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#176 2016-05-27 14:28:41

GW Johnson
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From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 4,078
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Re: The SLS: too expensive for exploration?

What you describe about asteroids as weapons is exactly why there are so many folks opposed to the asteroid redirect mission.  Once one country does it,  so eventually will others,  and some of them cannot be trusted.  Some don't even trust the US government to do this right.  If the rock is anywhere in cis-lunar space,  it can be misused as a weapon.  Or be the cause of a terrible accident.  Neither is an acceptable event. 

Asteroid deflection is a worthy project far too long neglected.  We need the B612 Sentinel in operation to find the Chelyabinsk-sized threats more reliably,  but NASA has long had an awful "not invented here" attitude problem about that.  If NASA's management had its collective ass kicked up between its armpits,  that bad attitude could be fixed. 

Even so,  once we find these things,  then what do we do about them?  That's a very good question debated at every international biannual asteroid defense conference for the last several years.  I went to the one in Granada in 2009 with a paper to present on an upgrade to the gravity tractor.  There's gravity tractors for long lead time,  and impactors and nukes for little lead time/last ditch defense.  That's about it,  and you don't use nukes the way it has been depicted in the movies.  That crap doesn't work. 

For the impactors and nukes,  results depend critically upon a much better understanding of asteroid physical/mechanical characteristics than we have now.  People call them "rocks",  but most are more like sand and gravel piles,  some with some ice content,  others not.  To correct this knowledge deficiency requires probes/landers,  and ultimately human visits and deflection experiments in-situ. 

Orion/SLS will never be able to do this human visit function;  most of those things are 1 to 4 year missions.  Orion has life support for at most 3 weeks,  which will be about all the time its crew can stand cramped inside the silly thing.  Orion/SLS is a reprise of Apollo,  except they have no lander,  and not enough service module to reprise Apollo 8. 

We cannot yet send men there successfully.  Although,  anything that could take men to Mars orbit successfully could serve to do the asteroid visit job. 

GW

Last edited by GW Johnson (2016-05-27 14:30:05)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#177 2016-05-27 21:27:09

Tom Kalbfus
Banned
Registered: 2006-08-16
Posts: 4,401

Re: The SLS: too expensive for exploration?

GW Johnson wrote:

What you describe about asteroids as weapons is exactly why there are so many folks opposed to the asteroid redirect mission.  Once one country does it,  so eventually will others,  and some of them cannot be trusted.  Some don't even trust the US government to do this right.  If the rock is anywhere in cis-lunar space,  it can be misused as a weapon.  Or be the cause of a terrible accident.  Neither is an acceptable event.

 
That is why we have to make sure only responsible nations get to use it. Fortunately the Responsible nations are in much better shape to redirect asteroids than irresponsible ones. I don't foresee Iran or North Korea ever doing it in the near future, their economies are such basket cases that they'll never have the resources.

Asteroid deflection is a worthy project far too long neglected.  We need the B612 Sentinel in operation to find the Chelyabinsk-sized threats more reliably,  but NASA has long had an awful "not invented here" attitude problem about that.  If NASA's management had its collective ass kicked up between its armpits,  that bad attitude could be fixed.

 
You mean like a space age "Pearl Harbor", I hope not!

Even so,  once we find these things,  then what do we do about them?  That's a very good question debated at every international biannual asteroid defense conference for the last several years.  I went to the one in Granada in 2009 with a paper to present on an upgrade to the gravity tractor.  There's gravity tractors for long lead time,  and impactors and nukes for little lead time/last ditch defense.  That's about it,  and you don't use nukes the way it has been depicted in the movies.  That crap doesn't work.

 
The Answer is, you relocate those asteroids so you can effectively mine their resources and thereby pay the "deflection bill." I'd say, whoever significantly changes the orbit of an asteroid owns that asteroid, this will conveniently exclude major bodies such as Mars, Venus, or Mercury, so no one is going to claim those as their personal planets! Of the asteroids, only the small ones, a few miles or less in diameter, do we have a realistic chance to relocate, and fortunately it is the smaller ones that we can deflect that are the most threatening. They are more numerous after all, We know the orbit of Ceres and Vesta after all, and they don't pose a threat, if they did, there would be nothing we could do about them anyway.

For the impactors and nukes,  results depend critically upon a much better understanding of asteroid physical/mechanical characteristics than we have now.  People call them "rocks",  but most are more like sand and gravel piles,  some with some ice content,  others not.  To correct this knowledge deficiency requires probes/landers,  and ultimately human visits and deflection experiments in-situ.

