Transcriber: Aijia Yang Reviewer: Zsófia Herczeg
Space.
Its vastness, beauty and the allure of solving its mysteries
draw us to explore it.
I wanted to learn more about this vast universe
for as long as I can remember.
I’m a planetary protection engineer.
Within this discipline, it is my job to protect planets,
moons and other Solar System bodies from Earth life contamination,
and protect Earth from possible alien life forms
that may return on a vehicle
or within a sample we collected elsewhere in our Solar System.
We care if a few microbes from Earth make Mars their new home
because we don’t want to muddle the search for signs of life
on the Red Planet.
We rely heavily on detecting small details
about the geology and chemistry of other bodies
and connecting them to what we know
about the formation and evolution of life on Earth.
And while eventually,
humans and their mobile biomes will step foot on Mars,
it’s wise to learn as much as we can before that happens.
We want to know if life ever arose on Mars,
and so we do not wish to discover a microbe on the Red Planet
that hitched a ride on one of our rovers.
This is why we have the discipline of planetary protection.
Space exploration and the search for life are important,
and how we organize to do it safely matters
because if done right, it often pays dividends of all humankind here on Earth.
Science and space exploration
has always resonated with innate human curiosity.
This exploration allows us to test our limits
and better understand humanity’s place in the universe.
That's in our nature, I believe.
Educational programs and knowledge generated from space exploration
inspire the next generation of innovations and innovators.
I’ve seen career scientists with decades of experience
completely lose their cool and burst into tears
over witnessing the first videos
capturing the entry, descent and landing on Mars.
So it isn’t just for the youth to be inspired.
But here’s the thing.
Technology and innovation take time to develop,
and this takes persistence.
Most of our projects at NASA are decades in the making and execution.
It’s not like in the movies
when the technology needed to respond to a critical scenario
is developed in a few days.
Working out the process for returning a sample from Mars
took three decades of discussion and development,
with years worth of work still to go before we can actually get something back.
Sometimes our modern culture suffers detachment from reality
on the difficulty of these scientific processes
and the sheer persistence needed to discover and solve complex problems.
People want instant gratification and quick solutions,
and this impatience is the enemy of significant innovations
and meaningful, sustainable solutions for us humans on Earth.
It is also important to remember
that the biggest benefactors of space exploration so far
have been the people of Earth.
The space program has given us far better tools
for living a better, healthier life.
Social media, as we know it today,
is enabled by NASA tech in each of your cell phone cameras.
Hurricane behavior, water purification systems,
CAT scan technology
and tracking the impacts of air pollution are but a few examples.
So as we have learned about Earth and the life it harbors,
it informs us about how life might persist in the universe.
So what is the best way to search for it?
It starts with understanding
how life survives in the most extreme environments
here on Earth.
Our understanding of places like the bottom of the ocean
and the vents of active volcanoes is rapidly evolving.
New technologies are providing discoveries
that push the envelope of what was once understood to be true.
In example, we used to think that microbial life could not exist
in the driest of dry environments,
such as the Atacama Desert in northern Chile,
which gets mere millimeters of rain each year.
We have always assumed water meant life, and little to no water meant no life.
But that turns out not to be true.
DNA sequencing of soil samples collected from the Atacama revealed
that a wealth of organisms live in that dry environment
or were transported to the Atacama by desert winds.
There are other examples
of how life on Earth can survive in peculiar places.
Some microbes use the products of radioactive decay
as a source of energy.
A radiation and high heat resistant microorganism
called Deinococcus radiodurans
can survive far beyond the lethal dose of radiation to humans.
It does so by being efficient at repairing its DNA
damaged by high levels of radiation -
among its many other tricks.
Scientists are now studying it to further determine
if it might slow the clock of human aging,
which results from DNA damage to your cells.
Even the ruins of the Titanic
in the depths of the ocean, far from sunlight
are teeming with Halomonas titanicae,
who love using the ship's iron as a source of food.
These microbes can also survive in high salinity
or very salty environments.
Suppose we could unlock its secrets for surviving harsh environments.
That may lead to products
that help humans find ways to combat these conditions
more effectively and efficiently.
Because DNA sequencers are getting smaller and more affordable,
new bacteria are being discovered more frequently right here on Earth,
and in very harsh conditions.
But DNA is just one example of the biomolecule.
There are several biomolecules that, if found, could allow researchers
to get one step closer to determining if life exists beyond this planet.
