Do you know the many surprising connections between the deepest parts of space,
and the deepest recesses of our ocean? Both are cold, dark places, where humans cannot breathe,
and where the pressure alone is enough to kill you. Both upset our normal experiences of gravity,
providing explorers with a strange weightlessness or buoyancy if they
could somehow survive being there in the first place. And both contain many unsolved,
captivating mysteries. Our oceans are filled with life we’ve never seen before. And who can
say what lurks in the unexplored corners of space? I was initially caught off guard when I heard that
NASA had turned its attention towards exploring the hadal zones deep in the ocean. After all,
NASA is normally all about space. What are they doing deep under the water, and on Earth?
I’m Alex McColgan, and you’re watching Astrum. Put on your diving gear, and join me in a world
of undersea facilities, uncanny life, and an environment so hostile that we’ve mapped more of
Mars than of this terrain on our own planet. In 1957, a year before NASA was founded,
a paper published in the Journal of the Royal Society of Arts claimed: “the deep oceans cover
over two-thirds of the surface of the world, and yet more is known about the shape of the surface
of the moon than is known about that of the bottom of the ocean”. This was a reference to the fact
that in the world before echo-sounding technology was commonly used to map the sea floor, we didn’t
know much about the topography of what was down there. We’ve come a long way since then. But
while we have mapped the Moon thanks to satellites and telescopes, we have still only mapped 23.4%
of the ocean floor in high resolution. In fairness, this still represents an
area of 120 million square kilometres, about 3 times the Moon’s surface area, so the old saying
no longer holds entirely true. Hence why we can instead talk of Mars, which has a surface area
of 145 million square kilometres. But still, it’s a profound gap in our knowledge of our own world.
NASA was founded in 1958 with the purpose of expanding human knowledge of phenomena
in the atmosphere and in outer space, and developing vehicles and technologies that
would help them to do so. Exploring the ocean was not originally on their radar (or sonar). However,
in 1978 NASA began monitoring the ocean with their first dedicated oceanographic satellite,
SEASAT, which was capable of collecting data on sea-surface winds, surface temperatures,
wave heights, and other features. This helped them learn more about our planet’s oceans and
their impact on the global climate. Still, some of NASA’s most exciting forays into the
ocean only began at the turn of the Millenium. One way in which the sea can prepare astronauts
for space is through simulated space experiences. About 8.7 km off Key Largo
in Florida is the world’s only undersea research laboratory: Aquarius Reef Base. Built in 1986,
it is a small, 3-roomed habitat large enough to house 6 people at a push, with a main room that
combines sleeping and living quarters, an entry dock, and a wet porch for entering the sea around
it. It was originally designed to help “aquanauts” remain at the bottom of the sea for weeks at a
time through a technique known as saturation diving. By remaining at the depth of 19m, the
human body becomes saturated with gas dissolved in its bloodstream, which allows these researchers to
stay at depth without ill effects for much longer periods of time; 9 hours for one dive, rather than
1 or 2 hours. This made it ideal for biologists wanting to study the local environment in situ.
In 2001, however, NASA, along with other space agencies such as ESA,
realised that it made for a great space training location. The cramped living conditions mimicked
those found on the international space station, so astronauts who spent a week at Aquarius Reef
Base would get a vital taster of what life would be like up there. It also allowed them to practice
performing experiments, and generally get used to the expected and unexpected aspects of life
in a hostile environment. NASA began the NEEMO program, or the NASA Extreme Environment Mission
Operations, and that same year began sending their astronauts to the habitat. There have been 23
NEEMO missions since then, merging astronaut crews from a variety of different space agencies, which
lasted up to 3 weeks. Astronauts there became aquanauts and got the chance to don deep sea
suits, getting a taste for what “spacewalks” might be like outside of our planet, readying them for
the day humans return to the Moon, or go to Mars. This was not the only use NASA had for the ocean,
however. Perhaps the most significant training was not for NASA’s astronauts,
but rather for the machines that would one day visit the largest oceans outside
of planet Earth. Let’s now go deeper, and consider the exploration of alien oceans.
Our solar system is home to many large oceans outside of Earth. Jupiter’s moon Europa and
Saturn’s moon Enceladus – to name just two – have significant bodies of water beneath
their kilometre-thick icy surfaces. In spite of being only one fourth of the Earth’s diameter,
scientists believe that Europa holds twice as much water as all of our oceans combined.
This is an intriguing concept, as even though no sunlight penetrates down to those depths,
the mixture of liquid water bordering a rocky inner crust would make both
of these locations ideal candidates for life. Scientists have considered how to best test to
see if life really has arisen in the oceans of icy moons. In 2024 NASA will launch the Europa
Clipper, with the mission to fly by the moon Europa and scan it to learn more about the
depth of its icy shell, to try to determine the composition of its oceans, and generally get a
better picture of the moon as a whole. However, Europa Clipper will only be laying the groundwork
for future missions, which one day might see “cryobots” melting through the 10-km-thick icy
shell of Europa using nuclear-powered radiators, to penetrate its oceans and see firsthand what
lies below. Once down there, no radio signal will be able to easily reach them – messages
will be relayed via a vast cable brought down through the ice along with the cryobot.