 
I think what you need to do is subject these asteroids to only gradual accelerations, not sharp ones or use gravity to do the accelerating for you. We basically have to deplete all the Earth crossing and near earth asteroids and exploit and use up those first! We can do whatever with them, build O'Neill habitats, or Solar Power satellites, or other things, but get rid of those threatening asteroids so they don't collide with Earth. Then on the longer term, we have to worry about those comets!

Orion/SLS will never be able to do this human visit function;  most of those things are 1 to 4 year missions.  Orion has life support for at most 3 weeks,  which will be about all the time its crew can stand cramped inside the silly thing.  Orion/SLS is a reprise of Apollo,  except they have no lander,  and not enough service module to reprise Apollo 8.

 
A lander can be quickly cobbled together should the need or desire to explore the Moon arise, we still got the plans for the LEM, but we can do better of course. A Mars interplanetary spaceship could also be used as an asteroid prospector with some modifications. I'm afraid their might have to be a Military-private partnership between mining companies and the Defense Department, because of the weapon potential of these asteroids.

We cannot yet send men there successfully.  Although,  anything that could take men to Mars orbit successfully could serve to do the asteroid visit job. 

GW

Last edited by Tom Kalbfus (2016-05-27 21:28:35)

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#178 2016-05-28 05:12:35

Terraformer
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Re: The SLS: too expensive for exploration?

It just so happens that the countries which have been declared responsible enough to do it by the most powerful countries in world are the most powerful countries in the world. Who would have thought it?

If any country is given the keys to redirect asteroids, I suggest it should be a tiny one that doesn't spend it's time trying to build empires. That rules out the 5 permanent members of the UN security council.

Are rubble pile asteroids actually much of a threat? Surely they would break up and turn into a very big meteor shower? I would expect the solid ones to be the ones to worry about.


"I guarantee you that at some point, everything's going to go south on you, and you're going to say, 'This is it, this is how I end.' Now you can either accept that, or you can get to work." - Mark Watney

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#179 2016-05-28 07:48:08

Tom Kalbfus
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Re: The SLS: too expensive for exploration?

Terraformer wrote:

It just so happens that the countries which have been declared responsible enough to do it by the most powerful countries in world are the most powerful countries in the world. Who would have thought it?

Evil is self-destructive in the long run, it is not surprising that most evil run countries do not have the resources to do this, they are too busy starting wars, and making themselves poor, stealing things other people have got, to build up the resources to have the technological base to do this. Look at what happened to the Soviet Union! There biggest weakness was themselves, they managed to launch a few satellites and send a few men in space using technology and resources they largely stole from the Third Reich, which the Third Reich originally stole from someone else. These empires don't really know how to produce, they can only steal, they destroy much which is around them and they take what's left for themselves, they don't know how to produce it! Fortunately this gives the World's free democracies an advantage over them, because the World's totalitarian dictatorships have a habit of tripping over their own feet, they only beat us if we let them! As we had the Soviet Union in the 1950s with regard to Sputnik.

If any country is given the keys to redirect asteroids, I suggest it should be a tiny one that doesn't spend it's time trying to build empires. That rules out the 5 permanent members of the UN security council.

The 5 permanent members of the UN security council are China, France, Russia, the United Kingdom, and the United States.
I don't know why China was on that list and not the Philippines, both were occupied by Japan during World War II, and China descended into Civil War caused by the Maoists/Communists, after they were weakened by Japanese occupation. China is not an advanced economy, it just has a lot of people, they export a lot of cheap things that require a large labor content. Russia has done little besides build space stations in low Earth orbit, and send space probes to Venus. France, the United Kingdom, and the United States have advanced economies, they could do some asteroid mining, but then so too could Germany or Japan. In my mind, the most dangerous countries also happen to be poor and are run by dictators, that would include China and Russia.

Are rubble pile asteroids actually much of a threat? Surely they would break up and turn into a very big meteor shower? I would expect the solid ones to be the ones to worry about.

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#180 2016-05-28 10:24:34

GW Johnson
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From: McGregor, Texas USA
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Posts: 4,078
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Re: The SLS: too expensive for exploration?

"Are rubble pile asteroids actually much of a threat?" -- that's exactly what the Chelyabinsk object actually was.  Very few of the under 10 km-size objects are "solid bodies" mechanically.  Almost none,  in point of fact. 

They don't just burn during entry,  they suddenly break up when the drag forces exceed the cohesive forces.  But at astronomical speeds,  that breakup resembles a nuclear explosion. 

As for "responsible countries",  what is missing from Tom's diatribe is any sense of ethics beyond exceedingly-selfish self-interest.  I pity people who lack it.  Their internal lives lack so much.

Tom is correct that the powerful nations today are the ones most likely to take on the asteroid defense task.  The motivation for that must be as stewards for all of mankind,  or else it will get twisted eventually to evil,  as so many things have throughout history. 

