Outside of earth Europa is probably the best place for life as we know it to develop. Beneath the radiation soaked exterior, which consists of an ice layer that could be up to 20KM thick, lies a vast ocean that stretches deep into Europa’s interior. This internal ocean, though bereft of any light, could very well harbor the right conditions to support the development of complex life. However if we’re ever going to entertain the idea of exploring the depths of that vast and dark place we’ll first need a lot more data on Europa itself. Last week NASA has greenlit the Europa Clipper mission which will do just that, slated for some time in the 2020 decade.
Exploration of Europa has been relatively sparse, with the most recent mission being the New Horizons probe which imaged Europa on its Jupiter flyby on its path to Pluto. Indeed the majority of missions that have imaged Europa have been flybys with the only long duration mission being the Galileo probe that was in orbit around Jupiter for 8 years which included numerous flybys of Europa. The Europa Clipper mission would be quite similar in nature with the craft conducting multiple flybys rather than staying in orbit. The mission would include the multiple year journey to our jovian brother and no less than 45 flybys of Europa once it arrived.
It might seem odd that an observation mission would opt to do numerous flybys rather than a continuous orbit however there are multiple reasons for this. For starters Jupiter has a powerful radiation belt that stretches some 700,000KM out from the planet, enveloping Europa. This means that any craft that dares enter Jupiter’s orbit its lifetime is usually somewhat limited and should NASA have opted for an orbital mission rather than a flyby one the craft’s expected lifetime wouldn’t be much more than a month or so. Strictly speaking this might not be too much of an issue as you can make a lot of observations in a month however the real challenge comes from getting that data back down to Earth.
Deep space robotic probes are often capable of capturing a lot more information than they’re able to send back in real time, leading to them storing a lot of information locally and transmitting it back over a longer period of time. If the Europa clipper was orbital this would mean it would only have 30 days with which to send back information, not nearly enough for the volumes of data that modern probes can generate. The flybys though give the probe more than enough time to dump all of its data back down to Earth whilst it’s coasting outside of Jupiter’s harsh radiation belts, ensuring that all data gathered is returned safely.
Hopefully the data that this craft brings back will pave the way for a potential mission to the surface sometime in the future. Europa has so much potential for harboring life that we simply must investigate it and the data gleaned from the Europa Clipper mission will provide the basis for a future landing mission. Of course such a mission is likely decades away however I, and many others, believe that a mission to poke beneath the surface of Europa is the best chance we have of finding alien life. Even if we don’t that will provide valuable insight into the conditions for forming life and will help point our future searches.
If there’s any place in our solar system that we’d want to start seriously looking for life it’d be Europa. The dust covered snowball of a moon likely contains a vast subsurface ocean, one that is kept liquid by the giant gravitational forces of its host planet Jupiter. This makes Europa a great candidate for life as we know it as once we find water it’s inevitable that we find life shortly thereafter. The challenge with Europa though is getting to that subsurface ocean to study it as it could be covered in several kilometers of water ice, not something you can simply puncture through. Whilst there are numerous people more qualified than me on this subject, many of them actually working in the aerospace industry, with NASA asking for ideas for a potential mission to Europa I figured I’d throw my 2 cents in.
So the total budget for the potential mission is a cool $1 billion and whilst that sounds like a lot of money projects that I’d consider simpler than my idea (like say Curiosity which was $2.5 billion) but I think there’s potential to build a platform that could fuel further missions. With that in mind this initial mission is likely only to be a scouting mission, one that will give us the most detailed picture of Europa possible so that the follow up mission can choose the perfect site to land on and commence the search for life in its vast underground ocean. My proposal then is to develop a compact nuclear reactor (not a RTG) to power a scouting craft laden with instruments to analyse the gravitic field and surface of Europa. This craft will be able to find the point at which the surface ice is the thinnest and identify potential landing sites for the second generation craft: a cryobot that will punch through to the ocean below.
