Author Topic: Asteroid Impact Shelters Using Deep Sea Stations  (Read 2002 times)

Offline Mr. Scott

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Asteroid Impact Shelters Using Deep Sea Stations
« on: 08/05/2017 04:06 AM »
Last year, China is said to have announced their plans to develop deep sea stations at a depth of 10,000 ft within the ocean.  Their interest is to develop the tehnologies that enable this first in order to take advantage of resources of the deep sea.

Could a deep sea station be an effective shelter for a large colony of humans from an asteroid impact or other natural disasters?  Is this a more effective approach than attempting to detect, deflect and/or destroy Chicxulub class asteroids?

What other benefits from the technology would a self sustaining/colonized deep sea station provide?  Does this align with human space flight technologies such as human exploration, power generation, ISRU, advanced transportation vehicle development?  Is this a government only development project, commercial project or merely only a paper piñata?  If the US developed similar technology, would this require funding greater than NASA's current annual
budget annually?

I prefer lively debate and less moderation. I will award points before January 1st 2018 for thought leadership.

http://www.tslug.com/wp-content/uploads/2016/06/Deep-Sea-South-CHina-Sea-Lab.png
« Last Edit: 08/05/2017 04:24 AM by Mr. Scott »

Offline Archibald

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Re: Asteroid Impact Shelters Using Deep Sea Stations
« Reply #1 on: 08/05/2017 09:25 AM »
Hmmm... if the asteroid falls into the ocean near your shelter, you are toast. Also the tidal wave.

Now that's an interesting question. Does anybody knows if the bottom of the Mariana trench would be affected by a Chicxulub ?

(that was my 2000th post on this forum  8)   )
« Last Edit: 08/05/2017 06:42 PM by Archibald »

Offline Hog

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Re: Asteroid Impact Shelters Using Deep Sea Stations
« Reply #2 on: 08/05/2017 10:59 AM »
The Chicxulub impactor delivered an estimated energy of 10 billion Hiroshima A-bombs.

The asteroid linked to the extinction of dinosaurs, which created the Chicxulub crater in Yucatán approximately 66 million years ago, would have caused an over 100 metres (330 ft) tall megatsunami. The height of the tsunami was limited due to relatively shallow sea in the area of the impact; in deep sea it would be 4.6 kilometres (2.9 mi) tall.

The lack of compressibility of liquids would make for a heck of a shockwave to any submerged structure with any sort of closer range. Surviving the impact and its immediate effects are one thing, surviving the "nuclear Winter" is another.  No matter what we as humans do, once the Sun's radiation is blocked from entering the Earths atmosphere for any appreciable amount of time, it's curtains for the human race.



That Castle Bravo shot and its 15,000,000 tonnes of TNT equivalency bring dust/debris up to altitudes of 30,000 feet.  Just imagine what a blast with 10,000,000,000 (10 billion) Hiroshima sized 15,000 tonne TNT equivalency would do? 
That blast would be the equivalent TNT yield of 1,500,000,000,000,000 or One Quadrillion, 500 trillion tonnes of Trinitrotoluene. That much TNT would fill 12,500,000,000,000 or 12 trillion 400 billion railroad boxcars.  With 120 tonnes of TNT in each rail car, the train length excluding hitch connections or locomotives would be  140,909,090,909 miles or 226,771,199,999 kilometers long.  That train would circle the Earth at its equator 5,658,669 times.
 In other words, the Chicxulub impactor contained a LOT of energy.

Pic#1 Here is a diagram that shows atomic detonations and how their yield relates to how the bring dust/debris into the atmosphere.
« Last Edit: 08/05/2017 11:15 AM by Hog »
Paul

Offline eric z

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Re: Asteroid Impact Shelters Using Deep Sea Stations
« Reply #3 on: 08/05/2017 11:27 AM »
 Isn't that a picture from J-YC's Conshelf program? If not, it looks Very similar to one I remember from growing up. ??? Time to get out the old "National Geographic" mags!
« Last Edit: 08/05/2017 05:35 PM by eric z »

Offline meberbs

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Re: Asteroid Impact Shelters Using Deep Sea Stations
« Reply #4 on: 08/05/2017 02:40 PM »
Unless there is a direct impact at every deep water station placed around the world, then you just wait out the after effects or remediate then. 
If you ignore the billions who wouldn't fit in a shelter, and the lack of any more supplies received from the surface.

