China to target near-Earth object 2020 PN1 for asteroid deflection mission...

[Martin Brown]

On 29/10/2022 19:28, John Larkin wrote:

On 29 Oct 2022 17:50:57 GMT, Robert Latest <boblatest@yahoo.com
wrote:

Anthony William Sloman wrote:
John Larkin doesn\'t like thinking about what might be going on - it takes the
kind of effort he doesn\'t seem to want to put in.

As annoyingly uninformed as John Larkin usually is,

The topic here is electronic design. Show us some of yours.

I think he\'s right about
asteroid deflection tests. People have been doing the most amazing stellar
navigation maths for decades, one would think that a simple change in momentum
should be among the more predictable things.

They have already determined that they altered the targets trajectory.

No really dangerous, planet-killing asteroid is going to be deflected
usefully - or measurably - by a minor impact. It will take nukes to
apply enough momentum.

You have it almost exactly wrong. Nukes on asteroids are SciFi fantasy.

A tiny impulse given by a KE round soon enough would be enough to make
the difference between it hitting us square on and missing completely.

Even a few mm/s change in delta V makes a big difference to where and
when the asteroid\'s trajectory intersects ours. A miss is as good as a
mile (or +/-2000 miles in this case)

Even diverting it just enough to skip off the Earth\'s atmosphere instead
would be good enough to avert planet wide damage (although it would be
no fun being at ground zero underneath the track it took).

Modest ones are more likely there is a power law distribution of sizes
out there with small ones being most common. Rocks big enough to cause
sonic booms and hit the ground are more common than you might think:

https://www.amsmeteors.org/search/sonic+boom/?s=sonic+boom

Big impacts are not quite planet killing but they do reset the status
quo so that some other previously insignificant creatures get a turn.

That is pretty much how mammals inherited the world from dinosaurs. I
reckon the next turn will go insects - they have the most radiation
tolerant biochemistry of any living thing apart from tardigrades.

https://en.wikipedia.org/wiki/Tardigrade#Physiology

--
Regards,
Martin Brown

 

[Anthony William Sloman]

On Sunday, October 30, 2022 at 8:59:23 PM UTC+11, Martin Brown wrote:

On 29/10/2022 10:59, Anthony William Sloman wrote:
On Saturday, October 29, 2022 at 1:44:23 PM UTC+11, John Larkin
wrote:
On Fri, 28 Oct 2022 08:02:22 -0700 (PDT), Fred Bloggs
bloggs.fred...@gmail.com> wrote:

Watch out! There\'s no telling what these idiots will end up
doing. They could deflect the orbit enough for a later
collision.

https://spacenews.com/china-to-target-near-earth-object-2020-pn1-for-asteroid-deflection-mission/



Seems like a very expensive demonstration that F = M*A

There are lots of different objects in orbit around the solar system,
from lumps of rock to dirty snowballs.

A solid impactor hitting a dirty snowball would come out the other
side with most of its momentum intact. so it wouldn\'t apply a lot of
force or generate much acceleration.

At hypersonic speeds it will generate a powerful shockwave in the dirty
snowball which will almost certainly fragment it into component parts.
The same would apply if it was an ice bound conglomerate of rubble.

But it would probably remain a pile of rubble. It might get dispersed to some extent but if the bits weren\'t flying apart faster than the escape velocity of the pile of rubble, they\'d hang around in a clump, orbiting slowly around themselves and colliding with one another until the kinetic energy had been dissipated as heat.

You\'d want to know how much momentum would get transferred into the pile of rubble if you were interested in stopping it hitting the earth at some point in the predictable future.

> Might be a way to turn a former NEO into a new meteor stream.

Perhaps.

John Larkin doesn\'t like thinking about what might be going on - it
takes the kind of effort he doesn\'t seem to want to put in.

Doing the intercept autonomously is quite a challenge so they are using it to demonstrate their capabilities rather than anything else.

Getting there may be half the battle, but getting the momentum change you need has it\'s own challenges.

--
Bill Sloman, Sydney

 

[Mike Monett VE3BTI]

Martin Brown <\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

No really dangerous, planet-killing asteroid is going to be deflected
usefully - or measurably - by a minor impact. It will take nukes to
apply enough momentum.

You have it almost exactly wrong. Nukes on asteroids are SciFi fantasy.

Nukes not needed. Impact could break asteroid into many small pieces.

What is needed is 1,000 (or as many as required) rockets that land on the
asteroid. It will be rotating, so they have to be fired in the proper
sequence. The thrust in the right direction would deflect the orbit enough
to miss the Earth, and not place it on an impact path on subsequent orbits.

Musk\'s Mars rockets would do the job.

But they are unlikely to ever land on Mars. No point, as radiation would
kill everyone during the trip. Also, dust would cover solar arrays and
render them useless.

A Space Rock Smashed Into Mars\' Equator - and Revealed Chunks of Ice
Published 5:06 PM EDT, Thu October 27, 2022

Sadly, InSight\'s mission is running out of time. Increasing amounts
of dust have settled on the lander\'s solar panels, only exacerbated
by a continent-size dust storm detected on Mars in September, and
its power levels keep dropping.

