http://www.space.com/scienceastronomy/060620_science_tuesday.html
fragments remaining after the use of such strategy.
I've been reluctant to support moving asteroids around for mining, but, if
there's anything to this idea, it could be a side thing to the mining.. a
complement of sorts.
cygo.com
Just to mention, I've added a new chat system at cygo. Rooms created will
not expire there. And they can be public or private.
http://cygo.com/chat
On 6/20/06, Lucio de Souza Coelho wrote:
--- In spacesettlers@yahoogroups.com, "Lucio de Souza Coelho"
wrote:
>
> http://www.space.com/scienceastronomy/060620_science_tuesday.html
>
> Interesting, though I think that there would be a lot of kiloton-
power
> fragments remaining after the use of such strategy.
>
it would depend on the angle and position of impact, realitive
speeds, distance out when they impacted, and size of objects.
course, at a small angle, several times the distance the moon is
from the earth, the smaller one would be destroy, leaving a few
pieces headed to earth while the larger one would be mostly intact,
but would be deflected enough to miss the earth. a small amount would
be thrown out along the original path. most would be destroy by the
heat of the atmosphere, while many would impact, but be too small to
do much damage. a few that could do serious damage would be left, but
they might miss the earth or the might hit but do little damage (a
hit in a desert would do some residual damage, but little immeadiate).
example two. again far out. moving in opposite direction. speed of
the small one, about 18 miles a second, speed of the large one, 14
miles a second (relative to earth). impact is to the side of the
larger one in the direction of earths travel). the smaller one would
be completely destroyed, headed in all direction. the larger one
would have a large amount destroyed, again going in all directions,
mostly away from earth. the remain large chunk would pass behind the
earth. some pieces of it would hit the earth, most likely nothing big.
if they hit near earth, there is little that can be done to keep a
large amount hitting the earth, some will be big. again the size that
hits will be determined by the angle, relative size, relative speed
and part of the larger one struck.
Yes.
You can't just spit on the big ones and expect them to run away.
George
cygo.com
On 6/21/06, Robert wrote:
it would sure take a lot of computing to work out the details, but the
main point is, it would be better to allow a few small nuclear size
hits which would not kill everyone, than to allow one hit that would
take out the entire human race. man could recover from a loss of our
civilization, even if we were knocked back to the stone age, but we
would not be able to survive a hit like the one in south america.
On 6/22/06, Robert wrote:
(...)
> it would sure take a lot of computing to work out the details, but the
> main point is, it would be better to allow a few small nuclear size
> hits which would not kill everyone, than to allow one hit that would
> take out the entire human race. man could recover from a loss of our
> civilization, even if we were knocked back to the stone age, but we
> would not be able to survive a hit like the one in south america.
(...)
place in nowadays Mexico, which is considered part of *North* America.
Anyhow, I think that Humanity (or rather a tiny fraction of it)
*could* survive another KT event. All you need is to stuff a big
cavern with lots of supplies and a few thousand people, and let them
locked in there for some years until dust settles and the sun starts
to shine again.
The problem with poor dinosaurs was that they could neither forecast
nor plan for catastrophes.
--- In spacesettlers@yahoogroups.com, "Lucio de Souza Coelho"
wrote:
>
> On 6/22/06, Robert wrote:
>... like the one in south america..
>
> Being picky again: if you are talking about the KT Event, it took
> place in nowadays Mexico, which is considered part of *North*
America.
>
> Anyhow, I think that Humanity (or rather a tiny fraction of it)
> *could* survive another KT event. All you need is to stuff a big
> cavern with lots of supplies and a few thousand people, and let them
> locked in there for some years until dust settles and the sun starts
> to shine again.
>
> The problem with poor dinosaurs was that they could neither forecast
> nor plan for catastrophes.
>
that assumes that humans are any better at forseeing disaster and
planning for it. im afraid our track record is not that great in this
area.
cygonaut wrote
> I've been reluctant to support moving asteroids around for mining, but,
>if
>there's anything to this idea, it could be a side thing to the mining.. a
>complement of sorts.
Just for curiosity, What's your objection to moving them around for mining?
That article seems tabloid shallow, hollywood fake, and puerile as anything
else about this topic in the mainstream media. A variant of "just send up a
nuke to blow it up". Never mind that there's a billion and one problems with
stating it that simply.
