Asteroid defense office

[Rune]

On 10/1/2016 at 10:45 PM, WedgeAntilles said:

Actually, even before we do this, there's something else we should do first, and we already have the technology to do it.

What we should do is stick a few nuclear bombs on a remote-controlled spacecraft--some of the warheads being mounted on missiles, the others on robotic landing pods--then fly the ship out to an asteroid and test-fire the warheads against it to observe the effects. How much damage is done, how much does the asteroid's trajectory change, that sort of stuff. The first step in our plan needs to be to find out what kind of weapons/tactics/tricks/gizmos will actually work to divert or destroy an incoming threat, and the nature of the countermeasure that actually works will probably have considerable impact on the nature of the orbital platform that deploys it.

There will be a minor problem with that treaty somewhere that forbids nuclear bombs in space, to which I say tough knickers.

Actually, before we even do this, there's something else we should do first, and we already have the technology to do it....

Find and classify all the crap that there is on the solar system, and see just how many of them we have to worry about.

We have a truly insignificant number of asteroids tracked right now. Sure, most of the big ones in the belt, but go below 10kms in diameter, of >5AU in average distance from the sun, and you will see that we have pretty much no freaking idea of what's out there, or if anything is coming our way. A 30km comet comet could be coming straight at us from the Oort in this very moment, and we would know nothing about, nor have had any chance to find out about it, before it says hi and blows up a continent.

I know blowing crap up is a compelling idea, speaking to out inner child, but asteroid defense is something that is mainly about telescopes. LOTS of telescopes. For starters, a few dozen infrared Hubbles could start to make a dent in the asteroid/comet population beyond Jupiter, and finally allow us to find all the small ones in the inner system, that could very well take a city out. It is not only a matter of finding them once, you have to keep refining their numbers just in case some close encounter with something changes their trajectories, so it would be a never-ending task. And currently no one is giving nearly enough money for it.

So before we talk about nukes and asteroid impactors, about testing surface compositions and developing diverting technologies... please, let us increase the budget for asteroid-hunting efforts. By a few orders of magnitude at least.

 

Rune. And think of the science done as a consequence!

Edited January 19, 2016 by Rune

[Rune]

On 19/01/2016 at 8:10 AM, WedgeAntilles said:

Then, the heat shielding on a space shuttle is for what, precisely.....? There, that takes care of that.

Wow. Just wow. You don't even know how wrong you are there. The heating during reentry is caused by compression, in its vast majority. The relevant term is "compression heating", google it up for further clarification, since it is one of the most common misconceptions regarding spaceflight. Googling something like "why do spacecraft heat up when they reenter" should also offer the relevant explanation (and that should show you the level of blunder you committed here). Then when you have compressed superheated plasma in the bow shock, that's when the radiated energy of said plasma starts ablating your spacecraft away. The ablated stuff, BTW, slows down and remains in the atmosphere as a dust particle... and the smaller it is, the more time it will remain up.

Edited January 25, 2016 by KasperVld
There's no need for that.

[Nikolai]

6 hours ago, WedgeAntilles said:

Then, the heat shielding on a space shuttle is for what, precisely.....?

To take care of the heat that comes from massive compression as the Shuttle moves quickly through the air.  Not heat from friction.

6 hours ago, WedgeAntilles said:

And none of this happened with the recent Russian impact.

The Russian impact was caused by something orders of magnitude smaller than what we are talking about.  (The Chelyabinsk meteor was about 20 meters across, and the dino-killer about 10,000 meters across -- some 125 million times greater volume.  I also encourage you to read up on the dust that was left by the meteor, and consider what a commensurately larger amount of dust would mean: Popova, Olga P.; Jenniskens, Peter; Emel'yanenko, Vacheslav; et al. (2013). "Chelyabinsk Airburst, Damage Assessment, Meteorite Recovery, and Characterization". Science 342 (6162): 1069–1073.  The damage from this particular meteor was also significantly mitigated by its low angle of attack.)

6 hours ago, WedgeAntilles said:

It was an ad hominem that fredinno committed when he referred to me as "some random guy on the Internet instead of somebody who studies this stuff for a living". Which is kind of ironic because he has no idea who I am, and no idea what I actually do for a living.....

No, but you have yet to demonstrate that you know what you're talking about.  There's no reason for any third party to guess that you're anyone but "some random guy".

6 hours ago, WedgeAntilles said:

Well, letsee......first thing that comes to mind: scientists predicted disaster due to global warming. Then global cooling. Then global warming. Then global cooling. Then global warming. No joke here, that's what actually happened over the course of the last century or two. Every time the temperature trend changed its mind and headed in the other direction, Science changed its Doomsday prediction accordingly.

I think there's a large difference between the paper or two suggesting the possibility of cooling (accompanied by a handful of magazine articles and a book published for a lay audience) and the large consistency of evidence we currently see among many different lines of independent inquiry for global warming.  Do you think that means anything?