The mission of NASA\'s robotic lander InSight \"is nearing an end as
dust obscures its solar panels,\" reports CNN. \"In a matter of weeks,
the lander won\'t be able to send a beep to show it\'s OK anymore.\"

The mission scientists estimate InSight will likely shut down in the
next six weeks, ending a promising mission to unlock the interior of
Mars.

https://www.cnn.com/2022/10/27/world/mars-nasa-meteoroid-impacts-
scn/index.html

InSight lander\'s final selfie on Mars shows why its mission is ending
Published 12:28 PM EDT, Wed May 25, 2022

https://www.cnn.com/2022/05/25/world/nasa-mars-insight-lander-final-selfie-
scn/index.html

----------------------------------------------------------------------
Thu Feb 10, 2022

Dr Paul Sutter breaks down how hard it is to get to Mars - and then
to live there.

Mars occasionally experiences global dust storms.

The dust on Mars has been blowing for billions of years, and it\'s
not like dust or sand you might find in a desert.

It\'s more like a fine talcum powder that gets everywhere and
occasionally coats the entire planet, blocking out the sun for
months on end.

Mars is also cold, really, really cold.

The average temperature on Mars is negative 81 degrees Fahrenheit,
and it gets as low as negative 220 degrees Fahrenheit.

And if that weren\'t enough, the soil on Mars is full of toxic
chemicals that have to be filtered out before you can use it as soil
to grow crops or to breathe in or to just exist in.

If we want to get from Earth to Mars, we have to do some very
complicated orbital dynamics.

We need to rely on Newton.

Isaac, Isaac? Okay, maybe he\'ll show up later.

Actually figuring out and plotting these missions is incredibly
difficult, and that\'s because the Earth in its orbit, it\'s
constantly moving, and so is Mars at a different distance and a
different speed.

So the most efficient way to get to Mars is to wait for
conjunctions, when our planets align.

To sketch out a mission here, let\'s say we\'re on the Earth and we
wanna send a mission to Mars.

But when we\'re in conjunction, by the time the mission actually gets
to Mars, it\'s not gonna be here, it\'s gonna be way up here.

So Mars is gonna be here in its orbit.

So our trajectory from Earth to Mars will look like this.

And with chemical rockets, that\'ll take about 180 days in a
weightless environment just to get to Mars.

Now, you get on Mars, you land, you poke around, you scare all the
Martians, you do your normal Martian business there, and you wanna
get back to Earth.

Well, guess what? You\'re not in conjunction anymore.

You have to wait.

You have to wait for the planets to align again.

So you have to wait on Mars as it continues its year before
everything lines up again.

And only then can you return to the Earth, and guess what? It\'s
another long trip.

When you launch from Mars here, the Earth is not gonna be in
conjunction anymore.

You have to travel another 180 days to intersect and safely return
to Earth.

This is one of the most energy-efficient missions to Mars, and the
entire mission duration is two years.

That\'s longer than any mission we have ever had in space before.

And that\'s just a single mission.

To build a colony of permanent human presence, we need tens,
hundreds, thousands of missions to the Red Planet.

We\'re gonna have to bring a lot of stuff.

I mean, oh boy, think about all the things that you surround
yourself with in your daily life.

Like air, we\'re gonna have to bring our own air to Mars or figure
out how to make it there.

We\'re gonna need communications gear so we can talk to each other
and call back to home.

We\'re gonna need a mode of transportation, not just to get to Mars,
but to move around on Mars, to explore.

We\'re gonna need storage, we need like grain silos.

Is there grain on Mars? No, there\'s not grain on Mars, but we\'re
gonna need silos for something eventually.

We need food, we\'re gonna have to either bring food from Earth or
figure out how to grow it on Martian soil.

We\'re gonna have to figure out how to extract resources from Mars.

We need to turn that Martian regolith into walls and ceilings and
toilets and stuff, all sorts of stuff.

We need utilities, we need plumbing and electrical conduits.

We need ethernet cables and cell phone transmitters.

We need fuel to power everything.

We need water, and yeah, there\'s plenty of water, but it\'s frozen,
so we need to heat it up first.

We need habitats, we need a place to live.

We need a room and a dining room and maybe even a foyer.

But we need all this stuff.

We\'ve begun to solve some of these challenges.

We\'ve started thinking about how to knock some of these items off
the list so that we can build up a permanent human presence.

And one very interesting idea relies on something called the
Sabatier process, named after a French chemist.

Did I say the Newton process? No, I didn\'t.

Isaac, you\'re late, you were supposed to be on the other side, thank
you.

What we\'re gonna talk later, okay? Anyway, the Sabatier process, let
me show you.

It\'s a very simple chemical reaction where if you take carbon
dioxide, which Mars has plenty of carbon dioxide, that\'s for sure,
and you add some hydrogen, which we can take along with us, it\'s a
relatively easy to transport fuel, put it under a lot of pressure at
some high temperatures, you get methane, which is a fuel, and as a
bonus, some water.

So one chemical reaction can transform something that\'s already
present on Mars into a source of fuel and water.

That\'s not so bad.

This doesn\'t solve all the problems, but it does start to chip away
at them.

Six months is a long time to get there, but that\'s doable.

It\'s not three years to a moon around Jupiter or something like
that, it\'s closer.

It\'s far from perfect, but you gotta start somewhere, and that\'s
probably the best place to start.

- This was a delight of a conversation.

I really appreciate your time.

