Author Topic: Deflecting or destroying dangerous asteroids  (Read 59640 times)

Offline Hog

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Re: Deflecting or destroying dangerous asteroids
« Reply #100 on: 08/05/2017 09:49 am »
There have been nuclear weapons tests in space.
Yes, the largest was a W-49 1,400,000 tonnes of equivalent yield of TNT at an altitude of 400kms. Electrons from the blast were detectable for 5 years afterwards.  The Starfish Prime detonation was the best instrumented of the USA tests.
There were concerns for orbiting American astronauts.

Yucca 28 April 1958, 1.7 kt, 26.2 km
Teak, 1 August 1958, 3.8 Mt, 76.8 km
Orange, 12 August 1958, 3.8 Mt, 43 km

United States USA – Argus – South Atlantic Ocean
Argus I, 27 August 1958, 1.7 kt, 200 km
Argus II, 30 August 1958, 1.7 kt, 240 km
Argus III, 6 September 1958, 1.7 kt, 540 km (The highest known man made nuclear explosion)

USA – Dominic I – (Operation Fishbowl) – Johnston Atoll, Pacific Ocean
Bluegill, 3 June 1962, failed
Bluegill Prime, 25 July 1962, failed
Bluegill Double Prime, 15 October 1962, failed
Bluegill Triple Prime, 26 October 1962, 410 kt, 50 km
Starfish, 20 June 1962, failed
Starfish Prime, 9 July 1962, 1.4 Mt, 400 km (The largest man made nuclear explosion in outer space)
Checkmate, 20 October 1962, 7 kt, 147 km
Kingfish, 1 November 1962, 410 kt, 97 km

USSR – 1961 tests – Kapustin Yar
Test #88, 6 September 1961, 10.5 kt, 22.7 km
Test #115, 6 October 1961, 40 kt, 41.3 km
Test #127, 27 October 1961, 1.2 kt, 150 km
Test #128, 27 October 1961, 1.2. kt, 300 km

USSR – Soviet Project K nuclear tests – Kapustin Yar
Test #184, 22 October 1962, 300 kt, 290 km
Test #187, 28 October 1962, 300 kt, 150 km
Test #195, 1 November 1962, 300 kt, 59 km

"The worst effects of a Soviet high-altitude test occurred on 22 October 1962, in the Soviet Project K nuclear tests (ABM System A proof tests) when a 300 kt missile-warhead detonated near Dzhezkazgan at 290-km altitude. The EMP fused 570 km of overhead telephone line with a measured current of 2,500 A, started a fire that burned down the Karaganda power plant, and shut down 1,000-km of shallow-buried power cables between Aqmola and Almaty."

What I find hugely surprising is the amount of actual high altitude nuclear tests that occurred during the Cuban Missile Crisis. 4 Soviet and 2 American.  That's a LOT of missile and nuclear activity occurring when Strategic Air Command is at DEFCON-2 and the rest of the USA contiguous forces are at DEFCON-3. SAC remained at DEFCON-2 until November 15,1962. The only other time DEFCON-2 was ordered was during Desert Storm for Gulf War#1. The Sept 11 2001 attacks caused Donald Rumsfeld the Sec of Def to raise the Defense Condition to DEFCON-3 and to prepare for a possible increase to DEFCON-2.

 

Readiness condition     Exercise term        Description                   Readiness
DEFCON 1 COCKED PISTOL    Nuclear war is imminent                Maximum readiness
DEFCON 2 FAST PACE Next step to nuclear war Armed Forces ready to deploy and engage in less than 6 hours
DEFCON 3 ROUND HOUSE Increase in force readiness above that required for normal readiness Air Force ready to mobilize in 15 minutes
DEFCON 4 DOUBLE TAKE Increased intelligence watch and strengthened security measures  Above normal readiness
DEFCON 5 FADE OUT                Lowest state of readiness               Normal readiness


I wonder if there would be any sort of DEFCON adjustment for an imminent meteorite hit?