I may be completely wrong, but it seems like the two goals (mining and
planetary defense) go together well. We need to have a large space-based
observation capability to see them a lot better than we do today, and to
really do anything about an incoming threat, we ned to have a manned space
transportation infrastructure that lets people go to the threat like it was
any other mining target and completely survey it.
Various plans to deflect a threat all fall short because we won't know the
thing's internal consistency. Any plan requires us to know how it will
react, and the best way to affect this particular asteroid in the desired
way, and that means people moving around it for a long time. This isn't
something that can be done via telescope from a few AU away or even rovers
being teleoperated from a few AU away.
So mining and deflecting it start the same, and up until you've changed its
speed or direction a bit, they're the same. Deflecting it stops there,
because changing it a bit to avoid the Earth is all you need, while mining
it requires keeping the rockets firing a lot longer.
Very little difference in a mission sent to one to mine it or to deflect it.
You need everything the same, and actually the most fool-proof deflection
scenario is a slow rocket burn using the asteroid's mass as reaction mass
(ices or rock dust), and that's identical to a mining/retrieval. It works
equally for any type. Some might use different ISRU "rockets" depending on
whether you want to throw ices or rock dust, but rock dust through a mass
driver is always a safe bet.
The best thing we can do for planetary defense is to get out there and mine
the NEAs / Earth crossers. These are the most likely to hit us, and also the
easiest to reach for mining and the easiest to bring back either the entire
thing (what survives the particular "ISRU rocket" we're using) or packages
of mined materials.
The two aims are identical, except for mining/retrieval, we want to bring it
or bits of it controllably back to HEEO (or where the space manufacturing
facility is).
OK, I probably am wrong, but it seems to this ignorant person that if you're
going to the effort to deflect it from hitting the Earth, you might as well
send the extra equipment to make it a retrieval, which brings it back to eat
it up for resources.
--- In spacesettlers@yahoogroups.com, "John Frazer"
>
> cygonaut wrote
> > I've been reluctant to support moving asteroids around for
mining, but,
> >if
> >there's anything to this idea, it could be a side thing to the
mining.. a
> >complement of sorts.
>
> >http://www.space.com/scienceastronomy/060620_science_tuesday.html
>
> Just for curiosity, What's your objection to moving them around for
mining?
>
> That article seems tabloid shallow, hollywood fake, and puerile as
anything
> else about this topic in the mainstream media. A variant of "just
send up a
> nuke to blow it up". Never mind that there's a billion and one
problems with
> stating it that simply.
>
> I may be completely wrong, but it seems like the two goals (mining
and
> planetary defense) go together well. We need to have a large space-
based
> observation capability to see them a lot better than we do today,
and to
> really do anything about an incoming threat, we ned to have a
manned space
> transportation infrastructure that lets people go to the threat
like it was
> any other mining target and completely survey it.
> Various plans to deflect a threat all fall short because we won't
know the
> thing's internal consistency. Any plan requires us to know how it
will
> react, and the best way to affect this particular asteroid in the
desired
> way, and that means people moving around it for a long time. This
isn't
> something that can be done via telescope from a few AU away or even
rovers
> being teleoperated from a few AU away.
> So mining and deflecting it start the same, and up until you've
changed its
> speed or direction a bit, they're the same. Deflecting it stops
there,
> because changing it a bit to avoid the Earth is all you need, while
mining
> it requires keeping the rockets firing a lot longer.
> Very little difference in a mission sent to one to mine it or to
deflect it.
> You need everything the same, and actually the most fool-proof
deflection
> scenario is a slow rocket burn using the asteroid's mass as
reaction mass
> (ices or rock dust), and that's identical to a mining/retrieval. It
works
> equally for any type. Some might use different ISRU "rockets"
depending on
> whether you want to throw ices or rock dust, but rock dust through
a mass
> driver is always a safe bet.
>
> The best thing we can do for planetary defense is to get out there
and mine
> the NEAs / Earth crossers. These are the most likely to hit us, and
also the
> easiest to reach for mining and the easiest to bring back either
the entire
> thing (what survives the particular "ISRU rocket" we're using) or
packages
> of mined materials.
> The two aims are identical, except for mining/retrieval, we want to
bring it
> or bits of it controllably back to HEEO (or where the space
manufacturing
> facility is).