- Thank you, Paul.

- That\'s all short-term visits.

For long-term habitation, we have to face a massive problem.

How do we turn this into this? This is a process called
terraforming, and it involves beefing up the Martian atmosphere.

But we need a lot of atmosphere.

We need at least 10 times the current Martian atmosphere for water
not to boil at body temperature.

And we need at least 20 times the pressure to make it pleasant to
walk around on the surface without a suit.

So we need to bulk up that atmosphere, what do we got? The best
things we have on Mars are the water and carbon dioxide locked up in
the soil and at the poles.

But unfortunately, there isn\'t enough, even if we liberated all of
it and put it all all into the atmosphere.

It would only raise the air pressure by like one or two or maybe
three times its current level, which isn\'t enough.

So we have to import an atmosphere from somewhere else.

We have to crash land comets from the outer solar system onto the
surface of Mars.

That kind of process is going to take generations, and we have to
fight an even bigger battle, because Mars doesn\'t have a magnetic
field.

The Earth\'s magnetic field protects the atmosphere from the
bombardment of solar radiation, so we have to introduce an
artificial magnetic field around Mars in order to keep that
atmosphere locked in.

For generations, Martian colonists are going to have to live
underground like some sort of Martian mole people.

Oh, and you got the note from my manager, right, that I\'m not
wearing the mole costume? Okay, got it.

That\'s long term.

Right now we\'re focused on stepping one foot on Mars and then 10 and
then a hundred, slowly building up to have a permanent human
presence.

There\'s no physics reason preventing us from inhabiting Mars, it\'s a
matter of technology and engineering and patience, and most
importantly, money.

But there\'s no reason why we can\'t eventually be on Mars. Humanity
will have a presence on Mars. Well, I\'m not going.

https://arstechnica.com/science/2022/02/mars-is-both-closer-and-farther-
away-than-it-seems-dr-paul-sutter-explains/



--
MRM

 

[John Larkin]

On Sun, 30 Oct 2022 00:14:32 -0700 (PDT), whit3rd <whit3rd@gmail.com>
wrote:

On Saturday, October 29, 2022 at 7:23:10 PM UTC-7, bill....@ieee.org wrote:
On Sunday, October 30, 2022 at 5:28:49 AM UTC+11, John Larkin wrote:


No really dangerous, planet-killing asteroid is going to be deflected usefully - or measurably - by a minor impact.

if you do it early enough, you could change a potential impact into an actual near miss. You can measure very small change in velocity quite accurately if you can point a laser at a corner-cube reflector. There are a couple up on the moon at the moment.

https://tmurphy.physics.ucsd.edu/apollo/lrrr.html
It will take nukes to apply enough momentum.

Nuclear blasts release energy. Persuading that energy to manifest itself as acceleration in a particular direction might be difficult.

Just ablate off about a cubic kilometer of dust or rock. That would be
trillions of times the momentum of a little impact or the flash of a
laser.

To get a good momentum boost, just aim a big laser pulse at the offender; ablation will occur,
and your reaction momentum comes from mass of the asteroid, not the delivery package (which,
from a safe distance away, can get in several shots).

Mere kilojoules.

The US, Russia, UK, China, and France have nukes. We could launch
dozens at a big asteroid. Have some redundancy.

 

[John Larkin]

On Sun, 30 Oct 2022 12:04:38 +0000, Martin Brown
<\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

On 29/10/2022 19:28, John Larkin wrote:
On 29 Oct 2022 17:50:57 GMT, Robert Latest <boblatest@yahoo.com
wrote:

Anthony William Sloman wrote:
John Larkin doesn\'t like thinking about what might be going on - it takes the
kind of effort he doesn\'t seem to want to put in.

As annoyingly uninformed as John Larkin usually is,

The topic here is electronic design. Show us some of yours.

I think he\'s right about
asteroid deflection tests. People have been doing the most amazing stellar
navigation maths for decades, one would think that a simple change in momentum
should be among the more predictable things.

They have already determined that they altered the targets trajectory.

That was tiny and could have been calculated. More expensive NASA
theatre.

No really dangerous, planet-killing asteroid is going to be deflected
usefully - or measurably - by a minor impact. It will take nukes to
apply enough momentum.

You have it almost exactly wrong. Nukes on asteroids are SciFi fantasy.

Words like that don\'t change the math.

A tiny impulse given by a KE round soon enough would be enough to make
the difference between it hitting us square on and missing completely.

Only if it is done far out in space and time. \"Soon enough\" indeed.

Even a few mm/s change in delta V makes a big difference to where and
when the asteroid\'s trajectory intersects ours. A miss is as good as a
mile (or +/-2000 miles in this case)

Do the math on that.

Even diverting it just enough to skip off the Earth\'s atmosphere instead
would be good enough to avert planet wide damage (although it would be
no fun being at ground zero underneath the track it took).

If it\'s small enough to bounce off the atmosphere it\'s no big threat.
And the atmosphere is a very thin skin on the planet; the geometry is
not promising.

