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Moving an asteroid needs bright ideas

Coming up with ways to prevent asteroids hitting the Earth must be a fun job. You get free reign to develop all sorts of crazy plans, playing with science without the worry of practicalities or costs because we’re so far away from trying to make any of these ideas a reality.

The latest proposal for deflecting an asteroid on a collision-course with Earth has to be one of the most creative/insane yet: firing paint at it. MIT graduate student Sung Wook Paek says that launching two huge round of paintballs at an asteroid would not only nudge it slightly off course, but also change the colour of the object so that it reflected more solar radiation, helping to alter its trajectory even further.

This was the winning idea in this year’s annual Move an Asteroid Technical Paper Competition, sponsored by the United Nations’ Space Generation Advisory Council. Previous winners have included proposals to use a cloud of nano-sized spacecraft to create a large artificial drag on the asteroid, or moving it using solar sails to harness the power of the charged particles ejected from sun.

This year’s idea builds on these two previous plans. Using the asteroid Apophis – a 27-gigaton rock due to pass close to Earth in 2029 again in 2036 – as a model, Paek set out plans to cover the 450m-diameter object in five tons of paint.

Based on the asteroid’s period of rotation, he calculated that two rounds of pellets would cover first the front and then the back of the rock with a fine, five-micrometer-layer of paint.

How might one encourage such a deflection? The answer, according to an MIT graduate student: with a volley or two of space-launched paintballs.

Such a plan would need to be carried out with plenty of time to spare, however. Working with research that shows how pressure from the sun’s photons can alter the orbits of geosynchronous satellites, Paek estimated it would take up to 20 years for the cumulative effect of solar radiation pressure knock the asteroid off course.

He did consider some practicalities in his proposal as well. The pellets might have to be manufactured in space as launching them from Earth on a traditional rocket might cause them to rupture. He also noted that the pellets could be filled with aerosols that would also create drag to slow the asteroid down. Plus, painting such a space object would help astronomers track it through the sky.

These kind of ideas do seem inherently fanciful; almost as ridiculous as Bruce Willis using a nuclear weapon to blow up a giant asteroid just in time, with such precision that its two halves glide neatly around the Earth.

But taking my tongue out of my cheek for a moment, we may be getting closer to a time when we could actually put some of these proposals to the test and generate a genuine contingency plan, should one of the several hundred asteroids out there that could do some serious damage threaten the planet.


Source: NASA

Is the danger of asteroids great enough for us to test out ways of defending against them?

Although NASA’s budget has now been capped, its aspirations to send a manned mission to an asteroid set by President Obama two years ago remain in tact, and this summer the agency conducted a 10-day simulation of how astronauts could live and work on an asteroid’s surface.

Plus a group of billionaires earlier this year announced plans to create a commercial space company that would travel to and then mine asteroids for valuable minerals, which could perhaps create another opportunity to test out asteroid-defence plans.

Whether there will ever be agreement that the threat from killer asteroids is big enough to persuade (with words and/or cash) those behind these missions to carry out such proposals is difficult to say.

But if we continue to come up with ideas such as the paintball deflection that offer tailored but relatively cheap solutions to the problem, such a proposition might become much more plausible. Giving free reign to scientists to create crazy plans might not be such a bad idea after all.

Readers' comments (16)

  • Maybe we are looking at asteroids in the wrong way, as a nuisance instead of an asset.
    Ways to bring our outer solar system visitors into safe geostationary orbit may be a better option, then maybe ways to mine and garner the valuable resources could be considered.

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  • Nuclear could be a solution, but not weapons:

    1. You have several landers attach themselves to the roid in question.

    2. Some of the landers are thrusters to stabilise the rotation of the roid.

    3. Another lander contains effectively a nuclear reactor that once deployed is an uncontrolled reaction. Effectively leading to an intentional melt down.

    4. At the top of this lander is effectively a pressure vessel and a rocket nozzle, as the fissile material melts into the roid it will release gases which are ejected from the rocket nozzle creating thrust, moving the roid. The gas pressure will also push the fissle material into the roid.

    There is a secondary benefit that if the rocket mechanism fails or the 'tunnel' created by the fissile material collapses the system should continue to create heat and pressure inside the roid until it either blows itself apart, or the thrust comes out a different area.

    The external thrusters could then be used to adjust the direction of thrust to continue the process or the roid has been reduced to smaller chunks.

    Ok, you haven't got Bruce Willis risking his life, but it would be simpler than trying to drill to use Nuclear weapons or adding rocketry systems to move the roid.

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  • Old SciFi idea.... Join two asteroids with a cable, place plasma engines on each to generate a spin about a central point and then when the asteroids are moving at the right velocity, cut the cable. The plasma drives could be left unnatended for decades using the asteroid itself as fuel until sufficient velocity is acheived. One heads into a geostationary orbit around earth, the other dissappears into the oort cloud somewhere. (Or both are moved to a safer solar orbit). If the Earth bound asteroid is a metal, water or carbon based lump, then we have free materials for our space habitats etc.

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  • Thanks JohnK. At last, a workable solution! All we need is sufficient Dilithium crystals. Maybe the asteroid has some? Or we use a variation on a previous idea & paint the Earth black instead? Then the aliens steering the asteroid won't be able to see us. Is it me, or has this magazine gone downhill since ceasing to appear in print?

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  • JoeK.
    Not sure if you were being whimsical about my suggestion, which I cannot claim originality for as it is brazenly copied from an old story I read. The most famous use of this type of idea was probably Isaac Asimov's "The Martian Way".

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  • I agree that radiation pressure using microwaves will work. However, I emphasize that placing a larger array of microwave generating satellites in orbit might be more useful than a ground station. No clouds, no night, just generate.

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