I would think that detonating a warhead at an altitude of 400km would be very different than the distance from Earth that would be required to affect to course of the meteor, or to deflect it from a collision with Earth?  I would think, the greater the range, the better.


Pic #1 Starfish Prime The debris fireball stretching along Earth's magnetic field with air-glow aurora as seen at 3 minutes from a surveillance aircraft.

Pic#2 The flash created by the explosion as seen through heavy cloud cover from Honolulu 1,445 km away




« Last Edit: 08/05/2017 09:50 am by Hog »
Paul

Online meberbs

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Re: Deflecting or destroying dangerous asteroids
« Reply #101 on: 08/05/2017 02:30 pm »
I just want to note that the chart that Propylox posted above is dated "2015", but in my attempts to find an updated version, I discovered that it appears the data in that chart was actually from 2014.

The National Near Earth Object Prepardness strategy from December 2016 uses what appears to be the same data. Unfortunately this makes me think there isn't an updated chart available.

It did lead me to what appears to be the original data source. This presentation is from March, 2014. I find the specific date signficant, because since then, we have been discovering asteroids at a rate of over 1000 per year.

I also attached a slide from the original source which is interesting because it shows the projected completion curve for once the 90% of > 140 m goal is met.

I estimate about 40% completion at that point for > 60 m. The authors estimate about 1/3 of Tunguska size and 10% of ones large enough to make it to the ground (>25 m) at that point.

also of note:
Quote
Current surveys have almost a 50% chance of detecting a “death plunge” small object with enough time for civil defense measures; future surveys have the potential to do even better with appropriate observing protocol.

I'd really like to see updated current data, but the original study makes it pretty clear you can't just add in the new detections, you also should make use of the additional data to refine the population size estimates.
« Last Edit: 08/05/2017 02:34 pm by meberbs »

Offline hop

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Re: Deflecting or destroying dangerous asteroids
« Reply #102 on: 08/05/2017 07:16 pm »
In a decade, if everything planned works out, we might be able to see half the objects the size of Asteroid 2017 001, which was only discovered three days after it skimmed Earth, and 10% of the objects similar to the Chelyabinsk air-blast (which could have easily leveled counties or impacted the ground).
This is incorrect.  Chelyabinsk size objects have no potential to "level counties", and if it had survived to the ground (edit: unlikely for bodies of this size), it would have had the effect of a medium sized nuke and made a small crater. Bad day if it happens in your neighborhood, but not a regional or global catastrophe.

When you calculate the risk of small objects like this, you have to include the probability it will hit something of value. 70% of the Earth's surface is ocean (and things in this size range are far too small to create a tsunami risk) and only a tiny fraction is densely populated.

Again, see http://impact.ese.ic.ac.uk/ImpactEffects/ for a rough idea of what the effects are.
Quote
Why even bother financing such a program if it's to be so completely ineffective, especially with volunteer options like ATLAS doing just as much?
ATLAS gets NASA funding (http://www.fallingstar.com/nasa_funding.php) and only addresses a narrow section of the overall risk.

Why bother? Detecting 90% of the >140m accounts for a huge fraction of the overall risk.

Quote
If it's to be a funded project we should build 10m-70m telescopes, whatever is necessary (size is neither cost nor payload confined as a Hubble/WFIRST-type mission could support over a 110m telescope), to actually do the job while also cataloguing pretty much the entire asteroid belt, solar system, it's moons and much of the Kuiper Belt.
I'm having trouble parsing this, but if you can build a >10m space telescope for the cost of NEOCam, you should probably submit a proposal to NASA. Good luck...
« Last Edit: 08/05/2017 11:17 pm by hop »

Offline hop

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Re: Deflecting or destroying dangerous asteroids
« Reply #103 on: 08/05/2017 07:37 pm »
I'd really like to see updated current data, but the original study makes it pretty clear you can't just add in the new detections, you also should make use of the additional data to refine the population size estimates.
The DECam paper I linked earlier (https://arxiv.org/abs/1707.04066) has recent estimates of the size distribution, with comparison to previous work. Figure 8 attached.



