Original subtitles

(ominous music)

- [Rosaly] Venus is really a hellish place.

- [Geoff] The surface temperature is 450 degrees.

None of our electronics will work.

- [Tony] You try to put something on the surface of Venus,

and it's destroyed in a few minutes.

(ominous music intensifies)

- Venus has the densest atmosphere

of all the solid bodies in the solar system.

Venus' surface temperature is hotter even than Mercury's,

and Mercury's closer to the sun.

It's because of this atmosphere

that really keeps the heat in.

- The surface of Venus is a ferocious place.

It is 90 times the atmospheric pressure of the Earth.

That's like the pressure of one kilometer under the ocean.

But a temperature of 450 celsius,

that's like the temperature of your oven

when you're running the self-clean cycle.

(thunder rumbling)

- The surface of Venus is hot enough to melt lead,

so it is about as miserable looking

and miserable feeling a place

as you could imagine experiencing

if you could stand on the surface.

- You would feel very sluggish.

You would not move very quickly,

and if a gust of wind came it would be very powerful.

It could knock you over.

It would also be very dim because it only receives

about 3% of the incident sunlight

that it receives at the top of the atmosphere,

because the atmosphere is so thick,

a bit reddish, we believe,

from the Venera probes and the Vega probes

that went to the surface and took pictures of it.

- How do you make a power system

for the surface of Venus?

That turns out to be hard.

Not only is it hot, but it's cloudy.

There's not much solar energy.

- Venus does have some solar power on the surface,

although it's a fraction of what is available

here on Earth is actually available on the surface of Venus

due to the thick cloud layers,

due to also the red shifting of the light,

and that solar panels don't work as efficiently.

The other big challenge with using solar on Venus

is that Venus has a very long night, about 60 days.

You would have to go 60 Earth days, that is, without power.

Therefore, one of the places we're looking to get energy

is from the wind.

Venus has a very thick atmosphere.

Collect that with a wind turbine

and then directly transfer that

to the wheels to drive you at low speed, high torque.

- Could we perhaps make a rover that has a sail,

so the sail propels it across the surface?

The Venus land sailer concept that we have

is a mission design we made called the Zephyr

that sails on the surface of Venus

instead of running on a motor.

We can make the sail out of a silica-woven,

fiberglass-like sheet,

and we think that we can make high-temperature materials

that can operate on the surface.

The worst problem we have here

is that none of our electronics will work.

The longest-lived probe for the surface of Venus

has been just a little over two hours,

and that's the time it takes for the heat to soak in

and begin to destroy the electronics.

So we don't use conventional silicon.

We use a new semiconductor called silicon carbide

that can operate at these temperatures.

- Well, vacuum tube and vacuum tube-based

electronic approaches actually work really well

at high temperatures, unlike modern systems on a chip.

The problem with that, though, is the high pressure

makes it challenging to maintain that vacuum

for an extended duration.

And how you do a rover that's much simpler and more basic

than what your current rovers are for Mars

because of the limitations of those electronics,

we sort of took a look back and thought

what would it look like if we were designing a rover

but designing it back in the 40s or 50s?

What if we just throw all the electronics off the spread,

just make the whole thing mechanical?

Make it all "Strandbeests" like Theo Jansen's "Strandbeests"

or all steampunk, or even go back

to the Antikythera mechanism,

which is a mechanical computer

that the Greeks developed

in about 200 B.C. or so,

what would you end up getting?

How do we do not just the rover drive system mechanically

but let's make all our measurements mechanical as well,

like sort of an old clock spring-style thermostat?

So this is a clock that is fully made

out of stainless steel.

It's been baked out at 460 degrees Celsius

and has been operated in an oven.

If we build everything out of off-the-shelf

300 series stainless steel,

the coefficient of thermal expansion

would be close enough that even when you're going

to extreme temperatures like Venus,

the entire assembly would just expand

and contract together, and you wouldn't get jamming.

And by using graphalloy bushings

at each of the bearing surfaces,

we could actually get it to run

at Venus conditions.

(metal ticking)

(gentle music)

- So far, the electronics that we can make on Venus

are not as sophisticated as the electronics

you can make on Earth.

We can make very simple calculators

but we can't make whole computers.

So right now, when we talk about systems

that can land on Venus, we have the sensors on the surface,

we have the radio on the surface,

but most of the processing power,

most of the computers, most of the things

that run the mission would be high overhead.

We could either put them perhaps in an airplane

that's flying 50 kilometers above

or maybe in a satellite,

and it controls the probe on the surface,

almost like you would be controlling

a radio-controlled car.

We could send a probe to Venus

that would be an airplane,

not just a balloon floating passively

in the atmosphere of Venus,

but we want to make a solar-powered airplane.

And a solar-powered airplane

in principle could fly forever,

as long as we can fly faster than that wind

so we can stay in the sunlight.

(propellers flapping in wind)

- If we could get an aircraft to Venus,

it will fly, especially if it's

semi-buoyant so that when it gets to the night side

it can just glide and not sink down to the surface.

And when the time comes it may sink down to the surface

and we might get a profile all the way down to the planet.

Some folks at Northrop Grumman

have designed a concept which is a semi-buoyant airplane.

It's called a Venus Atmospheric Maneuverable Platform.

And that could survive for a few months.

It's solar powered, it's filled

with a light gas, either hydrogen, helium.

You can have solar panels on the top and the bottom

because when you're in the middle of the clouds

there's so much light scattering that

it doesn't matter where you collect

the solar energy from because it's very diffused.

- Oh off in the clouds of Venus

is actually a great place to be.

If you're at about 50 kilometers or so above the surface

your temperature and your pressure

are very similar to what it is here on Earth.

In fact, it's probably the most Earth-like place

in the solar system.

However, there is sulfuric-acid rain

that you have to deal with,

but with the proper coatings,

you can deal with that.

Personally, I love the idea

of a human-crewed mission

to a cloud-city on Venus

and love the idea that you would just need to wear

some type of suit that would provide you

with oxygen to breathe as well as also

a protection from the chemical air,

but you wouldn't necessarily need a pressure suit as well.

That being said, humans tend to not like the idea

of not being able to be on firm ground,

and the idea that you have to stay floating

above the clouds, above this furnace, essentially,

in some ways is a hard sell.

The other key challenge that we have with Venus

is how to return to orbit

and basically get back off the planet,

as you don't have a large launch infrastructure

that you could use so you have to look at another approach

for getting back out of Venus orbit.

(majestic orchestral music)