So there is some evidence that extinction events are survivable.  Technology is a capability that enables you to do something.  Other than colonizing Mars, what technologies enable you to survive a 10+km diameter asteroid impact?
To start with: detecting it a few decades in advance and sending a gravity tractor to nudge it out of the way.

Offline Coastal Ron

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Re: Asteroid Impact Shelters Using Deep Sea Stations
« Reply #5 on: 08/05/2017 03:20 PM »
Could a deep sea station be an effective shelter for a large colony of humans from an asteroid impact or other natural disasters?

No. Besides the amount of mass needed to build pressure vessels large enough and strong enough for a "large colony" of humans, I would think that if an asteroid hit the ocean that it would crush such structures.

If you want to bury the human race to protect them from the effects of an asteroid, it's better to do it on land.
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Offline meberbs

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Re: Asteroid Impact Shelters Using Deep Sea Stations
« Reply #6 on: 08/05/2017 03:24 PM »
I guess the original topic is about an assumption that deflecting the asteroids is simply more difficult than just trying to survive using a shelter.  If you see a clear simpler path to deflect a 10+ km diameter asteroid, that is certainly welcome info...

What I'm trying to get a sense of is, is this concept (originating from China) slightly more feasible than a large colonization of mars with billions of people?
Relocating billions of people underwater or to Mars are both infeasible especially when compared with:
detecting it a few decades in advance and sending a gravity tractor to nudge it out of the way.

Online ThinkerX

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Re: Asteroid Impact Shelters Using Deep Sea Stations
« Reply #7 on: 08/05/2017 05:51 PM »
Quote
What if a deep sea station was built in a deep lake surrounded by land structures?  This way if a global tsunami were to be initiated, the lake would be protected by:

1) depth and
2) breadth of land

Yes, pressure vessels do buckle.  So the design, geometry and construction would need to be intricate.  There may be a way to do this modularly.

Just trying to form the initial thoughts for the thread... going to hit autopilot for now.

This is not my original idea.  Just taking the viewpoint and attempting to form some basis of argument to see where it begins to fall apart.  With advanced concepts, all of your worst design biases begin to snowball into that which makes the design unfeasible.   What happens next is very interesting!

I believe you'd still be subject to some ugly pressure waves.

Online KelvinZero

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Re: Asteroid Impact Shelters Using Deep Sea Stations
« Reply #8 on: 08/05/2017 11:44 PM »
What other benefits from the technology would a self sustaining/colonized deep sea station provide?  Does this align with human space flight technologies such as human exploration, power generation, ISRU, advanced transportation vehicle development?
IMO most of the worlds we colonise will be ice balls like Ceres, Europa etc. There are estimates of up to 10,000 such worlds when you include the Oort cloud. We may trivially, even inadvertently, terraform these worlds to mimic the bathepelagic zone on earth simply by our waste heat. There are many potential advantages: a heat dump more convenient than space radiators, industry that involves large bodies of water, robust protection from radiation and explosive decompression, ocean farming, a large biosphere. They could end up ocean worlds under protective eggshells of ice. Rather than building into rock which could continually be subsiding and dropping out beneath you as the liquid zone expands, you could build submarine cities under the ice. These could probably relocate as necessary.

Offline hop

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Re: Asteroid Impact Shelters Using Deep Sea Stations
« Reply #9 on: 08/06/2017 12:40 AM »
It's pure opinion with advanced concepts as to when they are not achievable.
Only if you refuse to do analysis and ignore the analysis already done by others.
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So in other words, I've taken the assumption that the amount of nuclear material to be mined to 'nuke' an asteroid is unachievable.
This is clearly false, humanity collectively has a ~gigatons worth nukes ready to use on short notice and a bunch more in storage or waiting disposal. For the kind of time and money it would take to move millions of people into self sustaining under-sea colonies, we could launch all of them into space, and the cold war proves that we can produce a whole bunch more on relatively short notice if sufficiently motivated
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Where the nuke concept 'snowballs' is you have to store enough material safely, and it could be so large of a facility that it alters the planetary landscape to pull off.
We're already storing the material!
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There are news reports that there isn't enough nuclear material even for another Mars rover.
This is a totally different application of a different material.
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The global economy would have to shift, but may be easier than developing a technology that is unknown to exist and is beyond the horizon technologically (e.g. Gravity tractors).
You should read up on what a gravity tractor is. It's not some far-out speculative technology, it's a straightforward extension of stuff we have already proven. It's not generally considered suitable for km scale asteroids, but that's because it's traded against other realistic options, not relocating a significant fraction of the earths population...

