Moving an asteroid needs bright ideas

Senior reporter

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.

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.

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.