7 hours ago, WedgeAntilles said:

when the concept of massed groups of bombers was invented somewhere between WWI and WW2, "modern" science predicted it would single-handedly win wars and render entire nations lifeless--which of course didn't happen

That's more a political point than a scientific point, unless you can show me some data.

7 hours ago, WedgeAntilles said:

predictions about the Large Hadron Collider accidentally destroying the Earth (yes, some of the people making those ridiculous predictions were scientists!)

Even those that I've read that did pointed out that the probability was so small as to be completely negligible.

7 hours ago, WedgeAntilles said:

the Y2K bug

I saw lots of fearmongering, but not a whole lot of anything from the science community.  The engineers and technicians were busy solving the problem.

7 hours ago, WedgeAntilles said:

when I was a kid reading up on Albert Einstein, I came across his use of a "cosmological constant" in his equations to make the universe static instead of expanding, and right away I realized he'd committed a science foul

So did he.  http://www.scholarpedia.org/article/Cosmological_constant

7 hours ago, WedgeAntilles said:

Bottom line: scientists are people. They make mistakes.

No one's contesting that.

7 hours ago, WedgeAntilles said:

What does that have to do with this thread? Simple: it forms a trend.

I'm not sure that "trend" is as significant as you're making it out to be.  It requires, for example, amplifying the voices of a few and making it equivalent to the scientific consensus.

7 hours ago, WedgeAntilles said:

Just for a kick I looked up the Tsar Bomba in a few places, and didn't find any mention of significant effects from atmospheric heating.

Tsar Bomba was fifty megatons -- orders of magnitude smaller than what we're talking about here.  All the nuclear explosions detonated in the twentieth century only add up to 600 MT, which doesn't even approach a thousandth of a percentage point of the energy released by the dino-killer.  I'd like to see some indication that five million Tsar Bombas, all dumping their energy directly into the atmosphere, would do nothing significant.  (And that's important here -- in discussing our scenario where all of the energy is dumped into the atmosphere.  Nuclear testing is thought to have caused more cooling than heating, based on the amount of ground kicked up: http://science.sciencemag.org/content/222/4630/1283.short)

7 hours ago, WedgeAntilles said:

Random side note: shattering an asteroid in space will produce an expanding debris cloud. Meaning some of the fragments (actually most of them) will, instead of hitting Earth straight-on, hit the atmosphere at an angle. Some of the fragments will therefore skip off the atmosphere and back into space. If the asteroid isn't going to hit Earth dead-center (and a dead-center hit is very unlikely), the shattering projectile should be fired from the "more center" direction to knock the asteroid more off center. Moral of the story? Hit the asteroid with the shattering weapon when it's as far away as possible, to disperse the debris cloud as widely as possible--or maybe even cause the whole thing to bounce off the upper atmosphere and back into space without hitting Earth at all!

If you're fortunate enough to be able to hit it early enough, sure.

[Nikolai]

Something to mention in passing: 240,000,000 megatons (the dino-killer's kinetic energy) is approximately 10²⁴ joules.

The specific heat of the air at room temperature is about 1158 joules/(kg * degree C): http://physics.info/heat-sensible/  The mass of the atmosphere is about 5.14x10¹⁸ kg: http://journals.ametsoc.org/doi/abs/10.1175/JCLI-3299.1.  This gives us a heat capacity of 5.95x10²¹ joules/(degree C).  Thus, as a BOTE approximation, we see that causing the dino-killer to pulverize completely in the atmosphere would raise its (the atmosphere's) temperature about 170 degrees C.

Note that kinetic energy scales linearly with mass, and temperature rise scales linearly with energy input, so even getting four-fifths of the asteroid mass to miss us would cause the temperature to rise 34 degrees C.  It's possible to get this (and better) to miss us with an expanding debris cloud if you can be assured of reducing everything to a small enough size to be incinerated in the atmosphere if you catch it early enough, but you need to be sure.

Edited January 19, 2016 by Nikolai
Tried to improve readability a bit

[magnemoe]

On 14.1.2016 at 3:57 PM, Nikolai said:

That's not quite true.  You might end up with less surface deformation, but if all your chunks intercept the Earth's atmosphere, then all the energy is still delivered to Earth -- even if it just gets dumped in the atmosphere.  So if your problem is (say) a dinosaur-killer that could release enough heat on impact to really screw with the climate for years and cause mass extinctions, you haven't made the problem go away by shattering the target.  And if enough dust remains in the atmosphere from all the little pieces, you have "nuclear winter".

All that assumes, of course, that all of your chunks are small enough to burn up in the atmosphere and not, say, detonate when hitting the denser layers and cause damage that way.  Keep in mind that the Chelyabinsk meteor is thought to have been only 15 meters across or so.  For those that do get low enough, the damage radius is proportional to the cube root of the impact energy, and now you have a lot more radii scattered about.  (Less of the energy is spent carving out depth in one crater in one spot, and more of it is spent obliterating the surface all over.)  There's a reason MIRVs and cluster bombs are fearsome weapons.

You could do this well if you had some control over the size of the resultant pieces when you shatter the big one, but the reality is that you don't, and you don't want to experiment under these circumstances.  The eggheads are right.