Offline hop

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Re: Asteroid Impact Shelters Using Deep Sea Stations
« Reply #10 on: 08/06/2017 02:41 AM »
How much lead time is needed to divert an asteroid using a gravity tractor?  Just assume it's a Chicxulub II asteroid that is over 10+ km in diameter. 
As I said, gravity tractors are generally not considered suitable for large asteroids like this. Lead times of decades are usually assumed for small objects.

However, they are typically being traded against other options like nukes, not "relocate a billion people to self sustaining undersea habitats in a few years" There is no precedent or model for that, so trying to estimate what you could do with equivalent effort seems pointless.

In reality, no one is spending much time planning seriously for 10km+ impactors, because we have almost certainly discovered all the near earth asteroids in that size range, and the warning time for comets is too short to do anything (certainly including your proposal!). edit: and impacts of things this big are extremely rare.
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It's new concept to me.  At first blush, it doesnt seem likely to work because the best payload to intercept an asteroid in time seems pretty small.  The gravity of an orbiting vehicle is miniscule! 
That's why the people who study these things use math. Yes, the gravity is minuscule, but change in velocity required to turn a hit into a miss is also minuscule if you have decades of warning.

Some of the talks I linked to in the other thread discuss an "enhanced" gravity tractor, where the gravity of the tractor is increased by picking up material from the asteroid.
« Last Edit: 08/06/2017 02:58 AM by hop »

Online KelvinZero

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Re: Asteroid Impact Shelters Using Deep Sea Stations
« Reply #11 on: 08/06/2017 05:43 AM »
Anyways.  For this thread, let's think about surviving a large asteroid impact. 

Now why is it clear that there are no Chicxulub class asteroids threatening Earth??
I think one of the greatest tools for protecting humanity from extinction events (asteroid, plague, nuclear war, nuclear winter, zombies) would be mastering self sufficient habitats separate from earth's biosphere.

You get the first 90% just by building these habitats. You probably get another 90% of the remaining 10% by location. You probably get 90% of the final 1% by moving a self sufficient colony to just one other world.

I don't know about Chicxulub class asteroids but we certainly can't absolutely rule out Chicxulub class comet impacts.

Offline hop

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Re: Asteroid Impact Shelters Using Deep Sea Stations
« Reply #12 on: 08/06/2017 05:49 AM »
Here is confirmation that the NASA redirect mission has gone the way of the dinosaurs.
That particular mission being canceled has nothing to do with the viability of the gravity tractor concept.
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What is a nuclear blast going to do to a 10km+ diameter asteroid if there is no atmosphere to use force the blast wave upon the asteroid??? The only blast will be a few hundred pounds of hot plasma that whispers upon the rocks at high temperature.
Most of the energy is radiation: Neutrons, x-rays and stuff like that. The radiation is absorbed by the asteroid material, which vaporizes and imparts a force on the asteroid as it expands, much like the Orion pulsed nuclear propulsion proposal. If one nuke doesn't provide enough impulse to do the job, repeat.

This has been modeled and found to be effective, though I don't know how much as been done for 10 km sized bodies. The paper I linked earlier (http://forum.nasaspaceflight.com/index.php?topic=43359.msg1706406#msg1706406) has a whole section about using surface bursts for this. With math.

Quote
Now why is it clear that there are no Chicxulub class asteroids threatening Earth??
10 km asteroids are pretty easy to spot, so any in near earth orbits would likely have been detected already.  There are only 8 objects listed in https://ssd.jpl.nasa.gov as NEOs with diameter >= 10km, and half of them are comets. As I mentioned before, there is some risk from comets in the size range, but we this sort of impact is a one in a tens of millions of years event.