 

[whit3rd]

On Sunday, October 30, 2022 at 8:24:53 AM UTC-7, John Larkin wrote:

On Sun, 30 Oct 2022 00:14:32 -0700 (PDT), whit3rd <whi...@gmail.com
wrote:
On Saturday, October 29, 2022 at 7:23:10 PM UTC-7, bill....@ieee.org wrote:
On Sunday, October 30, 2022 at 5:28:49 AM UTC+11, John Larkin wrote:


No really dangerous, planet-killing asteroid is going to be deflected usefully - or measurably - by a minor impact.

if you do it early enough, you could change a potential impact into an actual near miss. You can measure very small change in velocity quite accurately if you can point a laser at a corner-cube reflector. There are a couple up on the moon at the moment.

https://tmurphy.physics.ucsd.edu/apollo/lrrr.html
It will take nukes to apply enough momentum.

Nuclear blasts release energy. Persuading that energy to manifest itself as acceleration in a particular direction might be difficult.
Just ablate off about a cubic kilometer of dust or rock. That would be
trillions of times the momentum of a little impact or the flash of a
laser.

To get a good momentum boost, just aim a big laser pulse at the offender; ablation will occur,
and your reaction momentum comes from mass of the asteroid, not the delivery package (which,
from a safe distance away, can get in several shots).

Mere kilojoules.

Yeah, in a Shiva-class laser, forty-year old technology. But, it\'s not disturbing your nearby-orbiting
missile, because there\'s negligible momentum transfer to the laser, so you can recharge
and pulse the laser again. A few times per hour, for a few years, all off solar power.

In terms of how much mass you send UP, this would seem to be a good effective approach.

The US, Russia, UK, China, and France have nukes. We could launch
dozens at a big asteroid. Have some redundancy.

Yeah, that\'s one idea. It doesn\'t sound impossible, either. Economics, though, beats drama. Then
we look at the side effects. Your radioactive missile debris, it\'s going to be in an orbit similar
to the asteroid, i.e. Earth-intersecting?

 

[John Larkin]

On Sun, 30 Oct 2022 13:05:34 -0700 (PDT), whit3rd <whit3rd@gmail.com>
wrote:

On Sunday, October 30, 2022 at 8:24:53 AM UTC-7, John Larkin wrote:
On Sun, 30 Oct 2022 00:14:32 -0700 (PDT), whit3rd <whi...@gmail.com
wrote:
On Saturday, October 29, 2022 at 7:23:10 PM UTC-7, bill....@ieee.org wrote:
On Sunday, October 30, 2022 at 5:28:49 AM UTC+11, John Larkin wrote:


No really dangerous, planet-killing asteroid is going to be deflected usefully - or measurably - by a minor impact.

if you do it early enough, you could change a potential impact into an actual near miss. You can measure very small change in velocity quite accurately if you can point a laser at a corner-cube reflector. There are a couple up on the moon at the moment.

https://tmurphy.physics.ucsd.edu/apollo/lrrr.html
It will take nukes to apply enough momentum.

Nuclear blasts release energy. Persuading that energy to manifest itself as acceleration in a particular direction might be difficult.
Just ablate off about a cubic kilometer of dust or rock. That would be
trillions of times the momentum of a little impact or the flash of a
laser.

To get a good momentum boost, just aim a big laser pulse at the offender; ablation will occur,
and your reaction momentum comes from mass of the asteroid, not the delivery package (which,
from a safe distance away, can get in several shots).

Mere kilojoules.

Yeah, in a Shiva-class laser, forty-year old technology. But, it\'s not disturbing your nearby-orbiting
missile, because there\'s negligible momentum transfer to the laser, so you can recharge
and pulse the laser again. A few times per hour, for a few years, all off solar power.

We supplied three major systems to the NIF laser. It\'s a bunch of
enormous buildings. Nothing like that could ever be launched in
rockets, and it\'s only a couple of megajoules.

A megaton of h-bomb is about 4 petajoules.

In terms of how much mass you send UP, this would seem to be a good effective approach.

The US, Russia, UK, China, and France have nukes. We could launch
dozens at a big asteroid. Have some redundancy.

Yeah, that\'s one idea. It doesn\'t sound impossible, either. Economics, though, beats drama. Then
we look at the side effects. Your radioactive missile debris, it\'s going to be in an orbit similar
to the asteroid, i.e. Earth-intersecting?

Deflecting an asteroid with a dozen H-bombs would scatter fallout all
through space; not much would hit earth. And the total fallout
produced would be way less stuff than the 500+ atmospheric bomb tests
in the \'40s and \'50s.

 

[Joe Gwinn]

On Sun, 30 Oct 2022 14:16:37 -0700, John Larkin
<jlarkin@highlandSNIPMEtechnology.com> wrote:

On Sun, 30 Oct 2022 13:05:34 -0700 (PDT), whit3rd <whit3rd@gmail.com
wrote:

On Sunday, October 30, 2022 at 8:24:53 AM UTC-7, John Larkin wrote:
On Sun, 30 Oct 2022 00:14:32 -0700 (PDT), whit3rd <whi...@gmail.com
wrote:
On Saturday, October 29, 2022 at 7:23:10 PM UTC-7, bill....@ieee.org wrote:
On Sunday, October 30, 2022 at 5:28:49 AM UTC+11, John Larkin wrote:


No really dangerous, planet-killing asteroid is going to be deflected usefully - or measurably - by a minor impact.

if you do it early enough, you could change a potential impact into an actual near miss. You can measure very small change in velocity quite accurately if you can point a laser at a corner-cube reflector. There are a couple up on the moon at the moment.

https://tmurphy.physics.ucsd.edu/apollo/lrrr.html
It will take nukes to apply enough momentum.