Putting a nuclear reactor into space might sound like the plan of a crazed sci-fi nerd but there’s actually been dozens of small prototype reactors launched into space with all of them proving to be safe and reliable. The power capabilities of such a reactor are far beyond that of what a small satellite would usually require however attempting to melt through kilometers of ice will require power of that scale. Thus it would make sense to fund research into developing the power supply first and then validating it on the scouting craft. Then, once that mission is successful, the reactor can be scaled to the appropriate dimensions for the cryobot mission and even used in other deep space programs.
Having such a generous amount of power available also opens up the opportunity to using instruments on the scouting craft which would not be feasible, typically. Things like high-power antennas (which could function as a relay for the follow up mission), radar imagers or bigger and better versions of other instruments. My knowledge on the power requirements of various instruments is limited but I know that even the most advanced RTGs, like the one in Curiosity, produce a measly 125W. Being able to draw on several kilowatts, an order of magnitude more power, seems like it would open up many opportunities that just weren’t possible previously.
I’m probably vastly underestimating how much it would cost to develop such technology, especially in today’s nuclear hostile political environment, but if we’re serious about actually digging under Europa’s surface I don’t see what our other options would be. Melting through giant sheets of ice is no small task and one that has requirements that far surpass anything we have currently. Using that $1 billion mission to set ourselves up for future exploration seems like the best bet especially considering how many other applications a safe, small nuclear reactor would have.
Carl Sagan is quote as saying that “life looks for life”. Indeed if our own history is anything to go by we’re in a constant state of searching out other forms of life and just recently we’ve extended that search beyond the confines of the world that gave rise to us. So far our search beyond our home world has proved fruitless as we’ve been unable to find any direct indications of life on any other heavenly body that’s within our reach. Thus we find Earth in what appears to be some great isolation which is a somewhat disconcerting notion given the age of the universe and the number of potential habitable planets in our galactic backyard. We should not be discouraged however as our quest to find life elsewhere is only just beginning.
Of all the other heavenly bodies that inhabit our solar system there’s one that stands out as the best candidate for housing life. Now if I was to ask the question of which body it was most people would respond with Mars as it’s the only planet that resembles Earth in some fashion, with the next closest candidate being the raging hell of Venus. It’s not a bad guess either as we’ve proven several times over that there was once vast amounts of water there and there’s still a very good chance there’s liquid water present today. However Mars is a very inhospitable place so much so that the best hope for life there is nothing above microbial and even that seems like a far reaching prospect.
Europa on the other hand is quite the curiosity. As far as moons go it really is something out of left field being a striking combination of bright whites and browns. It’s surface is also one of the smoothest in the solar system thanks to it being made almost entirely of water ice. That doesn’t mean it’s featureless however as the entire surface is criss-crossed with fracture lines from the giant ice sheet breaking apart and reforming. Many have speculated that this is because the surface actually lies on top of a giant subsurface ocean and when cracks form the ocean rushes up to fill it, forming the characteristic lines. It’s this undersea ocean that makes Europa one of the best candidates for life forming outside of Earth and recent studies show it just got a little better.
The potential ocean on Europa would be some 3KM below the surface, quite a ways away from any direct sunlight or other potential energy sources. It’s theorized then that the ocean is kept liquid by the tidal flexing that Europa undergoes every time it orbits Jupiter which could also drive the same kinds of volcanism processes that gives rise to life in the depths of our oceans. However recent research shows that there’s potential for some subsurface lakes that are much closer to the surface than the great ocean below. These lakes would have a higher rate of churn between water and ice providing a much a habitat that’d be more nutrient rich and hopefully more hospitable to life. Of both these recently modelled oceans and the great subsurface ocean haven’t yet been conclusively proven, but that just makes Europa a really tantalizing target for exploration.
Quite a few missions have swung past Europa already with the most detailed analysis being done by the Galileo craft from 1995 to 2003. However we haven’t been back there recently save for a short flyby by the New Horizons craft that imaged it on its way to Pluto. If we were to go back there my favourite mission candidate would be the Crybot style mission. In essence it’s a probe that’s fitted with a giant heater on the front of it, capable of plunging through several kilometres of ice. Once it broke through it would then deploy a small autonomous underwater vehicle that could investigate the subsurface ocean. This mission hasn’t got past the back of the napkin style planning stages yet, but I’m hopeful that we’ll one day attempt such a mission.
