This is a real photograph of a helicopter on the planet Mars. It was
built by humans on Earth and became the first machine to fly using aerodynamic lift
on an alien planet. NASA engineers have spent the past three decades working on
interplanetary exploration technology, going from a very small Mars rover up to a very
large Mars rover, and back down again to the miniature Martian helicopter. We
are looking at the first steps on a journey that will unlock the secrets of
the universe. This is how NASA reinvented their Mars rover. Before we can
really talk about wings on Mars, we need to establish our foundation on wheels.
Our upclose examination of Mars dates back to the mid nineteen seventies and the
Viking Landers. These were essentially scientific instrument clusters that made an epic journey all
the way down to the surface of the red planet and delivered first hand information
about the composition of Martian soil. NASA launched both Viking one and Viking two
in the summer of nineteen seventy six to take the most advantage of a close
proximity window between Earth and Mars that only opens once every twenty six months.
By placing two landers in different areas of the planet, NASA was getting the
most diverse sample range possible, But these were still just two scoops of sand
in a planet sized desert. The odds of finding an ancient fossilized Martian bacteria
using this method were not in our favor, so Mars landings were put on
hold for two decades as NASA worked on developing their solution for exploring the Great
Unknown. In December nineteen ninety six, NASA was ready to send a new
payload to Mars, the Pathfinder again. This was a scientific instrument station that
unfurled itself on the Martian surface to reveal a collection of scopes, cameras,
and meters. But Pathfinder also brought along with it a small prototype vehicle,
this little guy, Sojourner. Anyone who is around in the late nineties remembers
the original Mars rover. This thing was a pop culture icon. It was
incredible. We were driving around a remote controlled car on another planet. The
twenty first century had arrived. Sojourner was a technology demonstration. No one really
knew what was going to happen when you started to drive around a tiny car
millions of miles away on the surface of an alien planet, but there was
only one way to find out. The first Mars rover was about the size
and weight of a microwave oven. It had six wheels, each with their
own independent electric motor, and an experimental new suspension system that was called the
rocker Bogie. We know that the surface of Mars is not smooth and sandy
like a desert. It's littered with small chunks of jagged rock, and the
last thing NASA wanted was for their new rover to travel millions of miles through
space just to get hung up on a rock before it could do any science.
With this high tech suspension system, the rover could safely overcome oppsticles up
to one third of its own size. In this iconic photo taken by the
Pathfinder Landers camera, we can see the rover conducting an up close examination of
a large boulder. Because this rover was in such an early phase of development,
it didn't carry a whole lot of scientific equipment that was still mostly handled
by the Lander platform. But Sojourner was equipped with a front facing instrument called
an alpha proton X ray spectrometer, and that allowed it to determine the chemical
composition of any rock that it could drive up to. The rover was even
equipped with an early form of autonomous driving, not so different from what we
see in modern vehicles. It used a combination of camera vision and lasers to
identify obstacles and maneuver around the Martian landscape. Because the NASA team on Earth
could only communicate with the rover once per day, they would essentially have to
set a waypoint location that the rover would drive towards and then tune in the
next day to see where it ended up. So it was a pretty slow
process of exploration, with the rover covering about one hundred meters of driving in
its three months of operation. That doesn't sound like much, but it was
significantly more performance than NASA scientists had hoped for, and it gave the Space
Agency enough confidence to double down on the Mars rover in a very big way.
If one little Mars rover was able to captivate the world and write new
chapters in planetary science, then just imagine what two big Mars rovers might accomplish.
This was NASA's plan with the Mars Exploration rovers, Spirit and Opportunity Both
machines were launched on separate Delta two rockets in the summer of two thousand and
three, taking full advantage of that fleeting Mars transfer window. This time,
instead of a lander that deployed a separate rover, the lander was the rover.