Nuclear blasts release energy. Persuading that energy to manifest itself as acceleration in a particular direction might be difficult.
Just ablate off about a cubic kilometer of dust or rock. That would be
trillions of times the momentum of a little impact or the flash of a
laser.

To get a good momentum boost, just aim a big laser pulse at the offender; ablation will occur,
and your reaction momentum comes from mass of the asteroid, not the delivery package (which,
from a safe distance away, can get in several shots).

Mere kilojoules.

Yeah, in a Shiva-class laser, forty-year old technology. But, it\'s not disturbing your nearby-orbiting
missile, because there\'s negligible momentum transfer to the laser, so you can recharge
and pulse the laser again. A few times per hour, for a few years, all off solar power.

We supplied three major systems to the NIF laser. It\'s a bunch of
enormous buildings. Nothing like that could ever be launched in
rockets, and it\'s only a couple of megajoules.

A megaton of h-bomb is about 4 petajoules.


In terms of how much mass you send UP, this would seem to be a good effective approach.

The US, Russia, UK, China, and France have nukes. We could launch
dozens at a big asteroid. Have some redundancy.

Yeah, that\'s one idea. It doesn\'t sound impossible, either. Economics, though, beats drama. Then
we look at the side effects. Your radioactive missile debris, it\'s going to be in an orbit similar
to the asteroid, i.e. Earth-intersecting?

Deflecting an asteroid with a dozen H-bombs would scatter fallout all
through space; not much would hit earth. And the total fallout
produced would be way less stuff than the 500+ atmospheric bomb tests
in the \'40s and \'50s.

NASA did some thinking about such a propulsion approach:

..<https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion)>

There may be NIMBY objections.

Joe Gwinn

 

[whit3rd]

On Sunday, October 30, 2022 at 2:16:50 PM UTC-7, John Larkin wrote:

On Sun, 30 Oct 2022 13:05:34 -0700 (PDT), whit3rd <whi...@gmail.com
wrote:

On Sunday, October 30, 2022 at 8:24:53 AM UTC-7, John Larkin wrote:

The US, Russia, UK, China, and France have nukes. We could launch
dozens at a big asteroid. Have some redundancy.

Yeah, that\'s one idea. It doesn\'t sound impossible, either. Economics, though, beats drama. Then
we look at the side effects. Your radioactive missile debris, it\'s going to be in an orbit similar
to the asteroid, i.e. Earth-intersecting?

Deflecting an asteroid with a dozen H-bombs would scatter fallout all
through space; not much would hit earth. And the total fallout
produced would be way less stuff than the 500+ atmospheric bomb tests
in the \'40s and \'50s.

The minimal deflection solution, though, would splash lots of surface material into various paths,
mostly near the original path of the asteroid; that asteroid-surface stuff would be neutron
activated, a dirty atmosphere around the central rock. Earth might miss the rock, but lots
of the atmosphere will hit, and that\'ll be dominant over nuclear-device fragments.

Space nuclear explosions were tried, once; the persistence (in the VanAllen belt?) of the
generated isotopes was scary and it\'s banned by treaty nowadays.

 

[John Larkin]

On Sun, 30 Oct 2022 16:28:35 -0700 (PDT), whit3rd <whit3rd@gmail.com>
wrote:

On Sunday, October 30, 2022 at 2:16:50 PM UTC-7, John Larkin wrote:
On Sun, 30 Oct 2022 13:05:34 -0700 (PDT), whit3rd <whi...@gmail.com
wrote:

On Sunday, October 30, 2022 at 8:24:53 AM UTC-7, John Larkin wrote:

The US, Russia, UK, China, and France have nukes. We could launch
dozens at a big asteroid. Have some redundancy.

Yeah, that\'s one idea. It doesn\'t sound impossible, either. Economics, though, beats drama. Then
we look at the side effects. Your radioactive missile debris, it\'s going to be in an orbit similar
to the asteroid, i.e. Earth-intersecting?

Deflecting an asteroid with a dozen H-bombs would scatter fallout all
through space; not much would hit earth. And the total fallout
produced would be way less stuff than the 500+ atmospheric bomb tests
in the \'40s and \'50s.

The minimal deflection solution, though, would splash lots of surface material into various paths,
mostly near the original path of the asteroid; that asteroid-surface stuff would be neutron
activated, a dirty atmosphere around the central rock. Earth might miss the rock, but lots
of the atmosphere will hit, and that\'ll be dominant over nuclear-device fragments.

Space nuclear explosions were tried, once; the persistence (in the VanAllen belt?) of the
generated isotopes was scary and it\'s banned by treaty nowadays.

Well then, let the comet hit us.

 

[whit3rd]

On Sunday, October 30, 2022 at 6:21:01 PM UTC-7, John Larkin wrote:

On Sun, 30 Oct 2022 16:28:35 -0700 (PDT), whit3rd <whi...@gmail.com
wrote:

On Sunday, October 30, 2022 at 2:16:50 PM UTC-7, John Larkin wrote:
On Sun, 30 Oct 2022 13:05:34 -0700 (PDT), whit3rd <whi...@gmail.com
wrote:

On Sunday, October 30, 2022 at 8:24:53 AM UTC-7, John Larkin wrote:

The US, Russia, UK, China, and France have nukes. We could launch
dozens at a big asteroid. Have some redundancy.