Offline meberbs

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Re: Asteroid Impact Shelters Using Deep Sea Stations
« Reply #13 on: 08/06/2017 03:26 PM »
I still have a biased view that Tunguska may have been a relatively small comet. This bias may be just from the eyewitness accounts heard multiple knocking sounds.  The eyewitnesses of the Tunguska explosion likely did not use math.  The fact that it was daylight (7:17am) implies without math that it could have been a comet that had an inbound trajectory after traversing the sun.  Chelyabinsk was at 920am.  Again a sunward side entry.
Time of day has only minimal relation to direction an impactor was travelling before entering Earth's gravitational influence. Given that the Earth is also orbiting the sun, an inbound or outbound commet trajectory both could hit at a local time of "morning"

Are these asteroid surveys currently able to see comets or asteroids that are on the far side of the sun?  I've got this impression that surveys now are only searching the night sky using ground based telescope arrays of the night side.
Some studies (past and future) use space based telescopes that wouldn't have a day/night restriction.
The "On the far side of the sun" portion of your question doesn't even mean anything. There are no objects in the solar system that are described by that for long. It becomes utterly irrelevant when a survey lasts for years. For planetary defense, the asteroids that matter all have orbits that can intersect Earth's by definition these spend time outside Earth's orbit.

Also the ability to see Venus and Mercury in the night sky illustrates that "night sky only" still has a large field of view to cover objects currently closer to the sun than Earth.

I say it is more plausible to have something unknown come out of left field as a comet than a rogue asteroid.
Yes, but not for the reason you seem to think. It is because there are comets out there that spend centuries so far from the Earth and from the sun that they would be too dim to seem them from Earth. By the time they would be visible, we wouldn't have time to do much of anything including build undersea shelters.

I cannot give myself a favorable probability of diverting an asteroid! 
Why not? There are multiple viable methods that could be implemented with no new technology development.

I'd give an asteroid redirect mission much less than 1% chance.
Again, you have seemed to ignore all facts when coming up with this. The fact is that such a mission would have an excellent chance of success.

So this is how advanced concepts begin to get seedling funds for further research.  So it seems plausible to me that someone in China is funding this.
They quite explicitly have different reasons for funding it which you stated in your opening post, and what they are doing is many orders of magnitude smaller than your suggestion.
« Last Edit: 08/06/2017 03:28 PM by meberbs »

Offline hop

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Re: Asteroid Impact Shelters Using Deep Sea Stations
« Reply #14 on: 08/06/2017 07:29 PM »
Here is a tough question... Is there a database of 1-10km+ diameter asteroids that may be on a trajectory to impact Mars or the Moon?

We don't currently know of any significant, near term (i.e. decades) impacts. AFAIK, Shoemaker Levy 9, 2008 TC3 and 2014 AA are the only impacts of natural objects detected in advance.

There are some NEOs with small but non-zero Earth impact risks on timescales of several decades. See http://www.minorplanetcenter.net/iau/lists/PHACloseApp.html for example.

I'm not aware of anything like this for the Moon or Mars, but potential impacts of km scale objects are something the community notices and gets very excited about. See SL9 and C/2013 A1 for example.
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Doing the math of a comet trajectory around the Sun is highly uncertain as the composition of any object is unknown.
Comets are subject to non-gravitational forces, but those forces are pretty small. The other problem with comets is that the nucleus is usually hard to resolve, which makes determining the exact position (and hence, the orbit) more difficult. However, these are both relatively small effects. It might make it difficult to certain whether an encounter will impact or miss by a few thousand km, but it's not going to cause the object to suddenly be millions of km away from the expected trajectory.

Offline tea monster

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Re: Asteroid Impact Shelters Using Deep Sea Stations
« Reply #15 on: 08/06/2017 08:44 PM »
1. You don't have to just get X Million people to another planet - you have to set up a completely self-sustaining colony that will be the sole continuation of the human race. No more shipments from Earth - it's toast, remember? That complicates your colony efforts substantially.

2. You don't have to 'Nuke' an asteroid - i.e. 'blow it to smithereens'. You just have to hit it a few times when it's far enough out to change course - imagine a sort of sideways Orion pulse-rocket. Just a few degrees to miss Earth is all you need.

