AIR SPACE

How to Prevent an Asteroid Impact

Russia is considering sending a spacecraft to a large asteroid to knock it off its path and prevent a possible collision with Earth. Just how would we prevent asteroids from colliding with Earth?

Terrestrial Strike

Artist's concept of a catastrophic asteroid impact with the early Earth. An impact with a 500-km-diameter asteroid would effectively sterilize the planet. Russia is considering sending a spacecraft to a large asteroid set to fly near Earth in 2029, to knock the space rock off its path and prevent a possible collision with Earth, the head of the country's space agency said Wednesday.

NASA/Don Davis

Apophis Photographed

NASA scientists recalculated the path asteroid Apophis, seen here, in early October. The refined path indicates a significantly reduced likelihood of a hazardous encounter with Earth in 2036.

UH/IA

Asteroid Eros

The Apophis asteroid is approximately the size of two-and-a-half football fields. It's still too far away to see clearly, but up close would probably look like this this, a color image of Eros taken by NASA on February 12, 2000, at a range of 1100 miles. The image shows approximately the color that Eros would appear to the unaided human eye. Its subtle butterscotch hue is typical of a wide variety of minerals thought to be the major components of many asteroids.

NASA/JPL/JHUAPL

Path of Asteroid Apophis

Initially, Apophis was thought to have a 2.7 percent chance of impacting Earth in 2029. Additional observations of the asteroid in October ruled out any possibility of an impact in 2029. Nevertheless, Russia is considering sending a spacecraft to a large asteroid to knock it off its path and prevent a possible collision with Earth. The asteroid is expected to make a record-setting approach to Earth on Friday, April 13, 2029, when it comes no closer than 18,300 miles above Earth's surface.

JPL/NASA

Impact event

An artist's impression of a major impact event. The collision between Earth and an asteroid a few kilometres in diameter releases as much energy as the simultaneous detonation of several million nuclear bombs.

So how could Earth's scientists prevent such an impact?

A Space Tractor?

One way scientists have proposed to deal with an asteroid impact: a space tractor. Here, an artist's concept of such a tractor towing an Apophis-like asteroid away from a collision course with Earth.

Dan Durda, FIAAA/B612 Foundation

Deep Impact

Another theory on how to deal with potential near earth impacts: Send a satellite out to plant explosives, as graphically illustrated in movies like Deep Impact. Here, a NASA illustration of what such a mission might look like.

NASA

A Solar Sail

Another potential way to mitigate the potential risk of an asteroid impact: Attach a large enough solar sail directly to the cosmic rock, using the pressure of the sun to shift the object's orbit.

NASA/Marshall Space Flight Center

How to Prevent an Asteroid Impact

Russia is considering sending a spacecraft to a large asteroid to knock it off its path and prevent a possible collision with Earth. Just how would we prevent asteroids from colliding with Earth?

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