Nuking Europa, Nukes and other 'futuristic' ideas for exploring Europa Options

[SergeyVLazarev]

Hi all! In my opinion, Europa explorer must be cheap and simple.

It must consist of 5 parts - 2 orbiters, 3 small and robust landers, and 3 nuclear and termonuclear bombs. I think that 10 Kt - 100 kt - 1 Mgt sequence is optimal.


First orbiter is robust, high protected from radioactivity, armed device. On high orbite over Europe
With simple and primitive long focused camera, laser-radar. It must to spectacle and record all nuclear explosion parametres.
has also a radio recever from landers.

second orbiter is orbiting low over the Europe. It must to fly over epicenter of nuke and drop lander to measure and see all.
To defend more complex second orbiter from radioactivity rays of nuclear explosion, we struck and explode a nuke in another side of Europe

Why nukes? Because it reveal all. First one, we"ll have a great quake of Europe. And can record all seismic infomation without landers.
next one. we can to melt ice and see a clear water - just hollow in the crust!!!

at 3 rd.

We dont need a special lander. If we can melt great hollow in crust - we'll have a liquid water to catch our lander! We dont need airbags, rockets. Just an robust "lander" like small susmarine!!

4 th. we ll have great cloud of water vapour and ice to take from there any chemical information.

[dvandorn]

I have to admit, my first reaction to using thermonuclear devices to punch holes in Europa's crust (thereby potentially harming any possible biota within their spheres of destruction) is... well... disgust.

Besides, liquid water wouldn't last for very long up against the vacuum of space that exists at the surface. An ice crust would develop awfully quickly -- you'd still need a way to punch through it with your submarine. Granted, it would be thinner than the natural crust, but it would still propose an obstacle.

Finally, the ice crust seems to be kilometers thick in most places. Just how deep of a hole you think you can dig with a nuclear weapon? Especially one that explodes above the surface? If you want maximum penetration from your nuclear hole, you'll need to bury the weapon about half as deep as the hole you want to make (the "hole" being a spherical void that would be vaporized by the blast and shock effects). That leads you back to ways of drilling or melting down into the crust to place your bomb.

All in all, while it's not the worst idea in the world, I think you'd need to work out all of these details before seriously proposing it...

-the other Doug

[SergeyVLazarev]

I know, that my proposition is sounds like provocation, but is not provocation. :-)

Besides, liquid water wouldn't last for very long up against the vacuum of space that exists at the surface.  An ice crust would develop awfully quickly -- you'd still need a way to punch through it with your submarine.  Granted, it would be thinner than the natural crust, but it would still propose an obstacle.

I dont know how thick may be new ice crust, and you also. :-) thin ice is not a such problem.

Finally, the ice crust seems to be kilometers thick in most places.  Just how deep of a hole you think you can dig with a nuclear weapon?  Especially one that explodes above the surface?

I can place up bombs sequentally. One by one. If crust kilometers thick, in closest 100 years we cant look in that ocean. Just forget this.
If we"ll use bombs to measure thick of ice crust it - its better for us to know that now. and forget europa ocean.

If you want maximum penetration from your nuclear hole, you'll need to bury the weapon about half as deep as the hole you want to make (the "hole" being a spherical void that would be vaporized by the blast and shock effects).  That leads you back to ways of drilling or melting down into the crust to place your bomb.

we can explode bombs one by one. hot water quckly melts ice and weakens its structure.

All in all, while it's not the worst idea in the world, I think you'd need to work out all of these details before seriously proposing it...

I dont know how it serious, but now I cant see another way.

[helvick]

Sergey,

Dramatic idea but it is too complex and you'll need a lot more much bigger bombs. No single nuke built to date has the sort of yield you'd need and the 1 megaton crackers they build these days would barely scratch the surface.

LPL's Crater impact calculator gives some handy ballpark figures for the amount of energy you'll need to be able to deliver to blast your way through.

Taking as an example a very small compact cometary fragment (50m diameter) hitting Europa at 45km/sec (probably a bit high as this is cometary velocity range at Mars orbit), the impact energy is ~15 Megatons. Crater diameter is 2.6km+- a km. Depth will be half that at most.
That's about the same energy as that of the highest yielding nuke the US has tested to date - Castle\Bravo at Bikini in 1954 see here. The USSR's Tsar Bomba yielded 50Megatons however that only adds about half a kilometer to the diameter.

The current estimates I've seen range from 10-40km. At best you'd need to deliver five or six Castle\Bravo class nukes with each successive "probe" requiring pretty awesone precision in order to "tunnel" down. If you just shotgun the surface you'll waste the energy, you'd have to deliver them to the bottom of the crater and as Doug pointed out you'd actually have to penetrate the surface in order to excavate any noticable amount.

It would be easier if you simply redirected a suitable comet. Trying out some numbers I reckon you'd need to find a 3km diameter comet. That would create a 60-100km crater that would probably punch through even a 40km Ice sheet. The energy involved is 3.4 million megatons give or take.

However since the point of the exercise would be to find life this would seem a bit silly since it would not only sterilise but would vapourise anything we were looking for.

And the Europans would be mightily upset.

[SergeyVLazarev]

The current estimates I've seen range from 10-40km. At best you'd need to deliver five or six Castle\Bravo class nukes with each successive "probe" requiring pretty awesone precision in order to "tunnel" down. If you just shotgun the surface you'll waste the energy, you'd have to deliver them to the bottom of the crater and as Doug pointed out you'd actually have to penetrate the surface in order to excavate any noticable amount.

I think that ice is not homogene, but mixed with water filled volumes. water practically unpressured liquid and wiil destroy some structure of ice.
Also ice can cracks.

[helvick]

I think that ice is not homogene, but mixed with water filled volumes. water practically unpressured liquid and wiil destroy some structure of ice.
Also ice can cracks.

Not really. Ice can crack but it's actually a remarkably resilient mineral when you have to deal with it on the scale of mountains. The surface of Europa probably has a structure not dissimilar to Icebergs. The US Navy discovered this when they tested the idea of blowing up Icebergs to test if it was possible to destroy bergs threatening shipping lanes. They came to the conclusion fairly quickly that they'd need much bigger guns and gave up. This pdf about Icebergs closes with this comment:

Both crater blasting and bench blasting have been attempted. The results of this testing suggest that ice is as dificult to blast as typical hard rock, and that therefore the use of explosives for its destruction is impractical.

My emphasis.

Some bright folks have already done some research into this needless to mention. This Lunar and Planetary Institute page shows why they believe the crust is 19-25km deep. Crater formations on Europa demonstrate a morphological change when they exceed +- 30km diameter. Smaller craters follow the usual form expected for impacts into a solid structure, above that diameter something affects the structure and the hypothesis is that it is the crustal depth which would become relevant with craters around 30km diameter for 19km deep crust. That changes the size of my comet excavator a bit, reducing it to 1.25km diameter with a resulting yield of a quarter of a million megatons.

Still 5 orders of magnitude higher than the handful of megatons you proposed. The comet would be neat but since it would weigh ~1.3billion tons and is moving at 45km/sec it would be hard to steer.

Also to return to Doug's point. A surface\air blast will excavate very little. You need to bury your bombs. The first one you could possibly just send in any old how and hope for the best but the subsequent ones would have to come in vertically, that would be require lots of fuel and some very fancy flying.
This document states that approximately 16% of a surface blast goes into cratering\ground shock etc. It also lists some numbers for the destruction depth effects - the maximum depth of destruction for a 9Megaton surface detonation is ~180m.

You really are going to need bigger bombs.