Europa is a curiosity unlike any other in our solar system and there’s so much we could learn from it if we were to send a mission there. Whilst the environment there isn’t really human friendly (the radiation at the surface is quite large, about 450 chest x-rays a day worth) it’s definitely within our current capabilities of robotic exploration. I know that one day we’ll see a dedicate mission there but until then I’m quite content to continue fantasizing about the undersea world that it contains and the tantalizing possibility that as of yet unknown life forms exist there.
Life is a tricky thing to get right. As far as we know right now we’re a completely unique in this universe and the conditions that led to us being here are both mysterious and endlessly intriguing. Whilst I won’t dive into the debate on science vs religion here (I’ve already done that) my own personal views are ones of abiogenesis, or more simply the idea that the complex life that we know and love today arose from a long chain of events that started with just the basic elements of the universe. Whilst there’s still a lack of consensus around the actual mechanisms that would have led to this happening the basic idea remains the same.
This is mostly due to the lack of another point of data, I.E. us encountering life that arose on another planet. So instead we start looking around our own earth to find examples of how life got started and where it exists. We’re discovering more and more that environments that we thought were completely incompatible with life are actually teaming with creatures that seem almost impossible to us. From complex curiosities like the Yeti Crab and the Flashlight Fish to bacteria that thrive on the heat radiated from black smokers it seems that once conditions are favourable to life you’ll end up finding it pretty much anywhere.
Still there are some places you just don’t expect to find life, like 185 meters below an ice sheet:
Researchers in Antarctica got a surprise visit from a creature in a borehole 185 meters (600 feet) below the Antarctic ice, where there is usually no light. A Lyssianasid amphipod, a shrimp-like creature can be seen swimming in this video. A NASA team had lowered a small video camera to get the first-ever photograph of the underside of an ice shelf when the curious little 7 cm (3- inch) shrimp stopped by to check out the equipment. Scientists say this could challenge the idea of where and how forms of life can survive. Anyone else thinking Europa?
To say that little shrimp was completely unexpected would be putting it lightly as for all we knew there was absolutely nothing down there capable of supporting life any larger than simple bacteria. They also found what appears to be the tentacle of a jellyfish tangle around the cord of the camera suggesting there’s not only life but also some amount of diversity down there. So whilst this might be cool and all why is everyone asking about Europa?
For those of you not in the know Europa is a moon of the planet Jupiter and is only a bit smaller than our very own Moon. It’s quite a striking thing to look at as it’s surface looks like a round ice cube that’s covered in dust, very different to our closest neighbour who’s an even shade of dull gray. When we get up and close to it we see it’s covered in these long lines which look scarily similar to ice sheets on earth. As it turns out Europa’s crust is actually a solid layer of ice that’s a few kilometers thick and under that is an internal ocean that, as our best guess goes, is tens of kilometers deep. The lines on the surface are cracks that opened up to the internal ocean below where upon water from below swelled up to fill the gap.
What the scientists’ unexpected visitor tells us is that there is the possibility for complex life to evolve in places where light cannot reach it, and that means that there’s a chance that life evolved in the sea under Europa.
You may be wondering how life could evolve in a place that’s covered by kilometers of ice in a frigid sea so far from the sun. Well as it turns out thanks to its giant parent planet and slightly non-circular orbit Europa is constantly being squeezed and pulled every time it completes one round trip. This has the effect of creating an extreme amount of internal heat that not only serves to keep the internal ocean liquid but could also serve to generate the volcanism that some theories believe is required to create life. Out of all the other places in the solar system this is probably the only other place where life could potentially exist based on the evidence we’ve gathered here on earth.
It’s discoveries like this that get me all excited about the infinite possibilities of the universe. Whilst there’s no evidence that there are any other intelligent life forms out there the evidence is getting stronger and stronger that it’s there, we just have to go and find it. I know that one day we’ll send a probe to Europa to see what is really under that thick ice blanket and should we find life there you can bet your bottom dollar that it will change how we view ourselves and our place in the universe forever.