After shedding its protective landing shell, each Exploration rover unfurled solar panels,
scientific instruments, and wheels, then set off into the Martian desert. It's
very difficult to get a sense for how big these machines actually are because we
have no known reference points on Mars, so where the Sojourner Rover was about
the size of a microwave, Spirit and Opportunity were closer to the size of
golf carts. NASA had essentially just scaled up the six wheel drive Rocker Bogie
system to create these next generation rovers. The extra size and capability allowed the
full collection of scientific instruments from the lander to now be fully mobile for the
first time. In the top of a one point five meters tall mast.
Each rover had nine digital cameras. They were used for both navigation and to
create three dimensional panoramic images of the Martian landscape. The exploration rover also had
its main spectrometer placed on the end of a robotic arm that extended out from
the front for closer examination of rocks and soil. With all of these upgrades
over their predecessor, the twin Rovers were able to accomplish orders of magnitude more
exploration and data collection than any previous Mars mission. The Spirit Rover had a
lifespan of six years and drove four point eight miles, while the Opportunity exceeded
all expectations to last over fourteen years and cover twenty eight miles of the alien
landscape. This is the next generation of Mars rover. You're looking at a
self portrait taken by a robot on the surface of the planet Mars. In
the year twenty twelve, this rover, named Curiosity, became the first of
a new breed of vehicle to roam the Martian surface. Again, we have
to establish a sense of scale here, because this machine is a lot bigger
than most people realize. So here's our microwave sized Sojourner, and here is
our golf cart sized Opportunity. And now we bring in Curiosity. This is
around the size of a crossover suv. It's really big. You'll notice we
have the same six wheel drive powertrain and a much bigger and beefier version of
the same rocker bogie suspension system. At this scale you can really see how
the wheels are linked to the main body of the rover. It's now a
tried and tested method for traversing the jagged, rocky surface. You'll also notice
that, unlike its predecessors, Curiosity does not have solar panels. Instead,
the rover is powered by a radio isotope thermo electric generator. Heat generated by
the radioactive decay of a plutonium isotope is converted into electricity by thermo couples,
and any excess heat not turned into electricity is used to keep the systems warm
during the Martian night. With eleven pounds of plutonium two three eight on board,
Curiosity's generator has a minimum lifespan of fourteen years, and the rover is
still going strong to this day. In twenty twenty one, Curiosity was joined
on Mars by its own twin rover, Perseverance, part of the Mars twenty
twenty mission. Perseverance is mostly the same car sized platform as its older sibling,
just with an upgraded collect of scientific instruments and recording tools. It carries
seven primary payload instruments, nineteen cameras and two microphones. It was the first
time that audio recording equipment had been sent to Mars, and that's how we
know that the wind on the Red planet sounds like this. We can also
hear the sound of the rover itself as the hollow metal wheels clang over the
Martian rocks, the gentle whirring of the electric motors, and the squeaking of
the suspension system. And thanks to a very special payload delivered by Perseverance,
we have this. You are hearing the sound of a helicopter flying on Mars
for the first time, and this is the view from eighty feet above the
Martian surface, just like the Pathfinder back in nineteen ninety six, Mars twenty
twenty brought along one small piece of experimental technology, a helicopter drone named Ingenuity,
hitched a ride in the belly of the rover and was deployed on April
third, twenty twenty one. We've seen NASA make some pretty amazing progress with
their rover vehicles over the twenty five year period that we just covered, but
there is still only so much that can be accomplished on wheels. This is
rugged and uneven terrain. Inevitably you will reach a hill that is too steep
to climb. If we want to take interplanetary exploration to the next level,
we have to learn how to fly. In many ways. Ingenuity was NASA's
biggest risk yet when it comes to tech demonstrations on Mars, because we knew
without any doubt that wheels would work on Mars just as well as they do
on the Earth. But propellers are a whole other story. This is a
DJI Phantom drone. You've probably seen one before, maybe even own one yourself.