I sort-of trust my own country to do it for that reason,  China and Russia-as-it-is-under-Putin,  not so much at all.  Bear in mind,  that if we have too much bad leadership here in the US,  we could easily fail to measure up as well.  Our congress is demonstrably rather poor in recent years. 

With China,  the culture evolved over millennia is hierarchical bullying,  completely lacking the fair play ethics that has recently evolved in some but not all the west.  They will continue to behave as bullies for the forseeable future,  because evolution of fair play ethics demonstrably takes centuries.  Russia sort-of evolved the same way as China,  and it was exacerbated under Soviet communism,  and now again by Putin-the-dictator.  His personal mode of operation is hierarchical bullying. 

GW

Last edited by GW Johnson (2016-05-28 10:37:43)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#181 2016-05-28 20:24:46

Tom Kalbfus
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Re: The SLS: too expensive for exploration?

GW Johnson wrote:

"Are rubble pile asteroids actually much of a threat?" -- that's exactly what the Chelyabinsk object actually was.  Very few of the under 10 km-size objects are "solid bodies" mechanically.  Almost none,  in point of fact. 

They don't just burn during entry,  they suddenly break up when the drag forces exceed the cohesive forces.  But at astronomical speeds,  that breakup resembles a nuclear explosion. 

As for "responsible countries",  what is missing from Tom's diatribe is any sense of ethics beyond exceedingly-selfish self-interest.  I pity people who lack it.  Their internal lives lack so much.

When you build a bridge, you build it to stand up to the maximum traffic load conceivable and then double it, you assume the material in it will have flaws, so you use thick beams and way more material than you actually need to make sure the bridge stands up under all conditions. When you want to design a program to remove asteroids from threatening orbits, you have to assume self-interested humans, as that is usually more likely the case, then the noble selfless types, and one way to appeal to self-interest is to encourage asteroid mining and profits from that. We can harness capitalism to remove near earth asteroids, let people make profits off of that and save lives as well. I find nothing wrong with that.

Tom is correct that the powerful nations today are the ones most likely to take on the asteroid defense task.  The motivation for that must be as stewards for all of mankind,  or else it will get twisted eventually to evil,  as so many things have throughout history. 

I sort-of trust my own country to do it for that reason,  China and Russia-as-it-is-under-Putin,  not so much at all.  Bear in mind,  that if we have too much bad leadership here in the US,  we could easily fail to measure up as well.  Our congress is demonstrably rather poor in recent years. 

With China,  the culture evolved over millennia is hierarchical bullying,  completely lacking the fair play ethics that has recently evolved in some but not all the west.  They will continue to behave as bullies for the forseeable future,  because evolution of fair play ethics demonstrably takes centuries.  Russia sort-of evolved the same way as China,  and it was exacerbated under Soviet communism,  and now again by Putin-the-dictator.  His personal mode of operation is hierarchical bullying. 

GW

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#182 2016-05-29 07:26:07

Terraformer
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Re: The SLS: too expensive for exploration?

If the bodies could be blown apart *before* entry, though, would they become just a large meteor shower? Or would they become an unpredictable shower of meteors that are each capable of destroying a small town?


"I guarantee you that at some point, everything's going to go south on you, and you're going to say, 'This is it, this is how I end.' Now you can either accept that, or you can get to work." - Mark Watney

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#183 2016-05-29 07:48:08

Tom Kalbfus
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Re: The SLS: too expensive for exploration?

Terraformer wrote:

If the bodies could be blown apart *before* entry, though, would they become just a large meteor shower? Or would they become an unpredictable shower of meteors that are each capable of destroying a small town?

It would still be the same mass hitting the Earth. usually they say a meteor shower would be much worse than a single meteor. It would be hard to blow an asteroid completely to dust or to a glowing plasma which is what you might need.
crater-1_wide-80df644b46af30e54079a7b122d55bf28f3a2378_t614.jpeg?a3ca5463f16dc11451266bb717d38a6025dcea0e
I think if this asteroid were completely vaporized before hitting the Earth, it might have saved the dinosaurs, but we would need for the gas cloud to expand by a certain amount prior to impact, because it would have the same mass, and it would dump the same amount of kinetic energy into the Earth unless part of it misses! Just think about how much energy you would need to completely vaporize this sucker though!

Last edited by Tom Kalbfus (2016-05-29 07:49:11)

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#184 2016-05-29 08:27:52

RobertDyck
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Re: The SLS: too expensive for exploration?