>
> OK, I probably am wrong, but it seems to this ignorant person that
if you're
> going to the effort to deflect it from hitting the Earth, you might
as well
> send the extra equipment to make it a retrieval, which brings it
back to eat
> it up for resources.
>
i agree whole heartedly.
Generally, asteroids have the consistancy of hard packed snow. We know this
from observing a crater erasing effect from an impact. The asteroid
vibrated when impacted and, as a result, many craters vanished.. erased
away. This event also altered the math/science of determining how old
asteroid craters and the asteroids themselves are. Let's just say this
field has become mirkier than ever - lol.
equipment.
Moving an asteroid to avoid impact with earth is simple. You just evaporate
any point on its surface using heat directed by a mirror which can be made
of aluminum foil or other light and reflective material. "Outgassing" moves
the "rock". All you need is to move it a tiny bit and it'll miss the earth
completely.
On retrieving an asteroid, rocketry will have to be very slow to start and
your will need rocket to slow it down and stop it. Some experimenting is
needed and computerization, no doubt.
I want more input from engineers on the retrievability and relocatability of
an asteroid, and a clear idea how earth's leadership might respond before I
give it my full support. In any event, if earth says "no" we need the
back-up plan.
George
cygo.com
On 6/23/06, John Frazer wrote:
--- In spacesettlers@yahoogroups.com, cygonaut
>
> Moving an asteroid to avoid impact with earth is simple. You just
evaporate
> any point on its surface using heat directed by a mirror which can
be made
> of aluminum foil or other light and reflective
material. "Outgassing" moves
> the "rock". All you need is to move it a tiny bit and it'll miss
the earth
> completely.
the earth is(approximately) 42 million feet in diameter. that means
if you have a good idea of where it might hit (say north or south,
front or back half of the planet) you would have to move its path a
max of 21 million miles in one direction or another for it to
completely miss the earth. If you have a year warning and can put the
motor there within 4 months, you would have to move the object from
its path an average of one foot per minute. if the object is 1
million tones, and you have about 8 months, it would take about 100
foot pounds per second to move it. that is something with in the
capacity of a mirror powered motor.
alternately, since the earth moves through a set spot in its orbit
(the point of impact) in less than 166 seconds, accelerating or
decelerating the asteroid a matter of 3 inches per second, meaning it
could be done in less time.
the problem arises in the the object is spining and tumbling, so that
has to be stopped before you can begin to alter its path, without
breaking it up.
>
> On retrieving an asteroid, rocketry will have to be very slow to
start and
> your will need rocket to slow it down and stop it. Some
experimenting is
> needed and computerization, no doubt.
>
> I want more input from engineers on the retrievability and
relocatability of
> an asteroid, and a clear idea how earth's leadership might respond
before I
> give it my full support. In any event, if earth says "no" we need
the
> back-up plan.
>
> George
> cygo.com
the problem with trying to retrieve an asteroid (bringing it into
earths orbit) is that the to can be very different in their relative
speed.
im not an expert on it, but ive heard that the objects cross our path
at a relative speed of about 14 miles per second. earths gravity
means that the orbital speed of an object (relative to earth) is less
than 7 miles per second. this means you have to change the relative
speed by about 7 miles per second (or more) for earth to capture it.
it might be possible to use the moon to help (possible even using the
earth gravity to slow it too). this would likely put it our of reach
of a simple out gassing motor. perhaps an electromagnitic system,
perhaps a very large ionic system, using the asteroids material. ion
engines can acclerate the material several hundred miles a second,
meaning that compairatively little of the astorids material would be
lost.
--- In spacesettlers@yahoogroups.com, "Robert" wrote:
>
> > I want more input from engineers on the retrievability and
> relocatability of
> > an asteroid, and a clear idea how earth's leadership might respond
> before I
> > give it my full support.
asteroids was the same the initial atomic bomb scientists had about
their 'baby', the malevolent use such abilities would one day be put.
I find it hard to dismiss the fear that once the ability to move
asteroids becomes as widespread as the current ability to make nuclear
explosives nations with predatory or religiously fanatical agendas
will direct asteroids towards terrestrial targets, asteroids large
enough to dwarf most nuclear explosives but small enough not to cause
a mass extinction event. If we didn't want terrorists to have the bomb
we never should have developed them in the first place. So it may be
with the ability to guide the path of small asteroids for good or for ill.