The minimal deflection solution, though, would splash lots of surface material into various paths,
mostly near the original path of the asteroid; that asteroid-surface stuff would be neutron
activated, a dirty atmosphere around the central rock. Earth might miss the rock, but lots
of the atmosphere will hit, and that\'ll be dominant over nuclear-device fragments.

Space nuclear explosions were tried, once; the persistence (in the VanAllen belt?) of the
generated isotopes was scary and it\'s banned by treaty nowadays.

Well then, let the comet hit us.

Giving up when one idea has a problem? Out of ideas already, or just an habitual loser?

\"Let the comet hit us\" is a loser scenario, for sure.

 

[Anthony William Sloman]

On Monday, October 31, 2022 at 2:24:53 AM UTC+11, John Larkin wrote:

On Sun, 30 Oct 2022 00:14:32 -0700 (PDT), whit3rd <whi...@gmail.com
wrote:
On Saturday, October 29, 2022 at 7:23:10 PM UTC-7, bill....@ieee.org wrote:
On Sunday, October 30, 2022 at 5:28:49 AM UTC+11, John Larkin wrote:


No really dangerous, planet-killing asteroid is going to be deflected usefully - or measurably - by a minor impact.

if you do it early enough, you could change a potential impact into an actual near miss. You can measure very small change in velocity quite accurately if you can point a laser at a corner-cube reflector. There are a couple up on the moon at the moment.

https://tmurphy.physics.ucsd.edu/apollo/lrrr.html
It will take nukes to apply enough momentum.

Nuclear blasts release energy. Persuading that energy to manifest itself as acceleration in a particular direction might be difficult.

And how do you get the nuclear blast to do that?

https://history.nasa.gov/conghand/nuclear.htm

> Just ablate off about a cubic kilometer of dust or rock. That would be trillions of times the momentum of a little impact or the flash of a laser.

A nuclear blast in space generates a lot of high energy radiation.The space of any nearby rock will get very hot and evaporate off, but only the surface. High energy radiation won\'t get very far into the rock, so you won\'t evaporate off any cubic kilometer. The stuff you evaporate will get very hot so there will be some momentum transfer, but energy is mass times velocity squared, while momentum is mass times velocity, so you won\'t get a lot of momentum per joule of energy generated.

To get a good momentum boost, just aim a big laser pulse at the offender; ablation will occur, and your reaction momentum comes from mass of the asteroid, not the delivery package (which, from a safe distance away, can get in several shots).

Mere kilojoules.

But do it for long enough and it might do the trick.

> The US, Russia, UK, China, and France have nukes. We could launch dozens at a big asteroid. Have some redundancy.

Launching something that doesn\'t the asteroid\'s momentum by enough to matter would be a waste of time.

--
Bill Sloman, Sydney

 

[John Larkin]

On Sun, 30 Oct 2022 18:36:07 -0700 (PDT), whit3rd <whit3rd@gmail.com>
wrote:

On Sunday, October 30, 2022 at 6:21:01 PM UTC-7, John Larkin wrote:
On Sun, 30 Oct 2022 16:28:35 -0700 (PDT), whit3rd <whi...@gmail.com
wrote:

On Sunday, October 30, 2022 at 2:16:50 PM UTC-7, John Larkin wrote:
On Sun, 30 Oct 2022 13:05:34 -0700 (PDT), whit3rd <whi...@gmail.com
wrote:

On Sunday, October 30, 2022 at 8:24:53 AM UTC-7, John Larkin wrote:

The US, Russia, UK, China, and France have nukes. We could launch
dozens at a big asteroid. Have some redundancy.

The minimal deflection solution, though, would splash lots of surface material into various paths,
mostly near the original path of the asteroid; that asteroid-surface stuff would be neutron
activated, a dirty atmosphere around the central rock. Earth might miss the rock, but lots
of the atmosphere will hit, and that\'ll be dominant over nuclear-device fragments.

Space nuclear explosions were tried, once; the persistence (in the VanAllen belt?) of the
generated isotopes was scary and it\'s banned by treaty nowadays.

Well then, let the comet hit us.

Giving up when one idea has a problem? Out of ideas already, or just an habitual loser?

Willing to make engineering tradeoffs. A tiny bit of fallout to save
the planet.

\"Let the comet hit us\" is a loser scenario, for sure.

I was making fun of you.

 

[Anthony William Sloman]

On Monday, October 31, 2022 at 3:51:53 AM UTC+11, John Larkin wrote:

On Sun, 30 Oct 2022 12:04:38 +0000, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

On 29/10/2022 19:28, John Larkin wrote:
On 29 Oct 2022 17:50:57 GMT, Robert Latest <bobl...@yahoo.com> wrote:
Anthony William Sloman wrote:
John Larkin doesn\'t like thinking about what might be going on - it takes the
kind of effort he doesn\'t seem to want to put in.

As annoyingly uninformed as John Larkin usually is,

I think he\'s right about
asteroid deflection tests. People have been doing the most amazing stellar
navigation maths for decades, one would think that a simple change in momentum
should be among the more predictable things.