Mirv or cluster does more damage than an single bomb of the same mass as damage area don't grow linear with bomb size its cube root as you say
However shattering is no catastrophe as many say, first the parts who don't stay close together will miss earth so if you shatter it well and at the same time put an force on the entire asteroide, think surface detonation on an gravel pile just fragments will hit earth. 
Worst case would be fragmenting but not enough velocity change to miss. 

[magnemoe]

On 13.1.2016 at 7:38 PM, Red Fang said:

I'd like to see international effort to test some nuclear golf concepts on asteroids. It may prove to be a viable option, for some, or most intercepts. Depending on number of shots, development prices may skyrocket like a Sprinting Gazelle, especially if it turns out development of new warheads is needed. 

Nuking an asteroid to give it several cm/s or m/s to change its orbit enough to miss Earth would answer several questions. 
- Is it feasible at to use nukes to disturb asteroid orbits?
- How do different asteroids react to different nukes? (solid iron, solid rock, rubble piles, comets... vs. regular/neutron/shaped charges)
- What are optimal parameters (ie, standoff distance, yield, warhead type) for redirecting different asteroids?
- What are ultimate limitations of nuke-the-asteroid method in regards of object size, composition, mass, orbit, warning time etc...
 

And an additional, programmatic questions:
 - How to integrate warhead, kill vehicle and launch vehicle in a way that is low-cost, storable long term, and quick to launch (hours/days).
- How many different rocket types would you need to have on-hand?  (Would a heavy ICBM derived vehicle do for most cases?  ...like Dnepr-1. Would you need capability to quickly integrate, fuel and launch a pulse unit on a heavy/medium launcher such as DeltaIV heavy, Proton, Ariane 5 / Soyuz, Falcon 9 ?)
- How would you store pulse units to make them safe from theft and unauthorized access?

 Now that I have listed all those things, I think this would not be cheap.  Lets say 5-10 test-shots, with several test-launches... developing 1-3 standard delivery vehicles in different weight classes. Potential development of new warheads. In the end, buying a stand-by force of some 20 ( ? ) launchers and delivery vehicles, new storage facilities, refurbishing some dozen ICBM silos, paying for storing those things for decades... Yeah, this goes well into tens of $ billions easily. At best, I can imagine someone, somewhere having a paper project on how to crash-launch a nuke to intercept an asteroid...

I guess something like the concept of orion pulse rocket drive charges would be perfect. Don't know how hard it would be to modify an existing nuclear bomb for this.
Benefit is that you will hit one side of an asteroid reducing stresses, its an shaped charge so an significant fraction of the energy goes into the tungsten shield who hit the side.

We have decent experience with deep space probes including doing comet and asteroid flybys. Make some of this with integration with warhead, but store warheads together with other nuclear bombs.
You would also need transfer stages or interface for common rockets so you can grab the first ready to fly. 
 

[magnemoe]

On 12.1.2016 at 9:26 PM, SomeGuy123 said:

Global warming is very very slow.  The talk of it being a catastrophe if temperatures rise 3 degrees celsius?  That's predicted to happen at the end of the century, when everyone making decisions now is expecting to be long dead.  

An asteroid is immediate and you can see it coming once you know about it.  I suppose that's one way it could go badly - the actual exact prediction of if the asteroid will impact or not will be uncertain for years because you don't quite know how the asteroid will be affected by sun heating it on it's approach.

More different is who would be interested. The asteroid defense office is an way for NASA to get more money for looking after asteroids because its an danger. 
Its an easy step who don't cost much money, NASA might also want it international as it make it harder for congress to cut as its an international agreement. 
Now say they detect an asteroide who will hit us in 15 years. its not an dinosaur killer but say 500 meter, you can ignore it and hope it hit somewhere uninhabited.
NASA other space agencies will want to hit it to show they are important, military want to test some new nukes and they have not tested for an long time. 
We are talking about a few rocket launches her not something ruining expensive so they launch some probes with nukes 5 years later who intercept and redirect it

Global warming on the other hand is much harder to deal with, far more expensive than say 5 delta heavy launches. 
Add that the interests are far less focused, politicians was fast out with new taxes who has no measurable effect on climate but give money for their other pet projects. 
Then it comes to expensive projects who has an impact they talk very fast about other things. 
Most environmental groups are against more use of nuclear power even if its one of the fastest way to reduce co2 emissions. 
Lots of other issues like disagreement among countries  

 

[The Moose In Your House]

Please no talking about politics/Beliefs such as "Global Warming", I'm not telling you that I think it is real or fake but different people have different beliefs about this subject. And the rules on the forum states: "Political, ideological or religious posts unrelated to Spaceflight, or of a nature deemed likely to result in behavior banned under rule 2.2D".

 

(Forum rules here http://forum.kerbalspaceprogram.com/index.php?/guidelines/)

Edited April 27, 2017 by The Moose In Your House

[Vanamonde]

This thread has been dormant for over a year. How about we let it go back to sleep?