Chinese propose method for deflecting asteroid Apophis

Aug 22, 2011 by Bob Yirka report
Orientation of the sail cone and clock angles. Image: arXiv:1108.3183v1 [astro-ph.IM]

(PhysOrg.com) -- Chinese scientist Shengping Gong and associates at Tsinghua University in Beijin have proposed an alternative method of deflecting the asteroid Apophis to ensure that it does not strike the earth. They believe that rather than just blowing it up ala the European Space Agency’s Don Quijote project, a better approach would be to use a solar sail, as described in their paper on the preprint server arXiv, to slowly nudge the asteroid off its trajectory just enough to keep it from bothering us here on Earth.

Apophis is approximately 880 feet in diameter and weighs an estimated 46 million tons. If it were to strike the earth, it would most certainly cause damage for thousands of miles around the epicenter, but wouldn’t spell doom for the planet as a whole.

First discovered in 2004 by Roy Tucker, David Tholen and Fabrizio Bernardi at the Kitt Peak National Observatory, Apophis was after initial study, thought to have a possibility of hitting the ; then after further study, it appeared that an impact was unlikely. Then later it was noted that when Apophis makes a close approach in 2029, there is a possibility that it could pass through what is known as a “keyhole” (a small gravitational zone near enough a planet to alter the course of an object) near our planet that could cause the next pass, in 2036, to hit us. Because of the dizzying number of variables involved in such a scenario, however, there appears to be differing views as to the probability of that actually happening. There also seems to be some disagreement as to the origin of its name; some suggest that Apophis comes from the ancient Egyptian deity, enemy of the uncreator Ra, Apep. Others suggest it’s simply a nod to the character Apophis on the television show Stargate SG-1.

In either case, Gong et al, propose using a space vehicle propelled by a solar sail that would move in a retrograde (opposite) orbit relative to Apophis fast enough so that when the collision occurred (like two cars running head on into each other on a freeway) the vessel would strike the asteroid moving at a relative speed of some 55 miles per second, enough they say, to push the offending off its current path.

The problem is, as the Chinese group readily admit, is in being precise enough in aiming the vessel. With all the variables at play (including the years it would have to travel) it would seem an almost impossible task. Nonetheless, the team seems undaunted, suggesting that such a vehicle could be built and launched in the time frame available.

Explore further: Lockheed Martin successfully mates NOAA GOES-R satellite modules

More information: Utilization of H-reversal Trajectory of Solar Sail for Asteroid Deflection, Shengping Gong, Junfeng Li, Xiangyuan Zeng, arXiv:1108.3183v1 [astro-ph.IM] arxiv.org/abs/1108.3183

Abstract
Near Earth Asteroids have a possibility of impacting with the Earth and always have a thread on the Earth. This paper proposes a way of changing the trajectory of the asteroid to avoid the impaction. Solar sail evolving in a H-reversal trajectory is utilized for asteroid deflection. Firstly, the dynamics of solar sail and the characteristics of the H-reversal trajectory are analyzed. Then, the attitude of the solar sail is optimized to guide the sail to impact with the object asteroid along a H-reversal trajectory. The impact velocity depends on two important parameters: the minimum solar distance along the trajectory and lightness number. A larger lightness number and a smaller solar distance lead to a higher impact velocity. Finally, the deflection capability of a solar sail impacting with the asteroid along the H-reversal is discussed. The results show that a 10 kg solar sail with a lead-time of one year can move Apophis out of a 600-m keyhole area in 2029 to eliminate the possibility of its resonant return in 2036.

Via ArXiv blog

Related Stories

NASA Statement on Student Asteroid Calculations

Apr 17, 2008

The Near-Earth Object Program Office at NASA's Jet Propulsion Laboratory in Pasadena, Calif., has not changed its current estimates for the very low probability (1 in 45,000) of an Earth impact by the asteroid ...

Astronomers continue to monitor asteroid Apophis

Mar 11, 2011

Asteroid Apophis continues to be an object of interest for astronomers. Even though the possibility of an Earth impact by the now-famous asteroid has been ruled out during its upcoming close encounter on April ...

NASA Refines Asteroid Apophis' Path Toward Earth

Oct 07, 2009

(PhysOrg.com) -- Using updated information, NASA scientists have recalculated the path of a large asteroid. The refined path indicates a significantly reduced likelihood of a hazardous encounter with Earth ...

Shining light on asteroid deflection

Feb 02, 2011

(PhysOrg.com) -- So you think global warming is a big problem? What could happen if a 25-million-ton chunk of rock slammed into Earth? When something similar happened 65 million years ago, the dinosaurs and ...

Recommended for you

Winter in the southern uplands of Mars

17 hours ago

Over billions of years, the southern uplands of Mars have been pockmarked by numerous impact features, which are often so closely packed that they overlap. One such feature is Hooke crater, shown in this ...