This means that such cryobots will need to be able to autonomously descend a further 100-200
km, to explore the dark, chilling, and highly pressurised environment they’re likely to find,
to see what alien life might swim in those waters. So, with a mission objective on the horizon
to explore deep dark waters in search of never-before-seen life,
what better place to start than the unexplored oceans we already have at home?
The deepest parts of the oceans on Earth are only 11 km deep, but due to the gravitational
differences between Europa and Earth, the pressure you’d experience between the two
are much more comparable than you might think. Europa’s hundred-km-deep ocean is
thought to have a hydrostatic pressure between 130-260 MPa, which if it existed in an ocean
on Earth would equate to a depth of around 13-26km. This is much better than if you’d
had to go 100’s of km down on Earth, but it’s still no picnic. Pressure at the bottom of the
Mariana Trench – the deepest place in our ocean – is 1,100 times the pressure on the surface,
which is enough to crush the individual cells in the human body, or to implode most submarines.
And yet, life survives here. And it doesn’t just survive – it thrives. The Deep Sea explorers of
the Galápagos Hydrothermal Expedition in 1977, using a specially reinforced remotely operated
vehicle that could survive those pressures, were shocked to discover not a barren wasteland, but
thriving ecosystems gathered around hydrothermal vents on the ocean floor down there. Tube worms,
crabs, and fish were found in rich abundance. As scientists performed more dives, they found
all manner of strange lifeforms down there – shrimp-like amphipods the size of your hand.
Giant, ethereal “bigfin squid” squid that were 8 metres long and looked positively alien. In
the depths between 6000 and 11,000km, in an area known as the Hadal zone (named after the god of
the underworld, Hades), life had learned to adapt to conditions in ways no-one could have imagined
possible. And this incredible adaptability gives scientists a better understanding of
what might be possible on other worlds. The deepest parts of the ocean are mostly
found near the fault lines of continental plates, where one plate subducts under another. These deep
trenches create a unique v-shaped environment that channels organic debris from above down into a
sludgy pool. Whenever a carcass falls down here, the organisms in the hadal zone are somehow able
to quickly detect it and arrive within minutes. Other organisms rely on the nutrient-rich liquids
pumped out of thermal vents. If you added up all these trenches into one land-mass,
you would end up with an area the size of Australia - a whole unexplored continent.
NASA wants to explore these regions using autonomous drones – perhaps whole swarms of
them – that would be able to detect locations of interest such as thermal vents, and would be able
to map out the terrain using cameras and onboard AI similar to that used by the Perseverance rover
on Mars. It’s a challenging task. Not only would such a drone need to be able to withstand the
excessive pressure, but the temperature around such thermal vents can spike to hundreds of
degrees. Drones would need to be able to survive rapid temperature swings if they are to survive.
In 2014, one such deep sea drone known as Nereus was sent into the Kermadec Trench,
off the coast of New Zealand. This is the area NASA has selected as a testing ground for
its new equipment. However, sadly Nereus was not able to survive the pressure down there,
in spite of having succeeded on hadal dives before, and it imploded. Pieces of plastic
were later found floating to the surface. NASA’s latest drone is Nereus’ descendent, a smaller,
lighter autonomous submarine known as Orpheus. Orpheus has yet to enter the depths of a Hadal
zone. Instead, it is being put through its paces in shallower waters. But if it works,
its lighter design would make it easier to transport on a rocket to the oceans
of Europa at some point in the distant future. Although … this dream might not be so distant
after all. In 2023, NASA’s Planetary Exploration Science Technology Office (PESTO) gathered a team
of 40 top-researchers from multiple fields in the California Institute of Technology to discuss
how close we might be to making this trip. A surprising amount of the technology needed is
already there. Their conclusion was that the mission was “feasible, scientifically compelling,
and the most plausible near-term way to directly search for life in situ on an
ocean world.” With the combined information being gathered by Europa Clipper, and the
technical experimentation being done with Orpheus and other autonomous submarines like it, perhaps
it is something we will see within our lifetimes – although no concrete plans have been made yet.
When it finally does happen, though, and a human-made drone starts to swim in those
dark seas across the gulf of space, what will it see? Perhaps it will feel strangely like home.
We are water-based lifeforms, here on Earth. The first large, complex animals formed in our
oceans. All life is dependent on water to live. Rather than arid rocks and dusty wildernesses,
there will be something strangely soothing about exploring oceans beyond our own,
like entering a place we already know, even though we’ve never been there before.
Does something lurk in those alien seas? Although it’s only speculation, the sheer fact that this
might be true is enough. To discover that life came to exist not once, but twice in just our own
solar system would have massive implications on life’s prevalence in the universe as a whole. It
would mean life is likely abundant, and we ought to be ready to see a lot more of it out there. But
proving it is the challenge. Only by perfecting the technology here on Earth will we be able to
crack open those frozen shells, enter those inky depths, and find the definitive answers we seek.
For NASA, their mission to find life in our solar system begins in our oceans.
Update on the Patreon: We are now 84% of the way to our goal of 1,000 astronauts
on Patreon and I cannot thank you enough for having answered the call. The closer
we get the more it's looking like I'll be able to expand our content here and bring
back Astrum answers so submit your video suggestions and questions over on Patreon
and if you'd like to become an Astrumnaut you can join the Patreon with the link down below
once again a huge thank you from myself and the whole astrum team I'll see you next time.
Meanwhile click the link to this playlist for more Astrum content.