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Lecture 4.13: Exploring Europa
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Del curso dictado por Caltech
The Science of the Solar System
310 calificaciones
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De la lección
Unit 4: Life in the solar system and beyond (week 2)
Conoce a los instructores
Mike BrownProfessor
Planetary Astronomy
Okay, so what's next for exploration of these worlds?
Well in the course of the next few minutes or so we're going to take a little
trip up to Alaska to see some cool robotic stuff that we're doing up there.
That system is hopefully an early precursor to
what someday may go to a world like Europa.
And we'll close with a little bit about sort of the Dream of Dream missions and
then we'll come back down to what's really in the pipeline for the next decade or so.
So heading up to Alaska my team's working up in the far
north slope of Alaska in these permafrost lakes some
10,000 of which dot that landscape.
During the summer these lakes are open to the atmosphere,
during the winter they freeze over.
And some of these lakes have methane bubbling out of them.
And so our team is looking at all sorts of different dynamics with
microbial ecology and the limnology.
But one of the things that's interesting is that some of these lakes actually have
a lot of methane coming out them.
Here you see a methane seep that we lit on fire.
Those bubbles there are all trapped methane, so you can crack them open and
light them on fire.
In some cases, it's a lot of methane and
you actually have to be kind of careful when you light these on fire.
Now I'm not going into a lot of the science that we're doing up there but
I just want to highlight one of the cool engineering technologies that
we've developed and deployed up there.
The basic idea was, we want a submersible but
we don't want the engineering expense of a submersible.
A submersible has thrusters, and those use up a lot of battery power.
And there's all sorts of challenges with providing enough
energy to maintain the submersible as it swims around.
Thankfully, being up at JPL,
I get to work with a lot of the brilliant engineers who design robots like this.
And we kind of had this collective aha of, why don't we build a rover that
floats on the underside of the ice, and can just crawl around.
And when it wants to stop, it can just stop and
not use any battery power other than what we need to take pictures.
So this is what our second-generation prototype looks like.
And I'll load up a little video here and
show you what what happened in the field.
[NOISE] So this is our team going across the Alaskan
permafrost out towards the lakes where we were
testing our buoyant rover for under ice exploration.
From a design stand point, I wanted a small system that was robust to
the shaking and vibration of going across the Alaska permafrost,
that's got the added perk of someday of something like this ends up on a rocket.
It will at least have some vetting for vibration testing.
Here's John Lickty testing our rover on tether and just doing the subsystems
check, making sure the wheels work, rotating the different modules.
And so here the rover is actually positively buoyant
pushing up against that ice.
And we're able to look down and examine the floor and
look at different areas where the methane was coming out.
Here we're out on one of these vigorous methane seeping lakes.
My colleagues there are testing the ice thickness.
Around this time of year, which was October, late October, early November,
the ice is just starting to form in these regions that have got methane seeping out,
and you can see a few open areas there.
Little bubbles coming out, It's not hot.
It's just the kinetic activity of the methane seeping that
causes this open water to stay open.
And as we scan over to the right here to where I'm standing,
you'll see that I'm actually on very thin ice, and
the methane is bubbling out very vigorously, as you can see there.
Now we'll go under the ice, but this time the rover is untethered and
our team was able to operate the rover via satellite
link from our warm Kwanzaa hut in Barrow, Alaska.
And the guys were also able to hand over control to some of the engineers back
at JPL.
So we think this is the first time ever that an underwater, under-ice, untethered,
satellite operated vehicle has successfully been deployed.
We left it out there for two separate periods of 30
hours each and covered tens of meters or so of mapping.
In the future, we hope to leave it out there for weeks and eventually for
the entire field season.
So we deploy in October, come back in the Spring and pick it up.
So now you get to see what it look like from the rover perspective.
Here you are, rover vision.
Beautiful sunny Alaska morning,
we'll drive over to this hole in the ice and drop on in.
Now we're driving along on the underside of the ice and
you can see these, what look like pools of mercury but
that's really methane gas that's trapped under the ice.
And as we control the cameras and
look around you can see some of the methane seeping out.
You can also see these white regions that we think are vegeotoa and
some other microbial communities.
And so along with cameras we also have an instrument suite
on the tail of the rover that allows us to map out things like Methane and
oxygen and pH and conductivity.
So this is kind of the very primitive form of something that we would love to someday
send to Europa or Enceladus, what would the real system actually look like?
Well let's take a look at that.
So this is the dream of dreams mission.
And credit for this goes to James Cameron and Disney and this is an excerpt from
the Aliens of the deep IMAX film of which I was a part of over a decade ago.
And in this we envisioned coming in to Europa with a highly capable
robotic vehicle that could navigate.
The terrain of Europa, find a nice flat spot, and then once
it landed it would have to deploy a melt probe, this would be nuclear powered or
you could envision large solar arrays getting deployed to pipe energy down.
It melts through the ice, leaving behind a communication's teller.
And once it reaches the ocean, it deploys the nose cone and
out pops this autonomous under water vehicle.
Now of course the autonomy here is key this thing would have to have a lot
of artificial intelligence there's no way you're joy sticking this from the ground.
And then this vehicle would go down to the bottom of the ocean hopefully,
and in at least the Hollywood version the autonomous under water vehicle
finds hydrothermal events.
Along with large charismatic looking alien creatures in the bottom of Europa's ocean.
That is the dream of dreams, this particular mission is
decades off, but the fact of the matter is that the technology is actually
not that hard to envision given what we have available today.
So scaling back from the melt probe full ocean exploration mission,
what's actually going to happen next?
What do we have in the relatively near term pipeline?
Well, the European Space Agency has got a mission called
the Jupiter Icy Moons Explorer or Juice.
And this is a mission that is being built now, and
it will hit the launch pad in the 2022 or so time frame and
arrive in the Jovian System around 2030.
It will make two fly bars of Europa, a few fly bars of and Ganymede.
And the go into orbit around Ganymede and map and
investigate that world in great detail.
On the NASA side we've go the Europa Clipper mission that has been studied in
great detail and is not yet at, what is called Phase A.
It doesn't have the full green light from headquarters yet but
it's at a point where we're optimistic that a mission like this
will go forward and start to be built within the next few years.
Hopefully, getting to the launch pad around 2022 also.
Now an interesting aspect of what happens on the launch pad and
after launch pad is that, the rocket that you use gets you to
Jupiter either in six to seven years or less than three years.
Right now, JPL and NASA are looking at a couple of different options.
One is you use a rocket like a Delta Four Heavy or
an Atlas Five Five One, and you do a Venus, Earth, Earth gravity assist.
Which gets you out to Jupiter in about six to seven years.
If however, we use the space launch system which is being built by
the Human Exploration Mission then we could get
the Europa Clipper mission out to Jupiter in about 2.7 years.
That's obviously quite attractive.
Get it out there much faster, get our data back sooner.
Another component of this that's interesting is that we can actually trade
a little bit of that time to add more mass to the mission.
And potentially carry at least a simplified lander that might go down to
the surface and investigate the chemistry with capabilities.
The Clipper mission as currently designed would orbit Jupiter and
make some 45 or so flybys of Europa.
And those flybys are shown here by these little sticks around Europa.
And as the spacecraft flies by Europa, it'll take images,
spectra to get the composition, and
utilize ice-penetrating radar to look for liquid water pockets in the ice.
And also to hopefully map the ocean ice interface within Europa.
So that's what's next, we've got hopefully the Europa Clipper mission
we definitely have the European Space Agency Juice mission.
And somewhere down the line we'll get that melt probe to the surface and
melt through the ice to investigate the ocean directly.
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