Five facts about NASA's ISS-RapidScat

17 hours ago

NASA's ISS-RapidScat mission will observe ocean wind speed and direction over most of the globe, bringing a new eye on tropical storms, hurricanes and typhoons. Here are five fast facts about the mission.

User comments : 84

Adjust slider to filter visible comments by rank

Display comments: newest first

Pyle
1 / 5 (6) Aug 22, 2011
I think somebody in a comment section here recommended using a solar sail to adjust the trajectory of an asteroid. Something tells me it didn't go quite like Gong et al are suggesting.

btw, why are we going to carefully ram an asteroid when an explosive charge achieves a more certain outcome?
Recovering_Human
3.2 / 5 (10) Aug 22, 2011
Yeah, like the ESA and NASA hadn't already considered this as an option. Leave it to the pros, please.
BenjaminButton
1.8 / 5 (5) Aug 22, 2011
A gravity tractor like that discussed and already several years in development is still a much better idea! They're trying quite hard to appear to know what they're talking about here me thinks!
Dichotomy
4 / 5 (4) Aug 22, 2011
Hey if they want to spend their money working on it more power to them. If it fails we'll just blow that up too!:)
GSwift7
1.5 / 5 (4) Aug 22, 2011
Approaching it from behind will give a much more likely chance to intercept it. Once you do that, there are lots of options. Catching it on its way back out to space would be best, since it won't be outgassing as much, and would be much safer to approach and easier to work with. Of course, whatever you do, it would be hard to be sure that you changed to trajectory enough until it actually comes back for another pass.

I wonder if simply blasting off a clean spot on one side might be enough. If you open up a fresh patch on one side of the surface, then the sun should do the rest, as it passes through parihelion. The fresh spot should outgas much more than the dirty old suface elsewhere.
Kontrast
4.9 / 5 (8) Aug 22, 2011
Regardless of what exactly they end up doing, I have to applaud the different space agencies that they intend to use Apophis as a test object to prepare for a more serious scenario.

It not only shows some foresight but it doesn't even matter whether it works or not, it will still lead to a lot of advances and further our knowledge.
SteveL
3.7 / 5 (3) Aug 22, 2011
They have done the calculations and claim it's not going to hit us. If this is the case then let's just leave it alone. Seems every time we mess with something we screw something else up. On the other hand, if there is a real chance it will hit us (perhaps due to changes in solar output?) then we should take steps to protect ourselves. Just because we can isn't always the best reason to mess with something. I'd rather see the billions spent on projects that would advance space exploration and utilizing resources from space.
Doug_Huffman
2.3 / 5 (6) Aug 22, 2011
If this is the case then let's just leave it alone. Seems every time we mess with something we screw something else up. ... Just because we can isn't always the best reason to mess with something.
Called the precautionary principle and advanced by the 1930 Germans as Vorsorgeprinzip and more recently by The World Charter for Nature, which was adopted by the UN General Assembly in 1982.
Kontrast
3.8 / 5 (5) Aug 22, 2011
They have done the calculations and claim it's not going to hit us. If this is the case then let's just leave it alone. Seems every time we mess with something we screw something else up.


For example? What did we mess up?

Seriously, do you really want to wait until we find an asteroid that has a high chance of hitting us and then try to deflect it using methods that have never been tried before? I'd rather have a test case.

Come to think of it: Can't we make it a little friendly competition?

First the chinese are taking a shot at it with their solar sail and then ESA takes a more literal shot at it and we see which technique works best? That would certainly be interesting.
Ricochet
4.7 / 5 (15) Aug 22, 2011
I think we should fling Mel Gibson at it... but that's just my personal opinion.
bg1
1.7 / 5 (3) Aug 22, 2011
Instead of blowing up the asteroid, what if a nuke was set off close enough to vaporize the surface rapidly enough to create a reaction force that would alter the asteroid's orbit.
eachus
4.8 / 5 (5) Aug 22, 2011
They have done the calculations and claim it's not going to hit us. If this is the case then let's just leave it alone.


You have to understand the current state of things. Apophis will pass extremely close to earth in 2029, but will miss by about 4000 miles. It will come very close again in 2036. How close? Depends on a lot of factors, pressure of sunlight, spin, how much drag Earth's atmosphere causes in 2029 (yes, it is very thin at that altitude, but...), and so on.

So there is a very small window, that if Apophis passes through in 2029, it will hit in 2036. The problem is not so much that we don't know where Apophis will be at its nearest point, but that we don't know where the window will be.