Don
I would place it in the L5 moon-earth LaGrange point for mining, processing,
and construction if I moved one. Otherwise it's stuff processed and made at
the asteroid site and all you can carry to the L5 point and stockpiling,
processing, and more construction there, as well as shipping materials and
finished products to earth, some directly and some from L5. But we can
build the vehicles we need at the asteroid too, installing, at first, needed
light weight components launched from earth. Later we make most everything
ourselves, of course.
Part of Sagan's (and others) concern is that the consequences of any
asteroid mishap could be catastrophic. You don't get an opportunity
to perfect your technique. You have to be perfect the first time. A
mistake could kill millions or billions, dwarfing Chernobyl or Three
Mile Island. And we make tons of mistakes. We could, I suppose
practice placing asteroids around Jupiter or Mars or something first,
but committees here on Earth would probably vote that down as a waste
of money that could be spent building pork-barrel projects here on
Earth in committee members' Congressional districts.
vastly different religious and moral views in space, as on Earth, and
therefore there is the risk of some space settlement arising that
hates the Earth for it's moral decadence. If such a society could
gain control of Asteroid moving technology, they could theoretically
wipe us out. Personally, I'm skeptical that a fanatical society will
be able to operate a colony successfully for at least the next couple
of hundred years. I can't imagine well financed governments here on
Earth allowing anyone else that kind of control. Security against
asteroids and nukes and such will be a prime reason, but also the
rich governments and the big corporations they control will want any
profits that come from zero G manufacturing and asteroid mining.
On a different note: Just read that the Hubble telescope has gone
offline. The decision's already been made to abandon it next year, so
if they can't reboot it, it's probably dead for good.
doug
On Jun 24, 2006, at 12:22 PM, Don Davis wrote:
> From: Douglas May
> Part of Sagan's (and others) concern is that the consequences of any
> asteroid mishap could be catastrophic.
retrieval' specify *pieces* of asteroid about a hundred meters across for
the reason that rocks this 'small' would burn up before hitting ground
level.
Besides, wouldn't they be *breaking* into earth orbit? If the engines fail
they don't hit the earth, they'd just pass right by.
> therefore there is the risk of some space settlement arising that
> hates the Earth for it's moral decadence.
Or religious stupidity.
> If such a society could
> gain control of Asteroid moving technology, they could theoretically
> wipe us out.
The colony might be at the top of our gravity well, but it would be
dependent on so many other facilities to pose any serious threat to Earth.
Even if all of the facilities rebelled at once Earth would still dwarf their
industrial capacity. Given the time and effort involved to move an asteroid
we could probably build warships from scratch and have them at their door
before the planet was in serious danger.
John
the difference between the two is mobility and speed of delievery.
several parts of a suitcase bomb in the hands of a group of suicidal
bombers, even if only one is suppose to die with it, would almost be
impossible to stop, short of watching for the radioactive material,
mainly because there would be nothing except the matterial to give
someone a warning.
perhaps weeks.
--- In spacesettlers@yahoogroups.com, "Don Davis"
>
> A major concern Carl Sagan had about obtaining the ability to move
> asteroids was the same the initial atomic bomb scientists had about
> their 'baby', the malevolent use such abilities would one day be
put.
> I find it hard to dismiss the fear that once the ability to move
> asteroids becomes as widespread as the current ability to make
nuclear
> explosives nations with predatory or religiously fanatical agendas
> will direct asteroids towards terrestrial targets, asteroids large
> enough to dwarf most nuclear explosives but small enough not to
cause
> a mass extinction event. If we didn't want terrorists to have the
bomb
> we never should have developed them in the first place. So it may be
> with the ability to guide the path of small asteroids for good or
for ill.
personaly id put it at l2 (far side of earth) because that is one of
the unstable ones, plus its less likely to be a risk to earth.
due to the transfer paths
(http://en.wikipedia.org/wiki/Interplanetary_Transport_Network) from
there, it would not take much energy to send it towards L5 or L4
(trojan positions) which are stable.