The K-T boundary is a layer of dirt or rock between the "Cretaceous" and "Tertiary" periods of history. I think the German word for Cretaceous starts with "K". But the K-T boundary is characterized by a strong concentration of iridium, a metal in the platinum group. Its very rare here on Earth. It indicates the asteroid was a metal asteroid. About 70% of asteroids in near-Earth space are carbonaceous chondrite, about 4% are metal, the remainder are stone. This one was about 6 miles in diameter, perhaps a little more, and metal. That is the most difficult asteroid to deflect or destroy. If you used a nuke, it would become multiple chunks a mile or more in diameter, and many smaller pieces. That could do more damage.

Of course fiction can have great fun with this. Big asteroids are rare, metal asteroids are rare, a big metal asteroid is very rare. Coincidence? Was this a dooms day weapon in a war: hadrosaur vs velociraptor?

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#185 2016-05-29 09:58:25

GW Johnson
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Re: The SLS: too expensive for exploration?

To answer Terraformer's question in post 182 above:  it depends upon two things.  (1) Do you have weapons that can break it up?  (2) How far ahead of impact can you reach it?

(1) There is no blast wave in vacuum,  there is only very bright "light" from a nuclear bomb.  You don't "blow anything up".  That light shining on a surface vaporizes some of the surface,  creating a momentum reaction to the spalling.  On an unconsolidated body,  if close and bright enough, the force of the bright light could easily disrupt the body.  How bright and how close are wide-open questions,  because we do not yet understand what the cohesive forces really are.  On those bodies which truly are solid,  you can push it around without breakup.  It works just like simple momentum impactors,  just a whole lot bigger and hotter in effect. 

Bottom line:  we do not yet know enough about the physical/mechanical properties of these things to know whether a nuke would tear apart any given small body or not.  There seems to be no specific set of characteristics to hang your hat on,  instead there seems to be a very wide spectrum of differing properties.  All is very poorly characterized from an engineering viewpoint. 

(2) If you disrupt the body years in advance,  the fragments spread in space about and along the orbital trajectory,  so that the entire meteor swarm does not strike the Earth,  only part of it does.  It's still a shotgun blast,  but the mass hitting you can be much smaller than the original object.  If you do this up close,  like days to months,  the fragments do not have time to spread out significantly.  You get hit by the entire mass,  now as a shotgun blast instead of a point strike. 

Bottom line:  don't do the breakup thing close in,  because the shotgun blast is likely more damaging than the single-point strike. 

As for the effects of fragment size,  think 1+ km = extinction event or close too it.  Think 100+ m regional total destruction.  Think 10+ m = major city buster like a megaton-range nuke,  Think 1+m = small city buster more like Hiroshima and Nagasaki. 

As I have said before,  where these things explode depends upon how consolidated they are,  what angle trajectory they enter, and how massive they are.  Truly solid rocks or pieces of metal will lose roughly 1/8 inch radius due to ablation,  and reach the surface.  That means 1/4+ inch gravel really does land.  The others explode in the air on the way down,  and are termed "bolides". 

Chelyabinsk was one of these unconsolidated bolide things about 10 m in size roughly.  It exploded as high as it did,  only because the entry angle was as shallow as it was.  Tunguska was something similar. 

As a rule of thumb,  velocity at entry interface for these things is crudely 37 miles/sec (59 km/s).  The energy of the blast corresponds roughly to object kinetic energy,  whether a bolide or a surface impact.  But for bolides,  momentum is also conserved.  Totally unlike nuclear explosions,  the fireball of a bolide is still moving down the trajectory at astronomical speeds.  What that means is this:  the explosion might happen high up,  but things on the ground down-trajectory can still be incinerated by the fireball after the explosion.  The fireball can even impact the ground in some cases.

If you don't believe me,  then contact Stan Boslough at Sandia Labs.  He's the world expert in this area.  I met him and got to talk to him for quite a while at the 2009 asteroid deflection conference in Granada.  That moving fireball thing was quite a shock to the community at that time.  Not so much now.  Not after Boslough's presentation at that meeting. 

BTW, our ICBM's are incapable of reaching escape speed while carrying the nukes.  Nor do they have the guidance and targeting capability for an asteroid intercept.  Same is true of Russia's,  and the rest. 

The approach so far has been (1) do the detection surveys to find out who is a threat as a function of size (they're down to around 200 m in size now,  but the effort is very incomplete),  and (2) start building the international networks for warning and disaster recovery.  Doing the deflection developments seems to be taking a back seat to those two considerations,  for now.  The nearest-term technology is the simple momentum impactor,  for use on long lead-time problems.  Its competitor is the gravity tractor approach.  For the short-term/last ditch defense scenario,  there are only nukes,  but rockets capable of getting them there.  Yet. 

