This is one of the few places in our solar system where we have a
good chance to look for life.
There's evidence for a vast subsurface ocean
below the icy crust of the moon.
The amount of water that is suspected there is many times more
than all the oceans together we have on Earth.
On the poles, you're approaching minus 200 degrees Celsius.
Icicles that could be several metres high might be present.
And if you're very lucky, then you might just spot a plume erupting
nearby, like an ice volcano that ejects material from the subsurface
to enormous altitudes.
On top of that, there's a good chance that there's an energy
source at the bottom of the ocean – hydrothermal activity that can
support the emergence of life.
That makes Europa outstanding.
Europa Clipper is the first mission that goes to the outer
solar system that has the exclusive goal to investigate the
habitability of the body in the outer solar system.
It will launch in October 2024 and will arrive at Jupiter in April 2030.
So it's five and a half years for Europa Clipper.
Jupiter has like about 70 moons, so the number increases like
every year by a bit.
But there are four moons that stand out that are the so-called
Galilean moons.
The innermost is Io, then Europa, then Ganymede and then Callisto.
From the telescopic observations before the arrival of the first
spacecraft, you could see that some of these moons are really,
really bright.
They reflect way more light than a rocky surface would.
And so, for example, Europa and also Enceladus, they are one of the
brightest objects.
And so it was suspected already at that time that the surface might be
composed of shiny reflecting water ice.
I mean, after the investigations of the Galileo spacecraft in the
late '90s, Europa became a prime target in planetary science all
over the solar system because with a huge subsurface ocean,
with expected tidal thermal activity that became the first
place that could be habitable in our solar system
besides maybe Mars. That immediately sparked proposals of
missions to go back to Jupiter and specifically investigate Europa.
I mean, if you are a planetary scientist, probably the most
rewarding science goal is to see if a planetary body is habitable or
actually inhabited.
So Europa Clipper will stay in orbit around Jupiter, and in most of
its revolutions, it will have a close flyby at Europa.
The flybys are arranged in a way that it's like a web at the end
surrounding the moon. You have, in the end, a good overview
over almost the entire surface after these 50 flybys.
During these close flybys,
you get an idea of what is evaporating from the surface of
Europa. And from that, of course, you learn about the makeup, the
composition of the surface.
And this is, of course, specifically true if there's plume
and venting activity.
That's what really would put a smile on my face if we could
measure plume material that's connected to the subsurface ocean
of Europa.
The instrument called SUDA, the SUrface Dust Analyzer,
is the instrument I'm working on.
It measures the composition of tiny grains that are surrounding
Europa, mostly ice grains. And these grains are knocked off the
surface by micrometeoroid impacts. With the SUDA instrument,
we can sample these materials, and with that, we get an idea about the
surface composition.
We could constrain what salts were there in the ocean.
What if there's an alkali, neutral or basic environment, if there's
hydrothermal activity at the bottom of the ocean.
What the organic chemistry inside the ocean has evolved to.
Unfortunately, we currently only have one example of a planetary
body or a moon where life exists.
And so it's really difficult to speculate about the nature of life
elsewhere. If we look for signs of life on an icy moon like Europa,
it's probably the most straightforward to just look for
simple forms of life. If there would be complex civilisations in
these subsurface oceans,
we probably would have known by now, right?
But I know that at least for the life on Earth, access to oxygen
is important to develop complex life compared to simple
monocellular life.
So this is one of the big science questions that Europa Clipper wants
to answer, Has Europa ocean access to oxygen that is created on
the surface? So is material from the surface cycling back down to
the ocean? If yes, then oxygen might be available in the ocean,
and this opens up the possibility for more complex life, not just a
single cell that maybe a fish-like complex life;
everything between one cell or no life or fish-like life, like
complex organisms that might be even intelligent or not.
Nobody knows! It's really up in the air!
I look very much forward to the launch.
It will be launched on Falcon Heavy, that was decided only a few
months ago. So one of Elon Musk's rockets, and I'm very much looking
forward because I never saw a rocket launch in my life.
I like to see it. But on the other hand, it will make me nervous.
So that's always a problem!
Even the safest rockets have a chance of like one percent or two
percent that there's some failure and then everything was in vain
because all the development has been done.
Most instruments have been drafted twice that you have a spare.
I really hope that the launch will go well.
I think it's one of the most exciting missions there is, and I'm
really glad that I can participate in these endeavours.