It's not so different from NASA's Mars drone. The frame is a comparable
size to Ingenuity. The Dji is a bit smaller overall and about one pound
lighter. Using four tiny propellers, the Phantom can rise thousands of feet in
to the air, while Ingenuity uses two relatively giant propellers with a four foot
wingspan, and with this it achieves a maximum height of around eighty feet.
Ingenuity needs much larger flight hardware to accomplish much less performance because it is flying
in an environment with less than one percent the atmospheric density of the Earth at
sea level. To find an equivalent air density on Earth, you would need
to go to an altitude of eighty seven thousand feet. The highest anyone has
ever flown a helicopter is just over forty thousand feet. In order to test
the helicopter's flight system on Earth, NASA had to use a vacuum chamber that
simulated the low density atmosphere of Mars. They also had to use a cable
system that would pull up on the helicopter at just the right tension to simulate
the reduced gravity effect as well. They even had fans blowing air across the
chamber to try and simulate wind on Mars. Due to do all of these
factors, the propeller system on Ingenuity is very unique. Each blade is shaped
for maximum lift. They are constructed from am ultra lightweight foam with a carbon
fiber reinforced shell. To achieve lift on Mars, the blades need to spin
at doubled rpm that would be required on Earth. The two propellers are counter
rotating to keep the drone stable in flight. A traditional helicopter uses a tail
rotor to do the same job. And a quad copter. Drone uses two
sets of counter rotating propellers on opposing corners. Because of the small size and
high energy requirements, Ingenuity is limited to a maximum of ninety seconds flying time
before it has to stop and recharge. The internal systems of Ingenuity have a
lot in common with a modern smartphone. It uses two sony cameras, half
a dozen sony lithium ion battery cells, a cell phone grade inertial measurement unit,
and a Garmin ultimeter. The batteries are charged by a solar panel mounted
to the top of the drone. With d all of the technology built into
Ingenuity, there was still doubt that a helicopter would be able to perform on
Mars. Even within NASA, there was opposition to the project, and some
top officials thought it was a waste of resources to ship the drone along with
Perseverance. But just like the Sojourner rover before it, the first Mars helicopter
has far exceeded expectations for its performance and longevity. The initial technical demonstration had
only planned for five flights on Mars. Two and a half years later,
Ingenuity has completed sixty seven flights with a total of over two hours flying time.
The helicopter is currently being used as a scouting vehicle to help plan out
the journey of the Perseverance Rover as it navigates the steep river deltas of the
Jezero Crater. The initial success has already begun to fuel new concept ideas at
NASA. The Mars Science Helicopter is a six propeller drone with a mass of
around thirty kilogram. The much larger hexaicopter would be able to fly up to
ten kilometers in one mission and carry up to five kilograms of scientific payloads along
for the flight. If we remember, the Spirit Rover covered just under eight
kilometers in its entire six year lifespan, so to fly further in one day
with the Mars Science Helicopter would be a gigantic leap forward in our exploration of
the Red planet. We know that NASA is also envisioning a pair of Ingenuity
like helicopters for their Mars sample return mission in twenty thirty. As the Perseverance
Rover explores the Jesero Crater, it has been collecting samples from underneath the surface
regolith and leaving them behind in sealed tubes. The idea is that eventually NASA
will follow up to collect the sample tubes and return them to the Earth for
study. The original idea was to use a fetch rover that would essentially retrace
the Perseverance journey and collect the tubes, but with the unexpected success of their
demonstration helicopter, NASA is thinking that flying machines will be much faster and more
efficient for retrieving the samples. And this doesn't end on Mars either. Dragonfly
is a quad copter drone that will fly on Saturn's moon Titan. This is
a surreal world where the frozen surface is covered by flowing rivers and seas of
liquid methane, so alien that it is almost incomprehensible, but the thick nitrogen
atmosphere on Titan makes an ideal location to fly a drone. In many ways,
we're lucky that Mars offers such a challenging environment to practice flying so relatively
close to home, because if we can master the art of flight on Mars,
then the possibilities will be nearly endless.