GW

Last edited by GW Johnson (2016-05-29 10:11:42)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#186 2016-05-29 13:10:34

Tom Kalbfus
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Re: The SLS: too expensive for exploration?

You are concentrating on a Hollywood style, last minute deflection, after an asteroid is confirmed to be on a collision course with the Earth, and if you will excuse me, the whole idea is just plain stupid!
asteroid_orbit_map_detail.jpg
This is a map of the orbits of asteroids we have got to worry about, none of them has been detected to be on an immediate collision course with Earth, but you notice that a lot of these orbits do cross Earth orbit, many of them will someday collide with Earth, we don't know which ones, so I suggest we get rid of them all, mine them all out of existence as soon as we can, and once the area around Earth orbit is cleared, we don't have to worry about them anymore. I think many of them can be redirected to Orbit Earth, Mars or Venus, put them in nice safe orbits, and they won't threaten Earth!

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#187 2016-05-29 13:13:43

Tom Kalbfus
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Re: The SLS: too expensive for exploration?

RobertDyck wrote:

The K-T boundary is a layer of dirt or rock between the "Cretaceous" and "Tertiary" periods of history. I think the German word for Cretaceous starts with "K". But the K-T boundary is characterized by a strong concentration of iridium, a metal in the platinum group. Its very rare here on Earth. It indicates the asteroid was a metal asteroid. About 70% of asteroids in near-Earth space are carbonaceous chondrite, about 4% are metal, the remainder are stone. This one was about 6 miles in diameter, perhaps a little more, and metal. That is the most difficult asteroid to deflect or destroy. If you used a nuke, it would become multiple chunks a mile or more in diameter, and many smaller pieces. That could do more damage.

Of course fiction can have great fun with this. Big asteroids are rare, metal asteroids are rare, a big metal asteroid is very rare. Coincidence? Was this a dooms day weapon in a war: hadrosaur vs velociraptor?

Iridium is a rare and precious metal, imagine how much money could have been made by mining that asteroid rather than by letting it hit the Earth and kill all the dinosaurs, I'll bet you their are a bunch of asteroids now out there like that K-T asteroid just waiting to be mined, or we can ignore them and wait for them to hit Earth.

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#188 2016-05-29 13:51:21

RobertDyck
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Re: The SLS: too expensive for exploration?

I've argued to not move asteroids. The mining industry here on Earth can move mountains. They don't move a mountain to the outskirts of a city and mine there, they mine in place. They can move a mountain one truckload at a time. Mine the asteroid in place where it is. If it's solid metal, you will end up mining it out of existence. Bring precious metals back to Earth: gold, silver, platinum, and platinum group metals. Make an aeroshell (heat shield & back shell) out of nickel and chrome from the rest of the metal. Inconel 617: 44.5%+ nickel, 20-24% chrome, 10-15% cobalt, 8-10% molybdenum, 0.8-1.5% aluminum, 0.05-0.15% carbon. Could have small traces of some other metals. Drop the aeroshell on a desert on Earth somewhere, loaded with precious metal bullion. No parachute, no air bag, no thrusters, no control. Just drop a shaped hunk of metal, tell everyone to stay out of the way. You could either park residual metal at the asteroid, or transport it some place in space more safe, and where it could be used later.

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#189 2016-05-29 14:04:08

GW Johnson
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From: McGregor, Texas USA
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Posts: 4,078
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Re: The SLS: too expensive for exploration?

Tom,  I wish you would learn to read with your filters removed for once.  Everything I wrote points explicitly toward long lead time deflection as the better choice. 

How could what I wrote in post 185 above possibly be interpreted as "You are concentrating on a Hollywood style, last minute deflection, after an asteroid is confirmed to be on a collision course with the Earth, and if you will excuse me, the whole idea is just plain stupid!"?  No one in their right mind with a lick of common sense would read what I wrote,  and come to a conclusion like that. 

Now as to deflecting 10-100 m size bodies into "safe" orbits,  what you propose and what we might actually achieve over the next half a century are light years apart.  The technology to do what you want we simply do not have,  and won't for a very long time yet. 

The kinds of deflections we can achieve with impactors and gravity tractors are measured in cm/s sec change to an astronomical speed measured in km/sec.  That only has a measurable effect if done very, very far from perihelion.  Nothing "last-minute" about that. 

But you do have to pick your targets.  Pareto's Principle says deal with the ones that might hit you first.  Anything else is a premature waste of resources just to get there.  Going after all of them at this time in history is an asininely-stupid idea. 

Deflections with nukes closer in are not much better,  maybe a m/s sec out of 10's of km/s.  If it doesn't break up instead.  That is the "last minute" problem.  What I wrote says we cannot yet do it,  because we do not yet have the right rocket and spacecraft guidance hardware.  We could,  but no one is working on it.