« Last Edit: 08/05/2017 07:38 pm by hop »

Offline Propylox

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Re: Deflecting or destroying dangerous asteroids
« Reply #104 on: 08/05/2017 09:05 pm »
... if you can build a >10m space telescope for the cost of NEOCam, you should probably submit a proposal to NASA.
NEOCam is planning a 0.5m primary, which if reground as a secondary would suggest a primary collecting diameter around 7m and associated 25% increase in launch mass. But why would I submit such a proposal to NASA considering the poor state of their current programs (SLS, ISS, Commercial), their planned ones (DSG and..?) and their dysfunctional administrative system (program management, selection, budgeting, etc).
If they got better, better options like this and others will both become available and be selected. For now NASA's still better than ESA, but still not worth the time nor effort or expectations.
« Last Edit: 08/05/2017 09:11 pm by Propylox »

Offline as58

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Re: Deflecting or destroying dangerous asteroids
« Reply #105 on: 08/05/2017 09:14 pm »
... if you can build a >10m space telescope for the cost of NEOCam, you should probably submit a proposal to NASA.
NEOCam is planning a 0.5m primary, which if reground as a secondary would suggest a primary collecting diameter around 7m and associated 25% increase in launch mass. But why would I submit such a proposal to NASA considering the state of their current programs (SLS, ISS, Commercial), their planned ones (DSG and..?) and their dysfunctional administrative system (program management, selection, budgeting, etc)? If they got better, better options like this and others will both become available and be selected. For now it's still better than ESA, but still not worth the time nor high expectations.

Could you please describe how this telescope design that you keep alluding to would work?

Offline RonM

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Re: Deflecting or destroying dangerous asteroids
« Reply #106 on: 08/05/2017 09:20 pm »
NEOCam is planning a 0.5m primary, which if reground as a secondary would suggest a primary collecting diameter around 7m and associated 25% increase in launch mass.

No, that's not how it works. A 7m mirror would have nearly 200 times the surface area of a 0.5m mirror. How could you possibly build a 7m telescope that only masses 25% more than a 0.5m? Hubble "only" has a 2.4m mirror.

We don't need large space telescopes to find asteroids. Multiple NEOCam missions would be nice to speed up the survey.

Please do some research before you post.

Offline hop

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Re: Deflecting or destroying dangerous asteroids
« Reply #107 on: 08/05/2017 09:45 pm »
Could you please describe how this telescope design that you keep alluding to would work?
Seconded, but in it's own thread, please!

Offline Jim

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Re: Deflecting or destroying dangerous asteroids
« Reply #108 on: 08/05/2017 09:54 pm »
[. But why would I submit such a proposal to NASA considering the poor state of their current programs (SLS, ISS, Commercial), their planned ones (DSG and..?) and their dysfunctional administrative system (program management, selection, budgeting, etc).
If they got better, better options like this and others will both become available and be selected. For now NASA's still better than ESA, but still not worth the time nor effort or expectations.

Wrong on all counts.  All unsupported opinion.
There is no "poor state" of the science programs.  It is healthy.

"dysfunctional administrative system"? You really don't know what you are talking about.  The proposers run most of the missions.

NASA is the only show around.  ESA doesn't even come close and has worse "problems".


Offline hop

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Re: Deflecting or destroying dangerous asteroids
« Reply #109 on: 08/05/2017 10:22 pm »
NEOCam is planning a 0.5m primary, which if reground as a secondary would suggest a primary collecting diameter around 7m and associated 25% increase in launch mass. But why would I submit such a proposal to NASA considering
If you can't propose it yourself, there's a whole lot of people in the field who would love to be able to propose a 7m telescope on a Discovery budget! Or better yet, a 2m telescope on an even smaller budget.

