out the gravitational variations.

We're trying to answer this age-old question, right?

Ever since we've looked up at the stars, it's always been are we alone?

And we're getting to the point where we can start to actually, with robotic missions, answer that question.

- As scientists look for more clues out in the solar system and beyond, we might have to redefine what it means to be alive.

We have to be open to finding clues so alien, we may not even immediately recognize them.

Life on Mars, or Europa or planets and moons outside of our solar system, may not be familiar, and now that we've evolved into curious beings looking out at the universe, one of our prime goals is to find anyone or anything that's also alive and prove definitely that Earth is not the only place in the universe filled with life.

(bright music)