3. I'm pretty sure it would be easier and more survivable to create underground shelters. The ones in the neighborhood of the impact will be turned into tinned tomato puree, but if they are built correctly (shock absorbers, etc) ones around the planet from the blast should survive the impact. The main problem then will be keeping the inhabitants alive for however long it takes for the sun to come back out and life to be sustainable again on the surface. It would be the same deal as an off-Earth colony, but without any solar energy. You'd have to use hydroponics and a nuclear reactor to keep the lights on the food growing for anything up to 100 years or so. This will be much cheaper than moving a large portion of the populace off the planet and should allow you to save more people.

4. Yes, that's a shot of one of the Conshelf habitats that was used. Source: http://www.messynessychic.com/2013/05/27/remains-of-an-underwater-habitat-left-by-1960s-sea-dwellers/

Offline Propylox

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Re: Asteroid Impact Shelters Using Deep Sea Stations
« Reply #16 on: 08/06/2017 09:04 PM »
This isn't my kinda thread, which I'll address in post-script, but I can provide some guideposts and corrections.
(snip) But I'm trying to bound the problem first. Thus far, it seems the concept of operations is:
• Transport a large population to deep sea stations.
• Sustain the population and local resources to until it is time to return to the surface. ...
A large percentage of the World's population don't live in houses, much less cities, so it's fairly ridiculous to think we'd build all that housing "just in case". Similarly, a large percentage don't have enough to eat so don't count on building that level of food production "just in case".
I would significantly downsize the habitable ambitions. These could be spread across the globe and find commercial use as farms until used as shelters. But I wouldn't plan on more than 0.1 to 1.0% of the population due to construction costs and emergency transport restrictions - not simple in number of ships, but fuel and port bottlenecks, and supplies these ships would also be loaded with.

1) If there was a pressure wave, is it reasonable to reflect these waves using a barrier?  Imagine a castle wall with the occupied deep sea station portion behind it.
2) What if a deep sea station was built in a deep lake surrounded by land structures?  This way if a global tsunami were to be initiated, the lake would be protected by: 1) depth and 2) breadth of land
Re1) Doesn't work that way. A pressure wave is analogous to a change in depth, not a front. Imagine your underwater station had a depth of 35m, then rose to 25m as the wave approached, then immediately dropped to 70m at impact, rose to 50m and stayed their a bit before returning to 35m. The station isn't really moving, but that's what pressure does and a wall won't change that.
Re2) Good idea. The Great Lakes, Caspian and Black Seas, even walling off the Sea of Cortez would isolate those water bodies from tsunamis. Though a tsunami could still reach and "overfill" the sea if tall enough.
------------------------------------------------------------------------------------------
  One consideration for your design is depth. I'd recommend around 45-65m as it needn't be deeper and could still be evacuated directly with one breath.
Any large impact event will be followed by smaller meteorites, as well as eject material to make more meteorites. This depth should be sufficient to stop the velocity and pressure waves from small impacts overhead, though they'd still sink onto you. Any atmospheric changes, storm waves and developing icesheets (including a drop in sea levels) shouldn't effect a base at this depth.
  Another consideration is anchoring. Depending on surface topography a tsunami can produce very strong currents. You should also expect regular earthquakes after such an event (why underground is a bad idea). A bouyant base would be chained to the seafloor while a weighted base would be built on earthquake pillars - but both would need dampeners.

How much lead time is needed to divert an asteroid using a gravity tractor? ... At first blush, it doesnt seem likely to work because the best payload to intercept an asteroid in time seems pretty small.  The gravity of an orbiting vehicle is miniscule!
Correct, gravity tractors are idiotic and proposed by people that can't add. More force can be delivered by impacting than floating nearby, especially if intercepted head-on instead of trying to catch up to like a gravity tractor. I'm sure hop has studies about their greatness.

Now why is it clear that there are no Chicxulub class asteroids threatening Earth??
We don't currently know of any significant, near term (i.e. decades) impacts. AFAIK, Shoemaker Levy 9, 2008 TC3 and 2014 AA are the only impacts of natural objects detected in advance.
There are plenty of km-scale and tens-of-km-scale threats. By hop's own admission, there's no knowledge of any and scant chances of detecting any in advance. Beyond the asteroid belt is a sea of Centaurs, Trojans and moons (notably Margaret of Uranus) in unstable or precarious orbits - any of which would only need a slight nudge to leave their orbits and possibly impact Earth. This is very unlikely as the age of the solar system has already removed such occurrences, but the threat does still exist and the only way to detect it would be with much larger space telescopes.
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PS- I usually stay away from the outlandish, absurd or physically impossible like Mars terraforming, railgun or space elevator launch, housing a billion mermen or morlocks, etc. unless there's open minds -or- outright liars. Your proposal fell into the former while hop's asteroid redirect assertions fell into the later. I hoped this helped as it will be my only comment on the subject.

