Scientists study how to push monster asteroid with chance of hitting Earth off course

Scientists study how to push monster asteroid with chance of hitting Earth off course

Bennu is a big asteroid. Really big.

Scientists estimate that it's more than five football fields in diameter and weighs more 87 million tons.

And in 117 years, it's got a 1-in-2,700 chance of hitting Earth, setting off an impact that would be 80,000 times stronger than the Hiroshima bomb.

If you're worried, don't be (at least not much).

Not only are the chances that the asteroid might hit the Earth slim, scientists are already working on a plan to deflect it.

That's right. Think "Armaggeddon" in real life.

In a recently-published study, a "national planetary defense team" described how it designed a conceptual spacecraft aimed at deflecting Earth-bound asteroids.

The 30-foot-tall craft — called HAMMER (Hypervelocity Asteroid Mitigation Mission for Emergency Response vehicle) — would act as a battering ram or as a transport vehicle for a nuclear device.

But would it work to nudge Bennu off its course? Maybe.

The study looked at a number of deflection scenarios, ranging from launching 10 years before impact to 25 years before.

In the 10-year scenarios, the study found, it would take 34 to 53 launches of a heavy rocket (each carrying a single HAMMER) to deflect the asteroid enough to miss the Earth. If the Earth had 25 years, the number of launches would drop from seven to 11.

A single HAMMER used as a battering ram wouldn't deflect an object like Bennu, the study concluded. And the study's authors say the "nuclear option" might be the only option in pushing an asteroid as big as Bennu off course.

So why study this to begin with?

"The chance of an impact appears slim now, but the consequences would be dire," said Kirsten Howley, Lawrence Livermore National Laboratory physicist and co-author on the paper, which appeared in Acta Astronautica.

"This study aims to help us shorten the response timeline when we do see a clear and present danger so we can have more options to deflect it. The ultimate goal is to be ready to protect life on Earth."

The planetary defense team studying how to handle asteroids that could impact Earth are planning two more studies. Meanwhile, a NASA team is also in the midst of an unmanned space mission to get samples from the asteroid.

University of Hawaii scientist David Trang is among those helping with that flight, which aims to gather important data about the behemoth of a celestial body. The OSIRIS-REx spacecraft is set to arrive at Bennu in August and begin surveying the surface.

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