Saturday, December 05, 2009

To Deflect an Asteroid, Try a Lasso, Not a Nuke

By Adam Mann
To save the world from the real threat of a major asteroid impact, one engineer has imagined a scheme similar to George Bailey’s wish to lasso the moon for his sweetheart in “It’s a Wonderful Life.”
The plan is to attach a gigantic weight to an Earth-bound asteroid using an enormous cord. This crazy-sounding contraption would change the asteroid’s center of mass and subsequently its trajectory, averting a potentially catastrophic scenario.
Aerospace engineer Major David French of the Air Force Institute of Technology mathematically modeled how different weights and lengths of tether would affect a killer asteroid’s orbit over time. The results are in the December issue of Acta Astronautica.
He found that, in general, longer tethers and larger masses would more significantly change the asteroid’s orbit. The alteration would occur slowly, taking anywhere from 10 to 50 years.
The technique would require no simple mission. The cosmic counterweight would tip the scale at billions of pounds, while the rope would range anywhere from six miles (about the height of Mount Everest), to 60,000 miles (long enough to wrap around Earth two and a half times).
This solution may sound unrealistic, but the threat is real. To date, NASA’s Near Earth Object Program, which tracks asteroids and comets that could approach the planet, has cataloged more than 5,500 objects. About 1,000 of these are classified as “potentially hazardous,” meaning they could wipe out a city, spawn giant tsunamis or, in the worst case, eradicate life with a planet-shrouding cloud of debris. Read Entire Article