The three sensible approaches are 1) be ready to hit it if we figure it went through the window, 2) hit it hard enough in 2029 or before to insure that it misses the window, 3) get lots better data. Obviously the last one should be combined with one of the others.
Jeddy_Mctedder
1 / 5 (10) Aug 22, 2011
2 fifty megaton fusion nukes, both designs fully tested by the soviets will almost definitely be deployed .

it won't be like the movie armageddon, no one is landing on the asteroid. they will propel themselves into the asteroid by hitting it head on. the combined speed of the asteroid and the nuke missiles which will be designed as bunker busters with depleted uranium breaching heads, will bury these things deep enough for them to begin exploding the asteroid from the inside out.

a 50 megaton nukes is going to do quite a bit of fragmenting to the asteroid. the remaining pieces will not pose as serious a threat as their increased surface area results in many of them exploding in the atmosphere rather than hitting the surface or the ocean.
Pyle
1 / 5 (3) Aug 22, 2011
Back to the proposed method in the article. GSwift said:
Approaching it from behind will give a much more likely chance to intercept it.
That would totally defeat the purpose. The solar sail design by Gong et al seems to be to increase the impact velocity of the interceptor, not to land safely. I think their idea is to knock it off course by hitting it hard enough, rather than blowing it into a million little pieces. I'm with Jeddy on this. Best to drop a bunker buster in and see where the pieces go. This should be a good test, even for a bigger asteroid, to see what our nukes will do.
Isaacsname
2 / 5 (2) Aug 22, 2011
Why not just use a laser/s to vaporise part of it and use that to nudge it off-course ?
Star_Gazer
3.5 / 5 (11) Aug 22, 2011
a 50 megaton nukes is going to do quite a bit of fragmenting to the asteroid. the remaining pieces will not pose as serious a threat as their increased surface area results in many of them exploding in the atmosphere rather than hitting the surface or the ocean.


And many others will cause planet wide bombardment.. and no second chance to move the cloud out of the way.. Great idea..
axemaster
1.8 / 5 (5) Aug 22, 2011
Why not just blow up a few nukes close to it, so it would be gently buffeted aside? A few years in advance, and that small nudge would translate into a very large distance.
Ricochet
1.7 / 5 (6) Aug 22, 2011
We could nudge it, but it might just make it slingshot around something else that'll send it back our way MUCH faster than it already is.
I'm with the nukes. Let's blow it up. And send a satellite after the bombs with a camera and make it a pay-per-view event.
tadchem
2.8 / 5 (5) Aug 22, 2011
The optimal technique for enforcing a course change on an orbiting body depends on its composition. A rubble pile will not respond predictably to explosions. A solid rock could be converted INTO an unpredictable rubble pile by an explosion. Finesse is the better option. Wrapping it up in a Kevlar cobweb attached to an ion drive, maybe?
Nanobanano
3 / 5 (7) Aug 22, 2011
Why not send Dawn on an intercept course for Apophis after it completes the Ceres mission in a few years? It has the ion propulsion after all. Put it in orbit around Apophis.

This would let you get some close-ups of Apophis ahead of time to be able to tell exactly what it's made of and how to deal with it.
Ricochet
1.3 / 5 (3) Aug 22, 2011
It doesn't matter if the cluster of rubble is unpredictable as long as each piece is small enough to ensure vaporization in the atmosphere.
GSwift7
4.1 / 5 (14) Aug 22, 2011
Sory, in my previous comment I was thinking that this is a comet. My bad.

As for detonating a nuke near the asteroid rather than inside it, that would do almost nothing to it. The amount of physical force from a nuke in space is minimal even at short distances. Most of the energy from a nuke is in the form of light. If you've ever seen video of tests here on Earth, the initial flash will peel paint, but won't damage metal under the paint. The physical damage doesn't come until the air pressure shock wave. There would be no such shock wave in space. You might make one side of the asteroid smoke, but it would be inconsequential for the asteroid.
GSwift7
3.5 / 5 (8) Aug 22, 2011
As for the Chinese idea, I can't imagine that a collision would transfer enough energy to do much to a rock bigger than two football fields. That's also assuming that you can manage to score a direct hit, rather than a glancing blow. It's safe to assume that it's irregular in shape and rotating. It'll be impossible to pick an exact spot to impace, so it would be up to random chance whether you hit a flat spot or a sloped surface. That's still assuming that you can guide well enough to get a bullseye.

"Luke, what's wrong? Why have you turned off your targeting computer?"
Ricochet
5 / 5 (7) Aug 22, 2011
"Luke, what's wrong? Why have you turned off your targeting computer?"

"It keeps saying 'A problem has been detected and your system has been shutdown to prevent damage.' I thought you said we converted to Linux!"
Nanobanano
1.3 / 5 (4) Aug 22, 2011
That's still assuming that you can guide well enough to get a bullseye


NASA's space nagivation is incredibly perfect.