They have already determined that they altered the targets trajectory.

That was tiny and could have been calculated. More expensive NASA theatre.

It may have been tiny, but in order to calculate it they would have had to model the interaction between the impactor and the chunk of asteroid it hit.

You need to compare what actually happens with the predictions of your model before you can have much confidence in your model.

No really dangerous, planet-killing asteroid is going to be deflected usefully - or measurably - by a minor impact. It will take nukes to apply enough momentum.

You have it almost exactly wrong. Nukes on asteroids are SciFi fantasy.

Words like that don\'t change the math.

But John Larkin hasn\'t produced any math, and what he has posted suggests that he couldn\'t.

A tiny impulse given by a KE round soon enough would be enough to make
the difference between it hitting us square on and missing completely.

Only if it is done far out in space and time. \"Soon enough\" indeed.

That is the point.

Even a few mm/s change in delta V makes a big difference to where and when the asteroid\'s trajectory intersects ours. A miss is as good as a mile (or +/-2000 miles in this case)

Do the math on that.

Except that John Larkin clearly hasn\'t, and doesn\'t seem to know enough to have any idea how he might start doing that.

Even diverting it just enough to skip off the Earth\'s atmosphere instead would be good enough to avert planet wide damage (although it would be no fun being at ground zero underneath the track it took).

If it\'s small enough to bounce off the atmosphere it\'s no big threat.

Not that John Larkin has clue what he is talking about.

> And the atmosphere is a very thin skin on the planet; the geometry is not promising.

It\'s an unlikely event.

--
Bill Sloman, Sydney

 

[Anthony William Sloman]

On Monday, October 31, 2022 at 8:16:50 AM UTC+11, John Larkin wrote:

On Sun, 30 Oct 2022 13:05:34 -0700 (PDT), whit3rd <whi...@gmail.com>wrote:
On Sunday, October 30, 2022 at 8:24:53 AM UTC-7, John Larkin wrote:
On Sun, 30 Oct 2022 00:14:32 -0700 (PDT), whit3rd <whi...@gmail.com> wrote:
On Saturday, October 29, 2022 at 7:23:10 PM UTC-7, bill....@ieee.org wrote:
On Sunday, October 30, 2022 at 5:28:49 AM UTC+11, John Larkin wrote:

<snip>

No really dangerous, planet-killing asteroid is going to be deflected usefully - or measurably - by a minor impact.

if you do it early enough, you could change a potential impact into an actual near miss. You can measure very small change in velocity quite accurately if you can point a laser at a corner-cube reflector. There are a couple up on the moon at the moment.

https://tmurphy.physics.ucsd.edu/apollo/lrrr.html

It will take nukes to apply enough momentum.

Nuclear blasts release energy. Persuading that energy to manifest itself as acceleration in a particular direction might be difficult.

Just ablate off about a cubic kilometer of dust or rock. That would be trillions of times the momentum of a little impact or the flash of a laser.

Persuading a nuke to ablate off a whole cubic kilometer of dust or rock might be difficult. Hard X-rays don\'t go far into rock or dust. You might volatilise a thin layer (millimeter or less) and turn it into fast moving gas, but that won\'t be a lot of gas., or a lot of momentum.

To get a good momentum boost, just aim a big laser pulse at the offender; ablation will occur, and your reaction momentum comes from mass of the asteroid, not the delivery package (which, from a safe distance away, can get in several shots).

Mere kilojoules.

Yeah, in a Shiva-class laser, forty-year old technology. But, it\'s not disturbing your nearby-orbiting missile, because there\'s negligible momentum transfer to the laser, so you can recharge and pulse the laser again. A few times per hour, for a few years, all off solar power.

We supplied three major systems to the NIF laser. It\'s a bunch of enormous buildings. Nothing like that could ever be launched in rockets, and it\'s only a couple of megajoules.

But is is designed to produce very narrow pulses, all of which can be perfectly synchronised - or as perfectly synchronised as John Larkin\'s reworking of an old HP timing scheme can manage.

The kind of pulse that is narrow enough to volatilise the top layer of an asteroid is easier to make.

A megaton of h-bomb is about 4 petajoules.

In terms of how much mass you send UP, this would seem to be a good effective approach.

What you want is monentum, not energy. If the energy gets turned into a little bit of very fast moving gas evaporated off the surface, it won\'t generate a lot of momentum change per joule. Energy is mass times velocity squared. Momentum is mass times velocity. A lot of mass moving fairly slowly can deliver a lot more momentum change per joule than a fast-moving wisp of gas..

The US, Russia, UK, China, and France have nukes. We could launch dozens at a big asteroid. Have some redundancy.

Yeah, that\'s one idea. It doesn\'t sound impossible, either. Economics, though, beats drama. Then we look at the side effects. Your radioactive missile debris, it\'s going to be in an orbit similar to the asteroid, i.e. Earth-intersecting?

Deflecting an asteroid with a dozen H-bombs would scatter fallout all through space; not much would hit earth. And the total fallout produced would be way less stuff than the 500+ atmospheric bomb tests in the \'40s and \'50s.

If a dozen H-bombs could do the job, which seems unlikely.

