Robot launched to Bennu, the asteroid that could hit Earth in 2187

Researchers don't yet understand much about Bennu, an almost-black asteroid scientists believe has remained largely unchanged for 4.5 billion years.

What is known is that the 500-metre "rubble-pile" is a NEO, or Near Earth Object, and that its path around the sun intersects with Earth's orbit and brings it near this planet every few years.

Andrew Fazekas, a science writer and blogger at "The Night Sky Guy," said Bennu has a one in 1,800 chance of hitting Earth in the year 2187.

"So it's something we want to keep an eye on," says Fazekas.

Bennu is "a pretty hefty object," according to the science writer.

"It could destroy an entire city quite easily if it had a direct impact," he said.

In addition to potentially destroying major metropolitan areas or, if, the it landed in the sea, causing massive tsunamis, Fazekas says the asteroid is also "full of minerals and precious metals," which could in the distant future be collected by mining operations.

Robot space geologist

On Thursday, a robotic spacecraft OSIRIS-REx — or the Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer — blasts off from Cape Canaveral on a seven-year round trip to find out more about Bennu.

The two-tonne robot will grab chunks of the asteroid's surface and bring it back to earth for analysis.

Once studied, the asteroid bits could reveal new information about the formation of the solar system.

"This is really what astronomers are calling a smash-and-grab mission," says Fazekas.

OSIRIS-REx will arrive back in 2023, "hopefully [with] a wonderful stash of pristine asteroid material," says Fazekas.

Asteroids, he explains, are "leftover remnants from the formation of the solar system": billion of bits of rubble that failed to become moons or planets and moon, and now orbit the solar system.

"These are ancient relics," says Fazekas.

"Some of them date back 4.5 billion years. So for astronomers, it's a scientific boon to be able to scoop up and analyze some of this material."

Canadian laser

OSIRIS-REx is equipped with a Canadian-made laser altimeter, an instrument used to map the asteroid.

"Our Canadian instrument will create a cartography map at exquisitely high resolutions like never before on missions in the solar system," says Fazekas.

"It also allows us to bring the spacecraft safely down to the asteroid, within only a few metres, so that we can stretch out our robotic arm and scoop up some samples."

In return, Canada will receive four per cent of the samples, which will "be a boon for many researchers across the country," says Fazekas.

"This is going to be exciting stuff," he says.

He added that through the sample analysis, scientists could better "understand the recipe to make an asteroid, and also the recipe to make planets like Earth."

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Back to the asteroid issue

OSIRIS-REx will, hopefully, also collect data about what the Earth-adjacent asteroid is made out of, thereby reducing the chances of it laying waste to Earth cities in 171 years.

"Right now, the chances [of Bennu colliding with earth] are 1 in 1,800," says Fazekas.

"But with this mission, those chances will hopefully get slimmer."

He adds the research will help scientists answer certain pressing questions.

"What do we do? Launch a mission to nudge it over? Explode the asteroid like in the Hollywood movies? What do we want to do with this asteroid?" he said.

"This mission will help us determine that."