The only thing that you wrote that makes any sense at all is mining the things for precious metals.  That could pay off,  perhaps.  But at first,  we can only reach a handful,  and mining does not require deflection. 

Even NASA recognizes that the only ones we can bring into cis-lunar space are under 1 m in size.  Look at their asteroid redirect mission plans.  They want to put a very tiny one,  or even just a small rock off a larger one,  in a baggie and bring it home.  And they have yet to define the spacecraft that might do this,  much less the rocket to launch it.

Those outfits interested in mining are further along than NASA,  in many ways.  At least the spacecraft are starting to be defined,  as well as the mining extraction methods.  One of the most promising has to do with decomposing it thermally by shining a very bright light on it inside a big plastic bag.  This is also restricted to objects under a meter in size,  so far. 

The orbits you had in the exciting plot are for the first generation survey.  That's the ones bigger than 1 km in size.  They are just getting started finding the ones nearer 100 m.  Very few as yet have been found since we do not yet have in place the hardware to find them.  There's as yet almost no success at all finding things 10 m or less,  except at a day or two to impact.  Sometimes.  Only sometimes. 

GW

Last edited by GW Johnson (2016-05-29 16:28:56)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#190 2016-05-29 17:12:11

Tom Kalbfus
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Posts: 4,401

Re: The SLS: too expensive for exploration?

RobertDyck wrote:

I've argued to not move asteroids. The mining industry here on Earth can move mountains. They don't move a mountain to the outskirts of a city and mine there, they mine in place. They can move a mountain one truckload at a time. Mine the asteroid in place where it is. If it's solid metal, you will end up mining it out of existence. Bring precious metals back to Earth: gold, silver, platinum, and platinum group metals. Make an aeroshell (heat shield & back shell) out of nickel and chrome from the rest of the metal. Inconel 617: 44.5%+ nickel, 20-24% chrome, 10-15% cobalt, 8-10% molybdenum, 0.8-1.5% aluminum, 0.05-0.15% carbon. Could have small traces of some other metals. Drop the aeroshell on a desert on Earth somewhere, loaded with precious metal bullion. No parachute, no air bag, no thrusters, no control. Just drop a shaped hunk of metal, tell everyone to stay out of the way. You could either park residual metal at the asteroid, or transport it some place in space more safe, and where it could be used later.

The difference is on Earth the real estate is fixed, with an asteroid moving in a separate orbit, you will have to deal with launch windows when shipping your mining product to Earth or where ever its needed, and with Near Earth orbit, these launch windows are very infrequent. It might be tempting to move an asteroid into Earth orbit and then mine from there.

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#191 2016-05-29 17:22:04

Tom Kalbfus
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Re: The SLS: too expensive for exploration?

GW Johnson wrote:

Tom,  I wish you would learn to read with your filters removed for once.  Everything I wrote points explicitly toward long lead time deflection as the better choice. 

How could what I wrote in post 185 above possibly be interpreted as "You are concentrating on a Hollywood style, last minute deflection, after an asteroid is confirmed to be on a collision course with the Earth, and if you will excuse me, the whole idea is just plain stupid!"?  No one in their right mind with a lick of common sense would read what I wrote,  and come to a conclusion like that. 

Now as to deflecting 10-100 m size bodies into "safe" orbits,  what you propose and what we might actually achieve over the next half a century are light years apart.  The technology to do what you want we simply do not have,  and won't for a very long time yet.

 
The next half century is from 2016 to 2066, the previous half century was from 1966 to 2016. In 1966 we were doing Gemini., computers were primitive things.

In his new book, “Superintelligence: Paths, Dangers and Strategies,” Nick Bostrom, director of the Future of Humanity Institute at Oxford University, lays out a range of predictions from the top artificial intelligence (AI) researchers in the field.

Computers to compete with a human brain by 2020

His work, reported in Bloomberg, suggests a 10 percent probability computers become as intelligent as humans by the year 2020, with a 50 percent probability by 2040 and a 90 percent probability computers attain human intelligence by the year 2075.

http://www.valuewalk.com/2014/11/comput … uman-mind/

If our puny little brains can't figure out how to deflect an asteroid, maybe theirs will.

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#192 2016-05-29 17:31:26

RobertDyck
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From: Winnipeg, Canada
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Re: The SLS: too expensive for exploration?

Tom Kalbfus wrote:

It might be tempting to move an asteroid into Earth orbit and then mine from there.