>
> I would place it in the L5 moon-earth LaGrange point for mining,
processing,
> and construction if I moved one. Otherwise it's stuff processed
and made at
> the asteroid site and all you can carry to the L5 point and
stockpiling,
> processing, and more construction there, as well as shipping
materials and
> finished products to earth, some directly and some from L5. But we
can
> build the vehicles we need at the asteroid too, installing, at
first, needed
> light weight components launched from earth. Later we make most
everything
the practice come in bringing it to earth: you constantly monitor
your position, and things. if they are off by a slight bit, you back
off and figure why you are not controlling it as it is suppose to be.
anyone that tries to bring the asteroid into near earth orbit first
needs to have his head examined. you start off by putting it into far
earth orbit, then gradually bringing it in closer. that way if you
fail, it just misses going into orbit, not hitting the earth. that
means no one is at risk.
>
> Part of Sagan's (and others) concern is that the consequences of
any
> asteroid mishap could be catastrophic. You don't get an
opportunity
> to perfect your technique. You have to be perfect the first time.
A
> mistake could kill millions or billions, dwarfing Chernobyl or
Three
> Mile Island. And we make tons of mistakes. We could, I suppose
> practice placing asteroids around Jupiter or Mars or something
first,
> but committees here on Earth would probably vote that down as a
waste
> of money that could be spent building pork-barrel projects here on
> Earth in committee members' Congressional districts.
>
> The debates on this list alone make it clear that there will be
> vastly different religious and moral views in space, as on Earth,
and
> therefore there is the risk of some space settlement arising that
> hates the Earth for it's moral decadence. If such a society could
> gain control of Asteroid moving technology, they could
theoretically
> wipe us out. Personally, I'm skeptical that a fanatical society
will
> be able to operate a colony successfully for at least the next
couple
> of hundred years. I can't imagine well financed governments here
on
> Earth allowing anyone else that kind of control. Security against
> asteroids and nukes and such will be a prime reason, but also the
> rich governments and the big corporations they control will want
any
> profits that come from zero G manufacturing and asteroid mining.
>
> On a different note: Just read that the Hubble telescope has gone
> offline. The decision's already been made to abandon it next year,
so
> if they can't reboot it, it's probably dead for good.
>
> doug
>
> On Jun 24, 2006, at 12:22 PM, Don Davis wrote:
>
> > --- In spacesettlers@yahoogroups.com, "Robert" wrote:
> > >
> > > > I want more input from engineers on the retrievability and
> > > relocatability of
> > > > an asteroid, and a clear idea how earth's leadership might
respond
> > > before I
> > > > give it my full support.
> >
> > A major concern Carl Sagan had about obtaining the ability to move
> > asteroids was the same the initial atomic bomb scientists had
about
> > their 'baby', the malevolent use such abilities would one day be
put.
> > I find it hard to dismiss the fear that once the ability to move
> > asteroids becomes as widespread as the current ability to make
nuclear
> > explosives nations with predatory or religiously fanatical agendas
> > will direct asteroids towards terrestrial targets, asteroids large
> > enough to dwarf most nuclear explosives but small enough not to
cause
> > a mass extinction event. If we didn't want terrorists to have the
bomb
> > we never should have developed them in the first place. So it may
be
> > with the ability to guide the path of small asteroids for good
or
You only need to nudge the asteroid for it to miss the earth completely.
For surface evaporation, you need to get to it in time.
though a blast of a nuke near the asteroid would definitely work (remember
the Orion craft experiments). Multi-megaton granade-like missiles would
probably work better. You can blast it on or near the asteroid and the
stuff inside blasts outward and gives the asteroid a push.
There will always be a need for monitoring mining operations by responsible
parties. Not only do you need to stop potential impacts with earth, they
can be intentionally sent to earth by lunatic extremists. Many also contain
Uranium (hint).
George
cygo.com
On 6/24/06, Douglas May wrote:
A balloon might be good, though they'll be some shockingly huge wind gusts.
water does.
George
cygo.com
On 6/22/06, Lucio de Souza Coelho wrote:
as far as blast time movements, i have often wondered about a group
of mininukes (smallest warhead size possible) delievered simular to
the mrv system that icbms use now. without the shielding that a
reentry vehicle needs you could put more of them in a rocket. as they
approach the target they spread out. a dozen rockets, each carrying
20 or so nukes, would cover a large area. going off simulatanously
about a hundred feet above the (nearest) surface of the asteroid,
they would send out a huge amount of energy, that would vaporize a
large chunk of the surface, spreading the "impact" over the entire.
this would decrease the likelyhood of it breaking up and would put a
tremendous amount of pressure on it to move or slow down. it could
consieveably be enough to slow it down about a mile per second.
added to the alteration in the direction, and this would be enough to
cause it to miss the earth, IF it were far enough out. alternately, a
sequense of a dozen rockets, about 100 miles behind the last, each
carrying 20 nukes, going off one after another, might do it as well.
perhaps even better.
