Artist's conception shows the Near Earth Asteroid Rendezvous (NEAR) spacecraft orbiting an asteroid. credit:  NASA

How To Save the World From Asteroid Impact: Plastic Wrap

Article Updated: 24 Dec , 2015

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Remember a competition we reported on back in April called “Move An Asteroid”? It was an international technical paper competition looking for unique and innovative concepts for how to deflect an asteroid or comet that might be on a collision course for Earth. The winners have been announced and first prize went to Australian PhD student Mary D’Souza who came up with quite a novel concept: wrap the asteroid with reflective sheeting. Such a coating may increase the asteroid’s reflectivity, enabling deflection by solar radiation pressure.

The asteroid in question, known as Apophis, will pass close to Earth in 2029. Although the 207 meter- wide Apophis is not expected to impact Earth, its current trajectory has it approaching Earth no closer than 29,470 km (18,300 miles), which is well inside the orbit of the moon. This, in conjuction with the 100th anniversary of the Tunguska explosion, was the impetus behind the competition.

D’Souza’s paper was titled “A Body Solar Sail Concept for the Deflection of 99942 Apophis.” Her concept involves using a satellite orbiting Apophis to wrap it with ribbons of reflective Mylar sheeting. Covering just half of the asteroid would change its surface from dull to reflective, possibly enough to allow solar pressure to change the asteroid’s trajectory.

“What happens then is light from the sun shines on the body [of the asteroid] so more of it is reflected … and it actually acts to move it away from the sun and the earth,” said D’Souza, a student at University of Queensland’s School of Engineering.

The competition was sponsored by the Space Generation Advisory Council, a group representing youth perspectives on space exploration to the United Nations and national space programs. SGAC said they received submissions to the competition from all over the world. “It is great to see such an interest in this topic from young people all over the world. Hopefully with competitions like this, SGAC can further increase the involvement of youth in this important field of current space research,” said Alex Karl, Co-Chairperson of the SGAC.

By winning the competition, D’Souza will travel to Glasgow at the end of September to present her plan at the International Astronautical Congress.

Second place was awarded to Andrew Bacon of the Department of Electronic and Electrical Engineering at the University of Bath for his paper entitled “The Use of Electromechanical Resonators for the Mitigation of Earth Threatening Asteroids and Comets.” Bacon’s concept involves the use of electromechanical resonators to build up waves within an asteroid or comet that would break it up. He will also present his plan at the IAC.

Sources: Space Generation press release, The Register


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LLDIAZ
Guest
LLDIAZ
August 25, 2008 12:50 PM

How about bombs with freezing agent attached which wouldnt explode but freeze the asteroid. Then if whatever force were to be applied to said asteroid it would shatter into a million peices.

waldo
Guest
waldo
August 25, 2008 3:23 PM

Did anyone suggest attaching a solar sail to the asteroid?

InvaderXan
Member
August 25, 2008 4:34 PM

Actually, a solar sail would do pretty much the same thing as wrapping it in shiny fabric. Both work by radiation pressure.

An alternative tactic could be to effectively paint the asteroid black, which would make use of the Yarkovski effect (which naturally tends to dominate over radiation pressure for objects that size). Same concept, different effect.

Sili
Member
Sili
August 25, 2008 9:45 AM

How would one ensure that the push is in the right direction? It would quite the downer to realise that it gets closer to Earth, once the wrapping’s done.

R2K
Guest
R2K
August 25, 2008 12:59 PM

The only technology we have right now, and will have in the near future, would be fusion bombs.

Not sure why people are trying so hard to figure out something different.

Joe
Guest
Joe
August 25, 2008 10:12 AM

I wonder how much fuel is required to capture an asteroid 200 meters in size going 30.728 KM/s. I mean slow it down to a complete stop.

Joe

stargeezer
Member
stargeezer
August 25, 2008 10:28 AM

If we can deflect it, presumably where we want, why not nudge into a more ‘user friendly’ orbit? Say an orbit around the sun that is close to earths orbit, but not TOO close. Then we could mine or inhabit it. At least we could visit it on flyby to put some scientific instruments on it. Cjeck out the solar system, maybe the Oort cloud. Or how about sending politicians, lawyers and bureaucrats and other ne’re-do-wells on the trip of a lifetime? Seed the universe with life.

hydrazine
Member
hydrazine
August 25, 2008 11:25 AM

@ Sili

Well, if the asteroid *is* going to hit the Earth moving it anywhere would probably move it off target so I guess it shouldn’t matter where it gets pushed. I guess… As long as the pushing starts with enough of a time margin we should be OK.