Offline meberbs

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Re: Asteroid Impact Shelters Using Deep Sea Stations
« Reply #17 on: 08/07/2017 12:32 AM »
How much lead time is needed to divert an asteroid using a gravity tractor? ... At first blush, it doesnt seem likely to work because the best payload to intercept an asteroid in time seems pretty small.  The gravity of an orbiting vehicle is miniscule!
Correct, gravity tractors are idiotic and proposed by people that can't add. More force can be delivered by impacting than floating nearby, especially if intercepted head-on instead of trying to catch up to like a gravity tractor. I'm sure hop has studies about their greatness.
You might want to go learn some orbital mechanics before you start accusing people of not being able to add. The asteroid is the one that would have been doing the "catching up" for ARM.


Anyway if you actually read this thread, you would see multiple statements that depending on the situation, a gravity tractor is not always the best choice.

PS- I usually stay away from the outlandish, absurd or physically impossible like Mars terraforming, railgun or space elevator launch, housing a billion mermen or morlocks, etc. unless there's open minds -or- outright liars. Your proposal fell into the former while hop's asteroid redirect assertions fell into the later. I hoped this helped as it will be my only comment on the subject.
Actually your assertions that simultaneously accused scientists of not being able to add while demonstrating your own lack of knowledge regarding orbital mechanics would be what deserving of the second category if anything in the thread is.
« Last Edit: 08/07/2017 12:40 AM by meberbs »

Offline meberbs

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Re: Asteroid Impact Shelters Using Deep Sea Stations
« Reply #18 on: 08/07/2017 12:48 AM »
Ok.  Very good.

What would you describe as the functional requirements for an asteroid redirect of a Chicxulub II class asteroid?  What probabilities would you attribute to each functional requirement (be favorable/ or estimate to be no greater than X%)? Then what is the off the cuff chance of success for the mission?

I'll start the first two functional requirements for you...
• Identify the incoming object to impact Earth (assume it is an asteroid or comet).
• Determine the trajectory to assess the time of impact, damage estimates within a 1 minute tolerance.
....
Lets agree to ignore those, because they would have to happen for your plan as well, (ignoring the arbitrary "1 minute tolerance" that I am not even sure what you mean by.)

The real probability for the mission would be things like
-launch (>95% success)
-mission operations (similar to typical interplanetary probe. Built in redundancy generally leads to >90% chance of success, details would depend on mission type (gravity tractor, nuclear deflection, etc.))
-If it is important enough and assess the risk of failure high enough, we build an entire second spacecraft for backup.

Offline Nomadd

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Re: Asteroid Impact Shelters Using Deep Sea Stations
« Reply #19 on: 08/07/2017 12:51 AM »

Most of the energy is radiation: Neutrons, x-rays and stuff like that. The radiation is absorbed by the asteroid material, which vaporizes and imparts a force on the asteroid as it expands, much like the Orion pulsed nuclear propulsion proposal. If one nuke doesn't provide enough impulse to do the job, repeat.

This has been modeled and found to be effective, though I don't know how much as been done for 10 km sized bodies. The paper I linked earlier (http://forum.nasaspaceflight.com/index.php?topic=43359.msg1706406#msg1706406) has a whole section about using surface bursts for this. With math. Most people don't realize that they can already build nuke and conventional warheads that can take many thousands of Gs and still operate.

I see a lot of analysis of nukes going off near the surface of asteroids. Why in the solar system would they do that? They already have nuclear bunker busters with 400-900kt warheads that can go through 150 feet of concrete before detonating. Atmosphere is irrelevant. If you're serious, design some asteroid busters with 9mt warheads and have enough for followups if the first one leaves some large pieces headed in the wrong direction.
« Last Edit: 08/07/2017 12:53 AM by Nomadd »

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