The analogy they use for sending the Spirit and Opportunity landers to mars and actually landing successfully in the target zone was that it was like taking a basketball and shooting from San Francisco to New York and hitting nothing but net.

I figure detonating a 50 megaton nuclear device will only change Apophis velocity by about 0.5m/s, even if 100% of the yield went into net thrust...

If done early enough, this could allow the object to totally miss, but you also have to consider future encounters...

0.1m/s and for 25 years would change it's position on the closest encounter by 78,840km or over 12 earth radii...
Silverhill
5 / 5 (6) Aug 22, 2011
NASA's space nagivation is incredibly perfect.
It's getting better, but check out the "Mars Scorecard" (last updated in mid-2007) for an amusing recap of the various attempts to get probes to Mars. As of 2000, the Mars "team" was ahead 20 to 13 -- that is, 20 of 33 attempts to reach Mars had failed.

www.bio.aps.anl.g...ard.html
Graeme
4 / 5 (4) Aug 22, 2011
I reckon it should be steered so it hits the moon. Then it will be out of action permanently rather than coming back for another swipe at the earth every few decades.
hush1
1 / 5 (3) Aug 22, 2011
4000 miles?!
Your maths and pocket calculators (super computers)are not up to the task.
In 2029 pocket calculators and maths may have advanced enough to track the object to your satisfaction. Place a sender on the object in 2029. See if a 'skip stone' scenario presents a possibility for 2036.
'Skip stone' mechanics only depends on how much confidence you have placed in your maths, pocket calculators and sender.

Regardless of outcome, we will see how much confidence was placed where and for what.
malapropism
5 / 5 (10) Aug 22, 2011
I'm not sure if the idea is even feasible for such a large chunk of rock with foreseeable tech but it would be way cool if it could be captured at say L1 instead of either destroying or deflecting it. Depending on what it's got in it it would be not only of amazing scientific value but could also be a trove of minerals for later exploitation. And NASA is supposed to be going to an asteroid after all, what better than a "tame" one for starters?

(I expect I'll get loads of 1's now... bring it on)
hush1
1 / 5 (3) Aug 22, 2011
lol
" I expect..." - malapropism
At the expense of my shame I'll disappoint your expectations.
Eventually, I get over my shame, and you will get over being traumatized for people not meeting your expectations.
jimmie
1.4 / 5 (9) Aug 22, 2011
Great.

Now the Chinese Farmers think they know better.

They better concentrate on fixing the milk and
leave the orbital calculations to the big boys.

See you in 2060 guys. ~ after the Great China Crash.

Please stay away from asteroid before
you screw up the milk again.

JH
Soreed
not rated yet Aug 23, 2011
"There also seems to be some disagreement as to the origin of its name; some suggest that Apophis comes from the ancient Egyptian deity, enemy of the uncreator Ra, Apep. Others suggest its simply a nod to the character Apophis on the television show Stargate SG-1."

Who doesn't know that the character Apophis also got his name from the same Egyptian God? Infact, they have named the character so, to create the illusion of that he actually _is_ the egyptian god himself.
tkjtkj
1 / 5 (1) Aug 23, 2011
...
btw, why are we going to carefully ram an asteroid when an explosive charge achieves a more certain outcome?


One problem is that the 'more certain outcome' of explosive impact creates many many more bodies capable of possibly more damage over a wider area. Thank the forces that be that the Pleiades comet remnants are basically tiny chunks of ice!
Moebius
3 / 5 (4) Aug 23, 2011
I'm for all efforts to move it, as long as the move is AWAY from a collision course.
Ricochet
1 / 5 (1) Aug 23, 2011
4000 miles?!
Your maths and pocket calculators (super computers)are not up to the task.
In 2029 pocket calculators and maths may have advanced enough to track the object to your satisfaction. Place a sender on the object in 2029. See if a 'skip stone' scenario presents a possibility for 2036.
'Skip stone' mechanics only depends on how much confidence you have placed in your maths, pocket calculators and sender.

Regardless of outcome, we will see how much confidence was placed where and for what.