>
> You only need to nudge the asteroid for it to miss the earth
completely.
> For surface evaporation, you need to get to it in time.
>
> For missiles, I'd stay away from nukes.. just don't need that many
megatons,
> though a blast of a nuke near the asteroid would definitely work
(remember
> the Orion craft experiments). Multi-megaton granade-like missiles
would
> probably work better. You can blast it on or near the asteroid and
the
> stuff inside blasts outward and gives the asteroid a push.
>
> There will always be a need for monitoring mining operations by
responsible
> parties. Not only do you need to stop potential impacts with
earth, they
> can be intentionally sent to earth by lunatic extremists. Many
also contain
Oh, if we could simply catch it, stick it in our pocket, and save it for a
rainy day.
.
.
(Sorry, couldn't resist.)
George
cygo.com
On 6/25/06, Robert wrote:
From: spacesettlers@yahoogroups.com
[mailto:spacesettlers@yahoogroups.com] On Behalf Of Robert
> so that has to be stopped before you can begin to alter its
> path, without breaking it up.
Actually, it occurs to me that might be an advantage to the focused
solar mirror approach. One could have a consistently vectored thrust
without first de-spinning the asteroid.
Regards,
Mike Combs
From: spacesettlers@yahoogroups.com
[mailto:spacesettlers@yahoogroups.com] On Behalf Of Don Davis
> move asteroids was the same the initial atomic bomb scientists
> had about their 'baby', the malevolent use such abilities would
> one day be put.
There was a major logical flaw in Sagan's scenario which James Oberg
pointed out. I daresay more people have read Sagan's warnings than
Oberg's rebuttal to them.
In a pre-911 era, Sagan knew people would argue that the crew sent to
the asteroid would never divert it toward the Earth, because they
themselves would be killed. Sagan's counter to this was that a madmen
might dispatch the crew with the cover story that their mission was to
prevent a collision, and then send them data which would cause them to
instead create a collision which wouldn't have occurred otherwise.
The assumption Sagan seemed to be making was that arranging a collision
and preventing one were pretty much the same operation, only with
different numbers. But being a space rendezvous expert, Oberg knew that
preventing a collision would be a matter of thrusting until one had
sufficient vector change, and then stopping. On the other hand,
arranging a collision would involve a vector change, waiting for minor
course deviations to accumulate, thrusting again to correct course, and
repeating this for most of the way back to Earth. Thus it's unlikely a
crew expecting to prevent a collision could be duped into doing the
opposite.
Of course we now live in a post-911 world, and I suppose we need to be
more open-minded about an asteroid crew dedicated to destroying
themselves along with a portion of the world. To that, I would say that
the irrational kinds of belief systems which result in such a death-wish
tend to produce incompetent individuals and societies. Major manned
space operations require very high levels of competency, both at the
individual and societal levels. The 911 hijackers succeeded by
redirecting Western aircraft which their native culture could never have
produced on its own.
And besides, I'm reasonably certain the real reason Sagan was against
moving asteroids was not the one he gave, but instead a dread that those
evil, oppressive old corporations might figure out a way to make a
profit off of other celestial bodies.
Regards,
Mike Combs
--- In spacesettlers@yahoogroups.com, "Combs, Mike"
>
> From: spacesettlers@yahoogroups.com
> [mailto:spacesettlers@yahoogroups.com] On Behalf Of Robert
>
> > the problem arises in the the object is spining and tumbling,
> > so that has to be stopped before you can begin to alter its
> > path, without breaking it up.
>
> Actually, it occurs to me that might be an advantage to the focused
> solar mirror approach. One could have a consistently vectored
thrust
> without first de-spinning the asteroid.
>
> Regards,
>
> Mike Combs
the mirror is floating free of the asteroid, but with the asteroid
changing its course on a constant basis, keeping the mirror focused
would not be easy. I'm afraid that would make it rather impractical.