NEOCam was proposed for Discovery, which is a competitive, PI-lead, cost capped program. That means the PI proposes the mission, NASA and outside experts evaluate the technical credibility and science value, and if it's selected, NASA pays for it. NEOCam wasn't selected in the last round, but it did get additional development funding. An otherwise equivalent, much larger telescope for similar cost would be very competitive indeed.

Furthermore, the community is currently studying concepts Hubble follow-on visible / near IR  / UV telescope in the 8-16 meter class (ATLAST / HDST / LUVOIR etc.) This is expected to be flagship cost (i.e. several to many billions) mission. If it could be done on a Discovery budget (~0.5 billion) that would be a game changer for the entire field.

(but again, if you want to discuss how you think this can be done, it really deserves it's own thread)
« Last Edit: 08/05/2017 11:15 pm by hop »

Online gongora

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Re: Deflecting or destroying dangerous asteroids
« Reply #110 on: 08/06/2017 01:17 am »
... Hubble "only" has a 2.4m mirror.
Sorry, ft to m SNAFU. 43ft ~ 6.5m for Kepler , 110ft ~ 33.6m for WFIRST , 294ft ~ 91m for JWST

Point being very large telescopes aren't the financial and technical hurdle so many assume. And if such telescopes were available, they'd be requested for missions such as asteroid detection. Which is in itself proof that the current proposals aren't based on mission demands, but the low bar of beggars. So I ask what's the point of a project that will take forever, be incomplete when "finished" while not addressing the most likely source of impacts and only one we can stop: small meteors - especially when good options are available?
If you're going to do something, do it right. Don't offer snails, call it gourmet and demand hundreds of $millions.

...ESA doesn't even come close and has worse "problems".
On that, we're in complete agreement. I'd add it's not just their space program, but entire scientific endeavours.

What the hell are you talking about?  What are those numbers in your post supposed to mean, and why do you think it's trivial to build space telescopes an order of magnitude larger than anything that's been flown?

Offline gospacex

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Re: Deflecting or destroying dangerous asteroids
« Reply #111 on: 08/06/2017 08:49 am »
NEOCam is planning a 0.5m primary, which if reground as a secondary would suggest a primary collecting diameter around 7m and associated 25% increase in launch mass.

No, that's not how it works. A 7m mirror would have nearly 200 times the surface area of a 0.5m mirror. How could you possibly build a 7m telescope that only masses 25% more than a 0.5m? Hubble "only" has a 2.4m mirror.

We don't need large space telescopes to find asteroids. Multiple NEOCam missions would be nice to speed up the survey.

Please do some research before you post.

It's some 5th time you and others said this to him. He will not.

Offline whitelancer64

Re: Deflecting or destroying dangerous asteroids
« Reply #112 on: 08/07/2017 02:55 pm »
This is the Dunning–Kruger effect, he obviously thinks he knows what he's talking about, but he doesn't actually know enough about these topics to know that he's wrong.
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Offline Lar

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Re: Deflecting or destroying dangerous asteroids
« Reply #113 on: 08/07/2017 08:42 pm »
Let's not psychoanalyze each other, k? Some posts ought to be edited or deleted.
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Online meberbs

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Re: Deflecting or destroying dangerous asteroids
« Reply #114 on: 08/09/2017 12:44 am »
One of the points I have been trying make lately is that it takes a space telescope to really ascertain asteroid threats.  JWST is so late and overcost ($10B+ and climbing) it really makes you wonder about the impact Will be if it fails.

There is no way the telescope of JWST is 91m. More like 6.5m.

Does JWST have specific goals to monitor asteroids or inbound comets that are Earth grazing?  I always (or 17 years ago) got the impression it was to be used for deep sky surveys using a variety of IR cameras/sensors.  Are there dedicated space telescopes for asteroids flying now???
JWST is really irrelevant to the thread. While it is capable of observations inside the solar system, it is really not designed for searching for NEOs, and in most cases is incapable of pointing in a way to see them. It could be used for some IR characterization of comets or certain NEOs, but even without the pointing restrictions, it would be a terrible choice for a survey to discover new objects. It is intended for long dwells at objects within a narrow field of view. Details about the intra-solar system capabilities are at the link below.

https://jwst.nasa.gov/faq_solarsystem.html

As for space based telescopes, there was the NEOWISE mission, and NEOCAM is in the planning stages. JWST is a gigantic, complicated telescope mostly for looking far away. JWST is just not a relevant baseline (cost, schedule, or complexity) for discussing space based telescopes for NEO asteroid searches.