/Adam

hydrazine
Member
hydrazine
August 25, 2008 11:58 AM
@ Joe First of all the question is incorrectly posed. For one thing we would need to decide to stop the asteroid in relation to what. Second, an asteroid’s size doesn’t necessarily define its mass. And third, which fuel? For this exercise I’m going to assume we are talking about Apophis which has roughly this size and has the mas of 2.1e10kg and for fuel I’ll take regular gasoline. Imparting a speed delta of around 31000000m/s to an object like this takes (mv^2)/2= (2.1e10*31000000^2)/2 which is around 10^25Joules. According to Wikipedia regular gasoline has an energy content of 34.8MJ/litre (en.wikipedia.org/wiki/Petrol#Energy_content) which gives something like 2.9e17 litres of gasoline. So that’s your answer (if the math is right, I’m… Read more »
quantum_flux
Member
August 25, 2008 12:36 PM
Perhaps Tunguska was actually a natural gas explosion caused by abiotic oil seeping out of the ground. By volume the ratio is 2(O2)-1(CH4) 1 megaton = 4.184×10^15 Joules 5-15% methane in air is considered explosive Energy released by methane = 802 Kj/mol = 802×10^3 J/mol 20.92 |TJ| / 802 |Kj/mol| =2.608×10^10 mols of CH4 5.217×10^10 mols of O2 Oxygen in air is 20%, and assuming that 5-15% ratio displaces only the nitrogen. 2.608×10^11 mols of air molecules is involved. If that is uniformly spread out, then assuming 41.4 mol/m^3 for dry air You end up with an explosion requiring approximately 6.301×10^9 m^3 of air/fuel mixture at STP. That’s a cube of about 1.847 kilometers in all directions in… Read more »
quantum_flux
Member
August 25, 2008 12:45 PM
ntoskrnl
Guest
ntoskrnl
August 25, 2008 1:12 PM

Adam, your assumed speed for apohis is too large. mean velocity is 31km/s = 31000m/s. The required energy is according to above formula ~1×10^19 J which is 2,8×10^11 liters of gas.

A shuttle external fuel tank has a storage space of 554m^3 LO2 and 1515m^3 LH2, roughly 2000m^3 altogether = 2 Million liters uncompressed liquid (our gasoline), so it would take 140 thousand external shuttle fuel tanks full of gasoline.

According to wikipedia, a modern refinery ‘requires’ ~ 4 liters crude oil for 1 liter engine gasoline. The US consumes ~ 20 million barrel oil daily = ~ 3.2 billon liters oil daily, that makes 800 million liters gasoline. That means 350days of US gasoline production would be needed.

ntoskrnl
Guest
ntoskrnl
August 25, 2008 1:21 PM

But of course the those figures are plain theroy, no machine can harvest the full potential of chemical energy carriers. the yield by combustion is very poor, the rest is just wasted. and in space, there would’t be any adequate machine to transform the energy of gasoline into an impulse.

Andrew
Member
Andrew
August 25, 2008 1:57 PM

Why are you guys talking about this stuff? How much of a chemical explosive it’ll take to move an asteroid really has a distant relationship to the article at hand.

paul.swanson
Member
paul.swanson
August 25, 2008 2:13 PM

DuddleyFuddle wrote:

“Or how about sending politicians, lawyers and bureaucrats and other ne’re-do-wells on the trip of a lifetime? Seed the universe with life.”

I like this idea! The hot air alone should move the asteroid out of harm’s way. (OK, I know, it won’t work in a vacuum.)

On the other hand, intelligent aliens might not like the idea of Earthlings dumping their garbage in their space.

marcellus
Guest
marcellus
August 25, 2008 11:04 PM

I think everyone is forgetting the most important point. This is an opportunity to send astrosnauts/cosmonauts to an asteroid that is presenting itself for easy access.

Fly a spacecraft (Orion?) to the asteroid, plant laser mirrors, seismomitors and take samples from the body.

If Apophis does hit the resonance keyhole, just put a small engine or solar sail on it and you would never have to worry about it again.

It would be a great dress rehersal for a really big threat.

Michael Paine
Guest
August 25, 2008 4:05 PM

Solar sails and other methods – see
http://www.space.com/businesstechnology/technology/non_nuclear_deflection_000211.html
( http://tinyurl.com/5otmp )
Painting the NEO white or sliver…
“with such a reflector it is hard to steer — it can only apply a force directly away from the sun, which is the least helpful direction” (it would still work, give enough lead-time and some clever calcuations on timing)
In any case, congratulations to Mary and the other competitors.

Nasikabatrachus
Guest
Nasikabatrachus
August 25, 2008 4:26 PM

“I like this idea! The hot air alone should move the asteroid out of harm’s way. (OK, I know, it won’t work in a vacuum.)”

I agree. But for greatest satisfaction, maybe we should ship them all there, but when they get there we use a railgun to shoot them all off one by one at extraordinary velocities in metal tubes. Into Jupiter. And as the asteroid soars out of the solar system, it will carry news of our new utopia to extraterrestrial civilizations along with instructions on how to accomplish the same feat.

Chuck R.
Guest
Chuck R.
August 25, 2008 5:33 PM

Soooooo…..Glad Wrap will prevail?

Sounds like hoopla to me.

Jorge
Guest
August 25, 2008 7:37 PM
The only technology we have right now, and will have in the near future, would be fusion bombs. Not sure why people are trying so hard to figure out something different. Because nuking an asteroid might not work as intended. With nukes you get very different results with relatively small changes in the initial conditions (like how solid the asteroid is, where your bomb explodes, on impact, above the surface, after penetrating, etc.), and you may even cause more havoc than you would if you just let the asteroid hit the planet. The safest way to deflect asteroids seems to be to push them gently out of the way. Of course, this would only work if you had… Read more »
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