For example, the SHERLOC instrument on NASA’s Perseverance rover
uses cameras, spectrometers and a laser to search for biomolecules on Mars.
Finding evidence of these particular signatures
could completely change our understanding of life
and its persistence within our very own solar system.
Again, our understanding
of how life takes root in extreme environments
evolves with each new discovery.
And as we learn that life on Earth
can survive in the most extreme and harsh environments,
we can imagine there is no shortage of harsh places out there
when we expand our gaze to space,
like some of the ocean worlds in the Outer Solar System.
So it’s vital to remove old assumptions
and rethink where life can emerge.
And this will take all the persistence and patience we can muster.
Another reason we should care if Earth microbes make Mars their new home
is because it’s the right thing to do.
There is an international treaty that outlines the principles
on how to appropriately explore our Solar System and beyond.
And the US is among the signatory countries.
Because we’re all part of an even larger ecosystem
spanning the Solar System,
we need to take care of that a few Earth microbes
don’t make Mars their new home.
Introducing new microorganisms can have a positive impact,
like ingesting probiotics for your digestive system,
but it could also have a negative ecological effect.
Even if such introductions don’t harm humans,
any change to an ecosystem can have unforeseen consequences,
like the consequences we see playing out on planet Earth.
It is impossible to know
whether the spread of life from Earth to other Solar System bodies
and vice versa
will have a positive or negative ecological impact.
It is critical to limit the spread of Earth life
as we explore these bodies
while protecting our own biosphere from samples from beyond our planet.
Even though the consensus of scientists
is that the chances of current life on Mars is extremely low,
NASA is planning to break the chain of contact
between any Mars dust and Earth,
and to securely contain any samples coming back from Mars
until their biological safety has been assessed,
or the samples are fully sterilized.
You can’t say that you’ve definitively detected life on Mars
if you have Earth-source contaminants all over your spacecrafts.
The catch when we send spacecraft to places like Mars,
they are assembled by humans from many different places
who use a wide variety of materials,
all of which might contain organic chemicals
that could be mistaken for life.
There’s no avoiding the facts that humans carry a microbial zoo with us
wherever we go.
In fact, we have more microorganisms in and on our bodies
than we have human cells.
Since humans are the most significant threat of contaminants
when assembling spacecraft,
the only way we can keep the spacecraft clean
is by putting a barrier
between the highly trained sacks of water and bacteria,
many of whom I count as friends,
and the spacecraft.
This barrier is called a clean room garment.
It is the head-to-toe protection that reduces the chance
that humans contaminate the spacecraft
as each part is assembled, tested and packaged for flight.
Other measures in place, like tacky mats on the floors
and air showers before entering the clean room
keep the human and environmentally associated microbes at bay.
Because it is relatively close
and probably had lots of liquid water billions of years ago,
Mars is the place to start searching for new life forms
and test the technologies
for a long term presence of humans in space.
Finding solutions to long-term astronaut survival on Mars
in the cold, radiation-heavy,
water-deprived, oxygen-deficient atmosphere
needs to be solved before humans can have a sustained presence on Mars.
The good news is solving those problems will likely also benefit our understanding
of surviving similar harsh environments here on Earth,
including innovations to make sustainable sources of drinkable water
and breathable air.
NASA has already made great strides
in developing fire-resistant polymer fabric,
which is currently used in spacesuits
and has directly benefited firefighters and their protective gear
and the military.
In a nod toward future human exploration,
the Perseverance rover, among other things,
carried spacesuit material to Mars
so that researchers could study this fabric’s long term survivability.
This could help us understand these materials’ life span
for when people use their spacesuits in the harsh Martian environment,
and this could lead to innovative protective gear here on Earth.
There are hundreds of billions of galaxies in the observable universe.
Each galaxy has hundreds of millions of stars.
And among those, any number could play host to orbiting planets.
And just a fraction of those planets are in the Goldilocks zone,
where it’s not too hot or too cold to harbor life as we currently know it.
So as we continue to find Earth-like planets beyond our solar system
and seek to find traces of biology in their atmospheres,
we must remember to be good custodians of our universe.
We must not forget to explore responsibly.
We’re obviously still figuring out
how to be the best guardians of our own planet.
My hope is that as we explore space,
we do it with the highest degree of integrity
and start to use that same philosophy to better ourselves here on Earth.
The least we can do as we explore the vastness of space
is to keep our germs to ourselves.
Thank you for listening.