P.S. you are right about the size of JWST, but seem to have misstated the cost, $10 billion is the current estimate of the final bill including international contributions and operation, and this number hasn't really changed since the last re-plan years ago. It is not the amount that has been spent so far, and it is not climbing.

Offline Nomadd

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Re: Deflecting or destroying dangerous asteroids
« Reply #115 on: 08/09/2017 12:56 am »
Let's not psychoanalyze each other, k?
Why do you think you feel that way?
Those who danced were thought to be quite insane by those who couldn't hear the music.

Re: Deflecting or destroying dangerous asteroids
« Reply #116 on: 08/21/2017 09:20 am »
What if you combined the nuke and the impactor mission?

And for this proposal, you have to understand i'm a complete newb at this :)

If we know well in advance that a large stone has our name on it. Im counting on red tape going out the window. So does economical issues.

Do the proposed impactor mission at high initial speed. On top of the impactor we put a smaller version of the proposed Orion damper with a large nuke behind it. The impactor now has a high delta-V. Just Before impact, we detonate the nuke and give the impactor at huge boost in speed. Plus any energy the nuke itself Projects around the plate.

Offline hop

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Re: Deflecting or destroying dangerous asteroids
« Reply #117 on: 08/21/2017 05:40 pm »
On top of the impactor we put a smaller version of the proposed Orion damper with a large nuke behind it. The impactor now has a high delta-V. Just Before impact, we detonate the nuke and give the impactor at huge boost in speed. Plus any energy the nuke itself Projects around the plate.
What do you gain by transferring energy from the nuke, to the impactor and then to the target? Why not cut out the middle man?

In general, nukes have the highest energy density, so launching a combination of nukes + kinetic impactors gives you less capability than using the same mass of nukes alone. Kinetic impactors are technically and politically simpler, so they are attractive in cases where they provide sufficient energy in a reasonable launch mass.
« Last Edit: 08/21/2017 05:40 pm by hop »

Offline bradjensen3

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Re: Deflecting or destroying dangerous asteroids
« Reply #118 on: 08/21/2017 10:58 pm »
Assuming for the moment that the hypothesis that Ceres has a layer of ice under its surface, and ice volcanoes that lead to the surface, put a water NTR on the asteroid, then send it automated rockets full of water from Ceres for months or years to refill the NTR's reaction mass.

If there is no large amount of water on Ceres, please forget this suggestion was ever made.

If you know the path of the asteroid years in advance, you do not have to deflect it to the side. Any increase or decrease in its velocity is going to change the orbit enough that it won't show up at the appointed time.

Re: Deflecting or destroying dangerous asteroids
« Reply #119 on: 08/22/2017 08:25 am »
On top of the impactor we put a smaller version of the proposed Orion damper with a large nuke behind it. The impactor now has a high delta-V. Just Before impact, we detonate the nuke and give the impactor at huge boost in speed. Plus any energy the nuke itself Projects around the plate.
What do you gain by transferring energy from the nuke, to the impactor and then to the target? Why not cut out the middle man?

In general, nukes have the highest energy density, so launching a combination of nukes + kinetic impactors gives you less capability than using the same mass of nukes alone. Kinetic impactors are technically and politically simpler, so they are attractive in cases where they provide sufficient energy in a reasonable launch mass.

Yes, really should have thought about that. How ever I read only 40% of the nukes energy is radiation and what not. If we put a gas between the impactor and the nuke. Could we also harwest the pressure wave in som manner and get more energy out of it?

 

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