Or better yet, on the ground. Easy to reach, no rockets at all. Say a 6 mile diameter metal asteroid, just splash it down in the ocean, somewhere we can already harvest resources. Say the Gulf of Mexico just north of the Yucatan peninsula.

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#193 2016-05-29 18:46:15

GW Johnson
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From: McGregor, Texas USA
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Re: The SLS: too expensive for exploration?

Tom:

Don't be silly.  Computers can only do what we program them to do.  We can only program them to do what we know about. 

Therefore, there is no way in hell a machine can "figure out" how to do something that a human cannot figure out or does not know about. 

Simple as that.  Doesn't matter what somebody writes in a book to make money. 

GW

Last edited by GW Johnson (2016-05-29 18:47:41)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#194 2016-05-31 08:18:49

Tom Kalbfus
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Re: The SLS: too expensive for exploration?

GW Johnson wrote:

Tom:

Don't be silly.  Computers can only do what we program them to do.  We can only program them to do what we know about. 

Therefore, there is no way in hell a machine can "figure out" how to do something that a human cannot figure out or does not know about. 

Simple as that.  Doesn't matter what somebody writes in a book to make money. 

GW

Depends on what sort of computers they are, and what we programmed them to do. We can for instance program them to simulate the human brain, or we can build computers with circuitry designed to emulate the human brain. We have made some progress in that field. I have a hand held device that when I speak into it, it interprets my spoken words and writes text, it is a GPS app, I say a address, and it finds directions from where I'm at to the destination, and it works most of the time. There are also computers that drive cars. Computers are becoming more and more capable, soon they will be able to do all our work, including the work of scientists and engineers, because in reality, there is not much difference in computing power between the dumbest humans and the smartest. Today's computers are as smart as some lower animals.

https://en.wikipedia.org/wiki/Blue_Brain_Project

http://homes.cs.washington.edu/~diorio/ … EEComp.pdf

http://www.artificialbrains.com/

http://www.bbc.com/future/story/2013020 … -the-brain

And there is Moore's Law.

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#195 2016-05-31 09:01:48

GW Johnson
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Posts: 4,078
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Re: The SLS: too expensive for exploration?

"Today's computers are as smart as some lower animals."  -- no,  they are NOT.  They only appear to be.  Appearances are deceiving!  Very,  very deceiving!  That leads to hype and nonsense and self-deception on our part,  not fact. 

All (and I do mean ALL!!!) of today's computer technology is based on the original Von Neumann architecture from over half a century ago,  which is aimed only at doing arithmetic calculations efficiently,  with a three-level hierarchy of memory. 

What goes on in a biologic brain (of ANY) size,  is quite different.  And it is NOT yet understood well enough to imitate or replicate yet,  not by a long shot. 

Until we have an architecture,  and the technology and hardware to support it,  that resembles biologic brains,  there is really no such thing as "artificial intelligence" that can truly learn and deal with the unexpected.  What we have now only "learns" by adding new things to the database it uses to execute its program. 

As I said,  appearances are quite deceiving.  These things can fool us into believing they think like us,  but in fact they do not.  They ONLY run stored data through a program to calculate pre-programmed results.  They do not change the programming,  they only add to the database they have.  That is all that they can do. 

GW

Last edited by GW Johnson (2016-05-31 09:04:08)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#196 2016-05-31 13:19:30

Tom Kalbfus
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Re: The SLS: too expensive for exploration?

Have you gone to any of the websites I indicated? I've seen computers do more and more of the kind of jobs that people used to do. I'm quite shocked that when I speak into a computer, it produces a grammatically correct sentence conveying the meaning I intended. When you ask Siri a question and it knows where to look, that is artificial intelligence. I believe they simulated the brain of a tapeworm, I believe computers are as smart as insects, I think they even did a rat brain, and their are robots that walk, run and fly without human direction. But every time a computer makes an advance, there are people like you who discount them, they have an explanation for every time a computer takes away someone's job. But I guess the expectation is that scientists are some how different from waitresses, and assembly line workers, and that somehow a scientist's job will never be automated, as they are the only members of the human race that actually think. When I visit a hospital, the bill is expensive, wouldn't it be nice to have a fully automated hospital, a computer that makes diagnoses, and performs surgery. Wouldn't it be nice to have a fully automated rocket factory and launch facility, that way space travel would be so much cheaper? Things are expensive because of their high human labor content, the Apollo program was expensive precisely because of how many people it employed to launch just one rocket. that is the problem with human spaceflight, so much labor to get so little done! All these human beings working on concert to get a relative handful of people into space, that has got to change!

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#197 2016-05-31 15:00:07

GW Johnson
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From: McGregor, Texas USA
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Re: The SLS: too expensive for exploration?