--
Bill Sloman, Sydney

 

[Anthony William Sloman]

On Monday, October 31, 2022 at 12:59:01 PM UTC+11, John Larkin wrote:

On Sun, 30 Oct 2022 18:36:07 -0700 (PDT), whit3rd <whi...@gmail.com> wrote:
On Sunday, October 30, 2022 at 6:21:01 PM UTC-7, John Larkin wrote:
On Sun, 30 Oct 2022 16:28:35 -0700 (PDT), whit3rd <whi...@gmail.com> wrote:
On Sunday, October 30, 2022 at 2:16:50 PM UTC-7, John Larkin wrote:
On Sun, 30 Oct 2022 13:05:34 -0700 (PDT), whit3rd <whi...@gmail.com> wrote:
On Sunday, October 30, 2022 at 8:24:53 AM UTC-7, John Larkin wrote:

<snip>

Space nuclear explosions were tried, once; the persistence (in the VanAllen belt?) of the
generated isotopes was scary and it\'s banned by treaty nowadays.

Well then, let the comet hit us.

Giving up when one idea has a problem? Out of ideas already, or just an habitual loser?

Willing to make engineering tradeoffs. A tiny bit of fallout to save the planet.

The \"engineering\" involved in throwing nukes at an asteroid in the hope of deflecting it is entirely Hollywood visual effects - a Trumpean photo-opportunity.

Send hydrogen bobs to deflect and asteroid and build a border wall to discourage refugees. Great images. Unimpressive results.

\"Let the comet hit us\" is a loser scenario, for sure.

I was making fun of you.

Out of a comic excess of self-belief. It\'s hard to satirise John Larkin when he satirises himself so excessively.

--
Bill Sloman, Sydney

 

[none]

In article <a5df53e1-6687-472c-9cb5-6dce3ecb17d2n@googlegroups.com>,
Fred Bloggs <bloggs.fredbloggs.fred@gmail.com> wrote:

Watch out! There\'s no telling what these idiots will end up doing. They could deflect the orbit
enough for a later collision.

https://spacenews.com/china-to-target-near-earth-object-2020-pn1-for-asteroid-deflection-mission/

The Chinese scientists work for the benefit of humanity to ward off disasters.
Or do you think they plan to deflects an asteroid to target the USA?

Probably it is probably not correct to label rocket scientists as idiots.

Groetjes Albert
--
\"in our communism country Viet Nam, people are forced to be
alive and in the western country like US, people are free to
die from Covid 19 lol\" duc ha
albert@spe&ar&c.xs4all.nl &=n http://home.hccnet.nl/a.w.m.van.der.horst

 

[John Larkin]

On Tue, 01 Nov 2022 13:23:09 +0100, albert@cherry.(none) (albert)
wrote:

In article <a5df53e1-6687-472c-9cb5-6dce3ecb17d2n@googlegroups.com>,
Fred Bloggs <bloggs.fredbloggs.fred@gmail.com> wrote:
Watch out! There\'s no telling what these idiots will end up doing. They could deflect the orbit
enough for a later collision.

https://spacenews.com/china-to-target-near-earth-object-2020-pn1-for-asteroid-deflection-mission/

The Chinese scientists work for the benefit of humanity to ward off disasters.

No, they work for the power and glory of the Party. They don\'t dare do
anything else.

 

[Jeroen Belleman]

On 2022-11-01 14:01, John Larkin wrote:

On Tue, 01 Nov 2022 13:23:09 +0100, albert@cherry.(none) (albert)
wrote:

In article <a5df53e1-6687-472c-9cb5-6dce3ecb17d2n@googlegroups.com>,
Fred Bloggs <bloggs.fredbloggs.fred@gmail.com> wrote:
Watch out! There\'s no telling what these idiots will end up doing. They could deflect the orbit
enough for a later collision.

https://spacenews.com/china-to-target-near-earth-object-2020-pn1-for-asteroid-deflection-mission/

The Chinese scientists work for the benefit of humanity to ward off disasters.

No, they work for the power and glory of the Party. They don\'t dare do
anything else.

It\'s also a demonstration of how well they can target random objects
floating around in space. That\'s of obvious strategic value: \"We can
hit your spy and navigation satellites at any moment\".

Jeroen Belleman

 

[Anthony William Sloman]

On Wednesday, November 2, 2022 at 12:01:43 AM UTC+11, John Larkin wrote:

On Tue, 01 Nov 2022 13:23:09 +0100, albert@cherry.(none) (albert)
wrote:
In article <a5df53e1-6687-472c...@googlegroups.com>,
Fred Bloggs <bloggs.fred...@gmail.com> wrote:
Watch out! There\'s no telling what these idiots will end up doing. They could deflect the orbit
enough for a later collision.

https://spacenews.com/china-to-target-near-earth-object-2020-pn1-for-asteroid-deflection-mission/

The Chinese scientists work for the benefit of humanity to ward off disasters.

No, they work for the power and glory of the Party. They don\'t dare do anything else.

In the same why that John Larkin works to glorify Donald Trump?

In reality the the people getting the individual bits of particular system to do their job inside the gear that ends up getting sent into space to deflect a specific asteroid will have much the same motivations as team members everywhere - mainly keeping their bosses happy enough that they will keep on getting paid.

The glory of the party and the benefit of humanity are both essentially empty phrases used by politicians when they are putting together press releases.

--
Bill Sloman, Sydney