We could also use it to anchor a space elevator...
jtdrexel
1 / 5 (2) Aug 23, 2011
Would it be possible to land a nuke and a drill on the asteroid and place the nuke at some optimal depth within the asteroid. If that's possible, then would detonating the nuke at a specific location and depth both nudge the asteroid and minimize the amount of fragmented pieces as supposed to hitting the asteroid head on and causing severe fragmentation of the entire asteroid?
SteveL
5 / 5 (1) Aug 23, 2011
Any explosion or technique that would include the creation of debris - I'm against. We already have a problem with junk floating around in Earth's orbit. Creating more debris, that cannot be tracked will only make future space-based exploration and development even more hazardous. Let's not make things worse if we can help it.
LKD
1 / 5 (3) Aug 23, 2011
http://www.bio.aps.anl.gov/~dgore/fun/PSL/marsscorecard.html


I have a feeling that Russia is in cahoots with Mars by the report card for the first 15 attempts.
GSwift7
3.7 / 5 (9) Aug 23, 2011
(I expect I'll get loads of 1's now... bring it on)


I think my head might explode or short circuit like the androids on "I Mudd", faced with the liar's paradox, from that comment.

http://en.wikiped.../I,_Mudd

I'd really like to give you a 1, but I am forced to agree with your comment that you deserve a 1, and therefore must give you a, give you a, give a, you, give, give, give.....Ahhhhhhh!
rwinners
3.4 / 5 (5) Aug 23, 2011
How about we try all the alternatives... just for practice.
MRBlizzard
1 / 5 (2) Aug 23, 2011
I expect Apophis to shred within the Roche limit on the first pass. I expect some of the pieces will pass through the keyhole. I fear that they will be big pieces. How do we deal with 5 or 10 dangerous pieces?

Personally, I think it should be bagged (think Kevlar fishing net) several days before first approach, but now it's too late to mount the mission, if it shreds. If it doesn't shred, the bag provides a handle for later solar sails.
Bobamus_Prime
5 / 5 (1) Aug 24, 2011
I'm not sure if the idea is even feasible for such a large chunk of rock with foreseeable tech but ... Depending on what it's got in it it would be not only of amazing scientific value but could also be a trove of minerals for later exploitation.


Lets get to harvesting asteroids already. Quit talking about blowing it up, lets build stuff with it! Thanks for saying what I was thinking Malapropism
GSwift7
2 / 5 (4) Aug 24, 2011
I expect Apophis to shred within the Roche limit on the first pass.


Apophis is almost certainly a solid rocky object. To say that it would be affected by the Roche limit is like saying that a boulder of similar size and composition here on the surface of the Earth should also fall apart. Obviously this does not happen, despite boulders on the surface being much closer to the center of gravity. There are plenty of solid rocky objects here on Earth that do not fall apart under gravity.

Your idea is nonsense.
Fionn_MacTool
1.8 / 5 (5) Aug 24, 2011
The Chinese obviously intend to aim it at the United States!
antialias_physorg
5 / 5 (1) Aug 24, 2011
Would it be possible to land a nuke and a drill on the asteroid and place the nuke at some optimal depth within the asteroid.

Yes. And while we're at it let's add some fretwork and paint it pink. (to be clear: the answer is 'no')

Even if it were yes then using a nuke does not mean you pulverize somethnig. It might just break into a lof of pieces (or just two) and keep on its way.

A nuke could be used on the surface to give it a nudge - but that's about the extent of use a nuke would be. The disadvantage is that a nuke is not a very controllable way of changing its course, and in that respect we want good control (which both an impactor and the chinese idea give)
Pyle
5 / 5 (1) Aug 24, 2011
I think what people are failing to recognize is the vastness of space. The scientists in this proposal calculate that a slight tap, say given by a 10kg probe, against the 46 million ton asteroid is enough to get it to miss the keyhole. Somebody get my scales right, but that is like using a .22 to steer a semi. And it should work. Because the solar system is that big and our Pale Blue Dot is that small in comparison.

Anyway. As ap just said, "a nuke could be used on the surface to give it a nudge". But I think it would be good to try it anyway to better understand what it would do. We should be careful about it, probably better to hit an asteroid that isn't careening toward the planet. But still an experiment that we should do to see what we can resort to in a worst case scenario.

For all the "space junk" and scary tiny little rock litter talk. Nonsense. Again. Space is really really big. I know I've linked this before, but...
www.youtube.com/w...-gs0WoUw
Pyle
4 / 5 (1) Aug 24, 2011
Oh yeah. And landing on an asteroid? Drilling? Attaching solar sails? All of that takes quite a bit of doing. Matching velocity with a rock hurtling through space, without the help of its gravity (i.e. not a planet or substantial moon) is very tricky. Could we do it? We haven't yet. But we are working on it. I'd hate the first time to be an all or nothing though.