Tom: 

You really made my point in your second and third sentences above:  you've been deceived by the appearance of intelligence in machines,  in the sense that we use that word intelligence for people and animals.  What these things have been programmed to do is quite impressive,  but it's programming,  nothing more. 

Until the information-processing architecture is something other than a Van Neumann adding machine,  it can never be any more than a very sophisticated set of programming instructions inside a fancy calculator with a lot of hierarchical memory.  It cannot be programmed for things the programmer does not know about.  Nor can it learn more techniques for processing data than the programmer knew.  It can only add to its database,  and perhaps respond more "intelligently" as that database expands. 

The fundamental limitation is no different than it was circa 1960.  Only the sophistication and speed of the design has changed. 

GW


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#198 2016-05-31 15:53:24

RobertDyck
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Re: The SLS: too expensive for exploration?

The joint Senate-NASA presentation for SLS was September 2011. It's now 4 years 8 months and an odd number of days. Saturn C5 was announced January 10, 1962. Apollo 4 was the first test flight, November 9, 1967. That was 5 years and 10 months later. Ignoring all the time and money spent on Ares V under Constellation, SLS will have spent the same time in July 2017. SLS is supposed to be built upon technology and infrastructure from Saturn V and Shuttle, it's supposed to take less time and money. It isn't scheduled to launch until November 2018.

Frustrated!

Last edited by RobertDyck (2016-05-31 20:32:52)

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#199 2016-05-31 19:06:53

SpaceNut
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Posts: 19,699

Re: The SLS: too expensive for exploration?

Yes it is Frustrating to see this occuring and there appears little other than more cash that can solve the issue or not.....
One can only hope that once it flies that it can stand up to the hype as I am seeing that its not unless more money is poured into it....

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#200 2016-06-01 09:24:45

GW Johnson
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From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 4,078
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Re: The SLS: too expensive for exploration?

All those billions spent on a giant rocket years late in flying (if it ever does) and a capsule too heavy to use for anything.  For an agency whose top management get their objectives dictated to them by congress,  changing radically with every administration. 

So,  what else did you realistically expect? 

You have had until last year a monopoly contractor (ULA) who serves only one customer (the US government in the form of USAF and NASA),  working on things dictated by a brain-dead congress,  in a giant corporate welfare system that has built up continuously since during World War 2,  to the point now where the giant contractor need do nothing anymore to still get the money.   

With the entry of Spacex into government contracting (USAF launch authorization last year,  finally),  and the foreign companies and Spacex competing with ULA for the commercial business,  we're starting to see a little beneficial change. 

Commercially,  what is offered is "here's my rocket,  here's what it can do,  here is how much it will cost you to launch one".  That sometimes gets complicated by more than one customer sharing the ride,  just like in the taxicab business. 

They do not change their rockets to fit your payload,  you have to design your payloads to fit their rockets.  If they perceive real interest in larger payloads,  by tracking inquiries about it,  then eventually they build bigger rockets to meet the demand.  All is working just like it should.  That's the market in action. 

Now,  redesigning your oversize payloads to fit their rockets may seem inconvenient,  but it is really not,  if you choose a mission design that is inherently flexible.  Launching things assembled by docking in LEO to distant destinations,  instead of one-shot direct-trajectory launches on giant rockets, is exactly what I am talking about. 

It does require jettisoning preconceived notions and quitting old bad habits to do this.  I see lots of resistance to that,  just like we see lots of resistance to quitting smoking. 

You can use bigger tinkertoys when the bigger rockets come along,  so keep on asking for them,  and eventually they will appear.  Until then,  just use smaller tinkertoys.  It really is that simple.  And when your bigger rockets do come along,  you do not necessarily have to redesign your smaller tinkertoys.  Just launch more than one of them at a time on the bigger rocket.  You still save money. 

And that flexibility (in both what you can design,  and what rocket it can ride) is one of the several compelling reasons that I keep proposing orbit-to-orbit mission designs for Mars,  the other planets,  and the asteroids. 

Lack of a giant rocket is no credible excuse not to go.  It never has been. 

Example:  if there never had been a Saturn-5,  we still could have sent Apollo as we finally knew it to the moon with Saturn-1's.  It would have taken 4 or 5 Saturn-1 launches to assemble in LEO a cluster equivalent to the Apollo CSM plus a LM,  plus an equivalent to a partially-fueled S-IVB stage.  You solve the too-heavy Apollo cluster problem the same way with the same lunar rendezvous and docking that we did.  You solve the too-small-a-launch rocket problem by doing docking assembly in LEO.  Apollo staged out of LEO anyway,  just for trajectory control purposes. 

GW

Last edited by GW Johnson (2016-06-01 09:40:09)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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