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 |  | Defending Earth: Fact Vs. Fiction
By Michael Paine
Special to SPACE.com
posted: 06:23 am ET
11 February 2000
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asteroid_defense_000211
First, the good news: Asteroid 433 Eros is not on a collision course with the Earth.
| | | CHASING ASTEROIDS: Previous spacecraft missions to asteroids and comets have involved quick flybys with no attempt to match speed with the object. In the future, vehicles will try to land on their surfaces. [more] | 
TO NUKE OR TO NUDGE? Blowing up asteroids may work in the movies, but in reality it could lead to bigger problems. However, nuclear warheads could be used to alter the course of an errant asteroid or comet. [more] |
SAILING WITH SUNLIGHT: From solar-powered cannons to steering an asteroid away from Earth with giant solar sails, the alternatives to blowing up space objects are cutting edge. [more] |
At roughly twice the size of Manhattan Island, Eros is huge compared with other known near-Earth asteroids. A collision by an object this size would be more devastating than the impact that is thought to have finished off the dinosaurs 65 million years ago.
Eros is in the news because, on Monday, after a torturous four-year journey, the NEAR spacecraft will attempt to become an artificial moon of Eros. A successful NEAR mission to Eros will show that we have the ability to rendezvous with an asteroid, and to orbit it.
This ability is crucial if -- some scientists would say "when" -- an asteroid is discovered to be on a collision course with Earth.
Space missions to asteroids and comets might not seem as exciting as a landing on Mars, but the social, scientific and commercial benefits from these missions could be great. An asteroid or comet impact with Earth is the only type of natural disaster that could instantly wipe out human civilization, and yet -- unlike earthquakes, floods and volcanoes -- it is within our grasp to prevent the collision.
The know-how needed to protect Earth from collision could also be used for commercial mining in space. Comets and asteroids are packed with useful raw materials. Eventually, space prospectors might want to rendezvous with them and, perhaps, change their orbit.
SPACE MISSIONS: The physical properties of asteroids and comets are still poorly understood. Here is a list of missions to asteroids and comets currently underway or being planned to learn more about these celestial bodies.
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