If we can do it, I like the idea of chucking asteroids at asteroids so that we're throwing several tons at the incoming rather than puny probes.
rwinners
2.8 / 5 (4) Aug 24, 2011
@Pyle.
We landed a spacecraft on an asteroid way back in 2001. Google Eros. And, I believe, the Chinese have done it more recently.
rwinners
2.3 / 5 (3) Aug 24, 2011
Sorry. It was the Japanese, in 2005.
Pyle
5 / 5 (2) Aug 24, 2011
Missed this yesterday, and kinda late for this thread but...
Universe Today had this kinda related article yesterday:
http://www.univer...re-88384
yyz
5 / 5 (2) Aug 24, 2011
@Pyle'

Thanks for the link (I was about to add it). The discussion seems quite relevant (and detailed) for this NEO topic. Do check it out.
yyz
5 / 5 (2) Aug 24, 2011
FWIW, another recently posted arXiv paper to be published in a Chinese astronomy journal outlines a method for temporarily capturing NEOs: http://arxiv.org/...4767.pdf
Pyle
5 / 5 (2) Aug 25, 2011
yyz, I take note from your forbearance on my earlier comments that I was a little "out there". ;) Your silence speaks volumes.

Great link. It is papers like this that make me really wish I were a grad student instead of a working stiff. How cool would it be to spend several months calculating how to capture a 10 meter chunk of the 4.5 billion year old left overs from the formation of the solar system?

On second thought maybe cool is the wrong word? Sign me up all the same.
antialias_physorg
3.7 / 5 (3) Aug 25, 2011
Matching velocity with a rock hurtling through space, without the help of its gravity (i.e. not a planet or substantial moon) is very tricky. Could we do it? We haven't yet.

We have.

List of craft that have done flybys, impacts and taken samples can be found here:
http://en.wikiped..._targets

The Rosetta probe is currently on the way to orbit a comet:
http://en.wikiped...craft%29

hush1
1 / 5 (2) Aug 25, 2011
No one feels threatens by the moon. Kinetic impact is fine. China's contribution to all of us. Our second moon. What better place to store an artifact of life, if we poo poo our ourselves here on Earth.
yyz
5 / 5 (1) Aug 25, 2011
To antialias' links above of visits to small solar system bodies, I would also add:

Dawn(Vesta): http://en.wikiped...craft%29

NEAR Shoemaker(Eros): http://en.wikiped...hoemaker

These missions are "very tricky" but they have been accomplished.
SteveL
3 / 5 (1) Aug 25, 2011
@Pyle: At one time we thought there was plenty of room for junk in orbit around the Earth. Now the sheer quantity of junk orbiting us is becoming a serious issue for space-based tasking. It won't be the large trackable asteroids like in that video that will kill a mission and people, it will be the small golf-ball sized junk travelling at a relative 50,000 mph which we cannot track that will punch a hole in a space ship and disable its control systems. What seems insignificant today can become a serious issue in some tomorrow.
Gawad
5 / 5 (4) Aug 25, 2011
The Chinese obviously intend to aim it at the United States!

Why would they want to get rid of their biggest customer??
antialias_physorg
4.2 / 5 (5) Aug 26, 2011
Why would they want to get rid of their biggest customer??

And their biggest debtor. Not much chance of getting all that money back if you destroy your debtor

It would be foolish of them to smash an asteroid into what is effectively their property until the US pays off its debt - which seems unlikely to ever happen.
Jeddy_Mctedder
1 / 5 (3) Aug 27, 2011
they should test a nuclear missile dual system on an existing small asteroid or meteor/commet that resembles the threat we face.

ideally, one could find a similar size object moving in a similar direction to earth as the one we are afraid of and just test out a thermonuclear explosion that we denotate directly upon the front surface of the object with a bunker buster. and or with one directly in front of the object, or perhaps to a direction at an angle to the asteroid to steer it away from its current course.

maybe 2 nukes should be sent .one to blow it up, the next to redirect its ( and the pieces of it course. ) the second nuke could be redirected based on the results of the first.

the data from a test like this would be enormously useful. especially if we used 100 megaton thermonuclear devices.

incrediblesolv
not rated yet Aug 27, 2011
I may not be a physiologist however this strikes me as not being useful at all. simplest is usually best. bolt ten titans and a few falcon 9 heavy lift rockets to the blooming thing and steer it away.

Movies anyone?
incrediblesolv
not rated yet Aug 27, 2011
darn thing kept spell checking physics to physiology/ist
Omom
not rated yet Aug 28, 2011
"Yeah, like the ESA and NASA hadn't already considered this as an option. Leave it to the pros, please."

LOL! I'd call Hollywood and have someone re-write the script.
nizzim
not rated yet Aug 28, 2011
Why do people keep saying a "single" nuke? We can launch thousands of nukes at it...I'm sure if it were to for sure be on a collision course the entire earthly population would fire every nuke not just one or two
ubavontuba
1 / 5 (3) Aug 28, 2011
You guys watch too many Hollywood movies.

Blowing it up is a bad idea, as the rubble trajectories will be unpredictable (and therefore potentially even more dangerous). Nukes could "nudge" it, but who really wants the resulting radioactive cloud(s) raining down? And trying to launch, land, fuel, and deploy heavy lift rockets to it is so logistically impracticable as to be impossible.

Therefore, the most practicable solution offered in this thread is to toss Mel Gibson at it.

Of course I don't literally mean we should toss Mel Gibson himself (as beneficial as this at first seems), but rather we should toss stuff at it. Lots and lots of relatively low mass stuff, over time. Preferably, reaction mass (conventional explosives).

Just mass produce a bunch of rockets and launch them at it regularly.

The gravity is low enough that even conventional explosives should (in relatively short order) blow enough mass away (at escape velocities) to effect a sufficient change of momentum.

inkredibro
not rated yet Aug 28, 2011
Any explosion or technique that would include the creation of debris - I'm against. We already have a problem with junk floating around in Earth's orbit. Creating more debris, that cannot be tracked will only make future space-based exploration and development even more hazardous. Let's not make things worse if we can help it.


What happens if we blow it to pieces on it's way back out to the outer solar system after it passes us?
tk1
not rated yet Aug 28, 2011
I'll start worrying in 24 years
georgejmyersjr
not rated yet Aug 28, 2011
The early pc computer space simulation "Outpost" where a number of humans must settle another world in another planetary system, results after humanity's "last chance" project creates numerous dangerous meteors from one large impending asteroid. Just sayin'.
antialias_physorg
1 / 5 (1) Aug 29, 2011
Just sayin'.

Just sayin' what? That you like to play video games? That certainly has given you the skills and insights to be the savior of humanity. Well done.
georgejmyersjr
not rated yet Aug 30, 2011
As a follower of the JAXA successful "solar sail" project I meant to say I thought it would be a splendid idea to implement. As a member of the Planetary Society I watched as the first solar sail experiment, with the assistance of a Russian submarine missile launch "fail" before NASA had one. As commercial space becomes more viable I would hope similar designs might be tried, using less chemical thrust subject to failure on the order of "for want of a nail the kingdom was lost." as meteor punctures don't destroy whole solar sail missions. What's in orbit around "Apophis"?
Dileep_Sathe
1 / 5 (1) Oct 09, 2011
The Chinese proposal of launching a "retrograde" spacecrft to counter the danger of collision with Apophis, indirectly gives a conceptual jolt to the teaching circular motion at the "O" level physics. While teaching this basic topic, we "never consider" two bodies moving in "opposite" direction (anti-clockwise and clockwise). Our (teachers) negligence of this aspect of motion is responsible for grown-up students" contrasting responses to questions of circular motion in conventional exams and in questionnaires. The discovery of "retrograde" exo-planets is also questioning planetary theories. Therefore I think physicists will now focus on this problem of direction in near future. For more information, read my letter in CHANGE, May-June 2008, p. 5, http://changemag....ives/... or feel free to contact me on dvsathe[at]gmail.com.
Ricochet
not rated yet Oct 10, 2011
Technically, anything launched at the asteroid while it's coming at us is "retrograde" to the asteroid... I don't see how that would jolt any circular motion logic. They're just saying that the craft would be on a collision course with the asteroid as opposed to a trajectory going the same general direction designed to catch up to the thing.

Maybe I'm missing something in your comments, but I'm getting the sense that you're saying they don't teach anything about restrograde orbits, when it's well known that you have to use a retrograde orbit to send a spacecraft toward the inner planets of our solar system...
Dileep_Sathe
1 / 5 (1) Oct 21, 2011
Ricochet, I have read your comment on my comment. I think, if you read my letter in CHANGE, May-June 2008, p. 5 (especially the second point, that is Troubling Solar System) my comment will become more clear to you. Feel free to contact me directly, if necessary.
rawa1
1 / 5 (2) Oct 21, 2011
The nuclear explosion may not save us against asteroids

http://news.disco...ids.html

If the explosion of an interceptor nuke will be too small, the asteroid will reform under its mutual gravity again. In general, I'm against such socialistic attempts to affect the asteroid path, until the uncertainty level in determination of their exact path is a much lower, than the effect of various methods of asteroid deflection.

We shouldn't forget, these plans are enforced with limited number of people, who are primarily interested in development of military rocket technology and the fight against asteroids is just an evasion for their activities.
antialias_physorg
1 / 5 (1) Oct 21, 2011
If the explosion of an interceptor nuke will be too small, the asteroid will reform under its mutual gravity again.

So? The point would not be to blow it up (besides: we don't have nukes that can blow up anything that is larger than 100 meters in diameter, anyways)

The point would be to deflect it. If it reforms (on a slightly altered path because of the added impulse of the nuke blast) then that wouldn't matter. Actually that would be very good since it would mean that there would not be a wide swath of 'shrapnel' that could contain large enough objects to reach the Eart's surface or take out a bunch of sattelites.

I'm against such socialistic attempts to affect the asteroid path,

What in the world does any of this has to do with the attribute 'socialistic'?
rawa1
1 / 5 (2) Oct 21, 2011
What in the world does any of this has to do with the attribute 'socialistic'?
China is socialistic country powered with notoriously adventurous government (like all centralist governments). It's not accidental, the ideas about Apophis destruction are generated just with China or Russia countries - not by USA, which still have a much better economical prerequisites for it in general. The Russians aren't capable to maintain even the common ISS operation - but they're already willing to fight with asteroids, whenever they expect some money and political prestige for it. This is simply funny. I don't believe these Asians at all.

http://www.space....eat.html
antialias_physorg
not rated yet Oct 21, 2011
Sooo...just because an idea emanates from scientists in a socialistic country it is a 'socialistic attempt at ...'.

You, sir, are a very confused indvidual.
rawa1
1 / 5 (2) Oct 21, 2011
The Russian plan of Apophis destruction which has been announced before few years was apparently motivated with silent breaking of Outer Space Treaty. The Russians are saying, it will need to test the nuclear rocket for this purpose, which would enable them to spread nuclear devices in the free space for the purpose of "science". Not to say, every testing of nuclear engines in atmosphere is connected with global threat of nuclear pollution at the case of catastrophic failure.

http://en.wikiped...e_Treaty

So, when Russians failed with this plan, they announced the managed mission to Mars, which would use the nuclear engine, again. It's all just about expansion of nuclear arms race into cosmic space - but the people, who don't understand the political motivations of these proclamation will still believe, the China and Russia just want to save the world.
You sir are a very confused individual.
Such response just indicates the lack of arguments from your side..
rawa1
2.3 / 5 (3) Oct 21, 2011
I can assure you, I'm well informed individual in this context. The refinements to the images by the Arecibo Observatory have generated a refined path that reduces the odds of an April 13, 2036 impact to about 1 in 250,000. It means, the Apophis is completely safe for humans with compare to authoritarian centralist government equipped with nuclear technologies.

Even if some risk would exist here, then the uncertainty in Apophis path is much higher, than the uncertainty of the methods, which China wants to use for Apophis deflection. In another words, there is high probability, whatever well minded action of Chinese will just make the things a much worse. If we want test various methods of asteroid destruction/deflection, then we shouldn't use a potentially dangerous asteroid for such game, or we could all become a hostage of some limited group of people, who are out of public control.
rawa1
1 / 5 (3) Oct 21, 2011
BTW If the cold fusion works in the way, as its proponents are claiming (..and the mainstream physics refuses to test obstinately), then the deflection of asteroids would become piece of cake because it provides sufficient energy density for such purpose. So - if we really plant to fight with danger of asteroids seriously, then we should consider this aspect of cold fusion research too.
Pyle
5 / 5 (1) Oct 21, 2011
@ap said:
You sir are a very confused individual.

@Zephyr said:
Such response just indicates the lack of arguments from your side...

The refinements ... have generated a refined path that reduces the odds ... to about 1 in 250,000. It means, the Apophis is completely safe for humans with compare to authoritarian centralist government equipped with nuclear technologies.

Comment worthy of a ten! And then...

Blah, cold fusion, blah blah blah


Proving ap's comment. Or maybe it should be delusional rather than confused. But hey, at least you picked a world saving piece of pseudo science rather than just your aether that isn't. I agree with you though. The research into cold fusion should probably include launching Rossi into the vacuum at Apophis.
rawa1
1 / 5 (2) Oct 21, 2011
The cold fusion research of Rossi is disputable to say at least - but the cold fusion research of peer-reviewed science is simply absent.

The small, but nonzero value is still infinitely-times more valuable, than the pure dumb zero. The mainstream research of cold fusion simply sucks and we just ask, who is responsible for it - and deduce the consequences. How much money (not to say about life environment destruction) we are potentially losing with ignorance of cold fusion research each day? Who will pay for it?

Do you believe, you lost your home during financial crisis because of high oil price and speculations of billionaires? Maybe we forget all these "poor innocent" physicists, who are effectively blocking any research of oil fuel substitutes. We should call the things with their true names.
Ricochet
not rated yet Oct 21, 2011
"Nibiru" is gone, by the way... The comet Elenin broke up. Time for all them doomsday authors to rewrite their books. Quickly, before the holiday shopping season! Don't want your kids to miss out on the fear-inspired rhetoric.
http://www.space....day.html
Pyle
not rated yet Oct 21, 2011
If cheap cold fusion were possible then NOBODY would be able to stop it from becoming a reality. It is either very hard to do, or impossible. My money is on the latter, but hopefully I am wrong. In any event, that was quite a left turn on the two month old asteroid - solar sail article.