Asteroid That Might Hit Earth Next Century to Be Visited by U of A Spacecraft in 2018

The meteor blast over Chelyabinsk, Russia on February 15, 2013, broke windows, temporarily blinded and injured people, and spread tons of rocky debris over a wide area.

It was a heaven-sent marketing coup for asteroid wonks.

Dante Lauretta, Tucson father, University of Arizona professor, and principal investigator (a.k.a. "boss") of OSIRIS-REx, a billion-dollar NASA project to return a sample of an asteroid back to Earth in 2023, remembers the day vividly.

The arrival of the 10,000-ton stony object into Earth's atmosphere that day couldn't have been better timed. In fact, it marked a coincidence of spooky proportions — a reminder of the danger that strikes from above. On that day, there were two space rocks hurtling toward Earth: one that scientists knew about, and the mystery meteoroid.

Spanish astronomers had made a stir with their discovery in February 2012 of the roughly 100-foot-wide asteroid that would be known as DA14 or Duende. The rock quickly was seen as a record-setter. Calculations of its orbit showed that on February 15 of the following year, it would pass nearer to Earth than the orbits of many manmade satellites. Nothing that big ever had been seen coming so close to our planet.

Analysis of Duende's orbit showed that it would not hit Earth in 2013, if ever. But it was a good opportunity for NASA to talk about OSIRIS-REx and the important taxpayer-funded work getting done on asteroids. A year in advance, the agency planned a media event for February 15, with officials from the Goddard Space Flight Center in Maryland. Lauretta, one of the experts to be interviewed by news organizations around the country, received some "talking points" from NASA he'd be expected to cover.

"[The space agency] said, 'This asteroid's not going to hit the Earth. It's not going to hit the space station. It's not going to hit anything we need to worry about,'" Lauretta says now.

He went over the material in a round of live shots, appearing on one local station after another, answering the same basic questions, with the main theme being: "We are safe."

But while he was on the air, another story in the Russian city of Chelyabinsk led news stations. This story also was about an asteroid. But it had audio recordings of loud booms, dash-cam shots of smoke trails in a blue sky, and news footage of broken windows and kids crying.

The Chelyabinsk "impactor" later was estimated to have been about 65 feet wide, nearly as big as Duende. But it was on a whole different trajectory and wasn't related to Duende. It had come in from the direction of the sun, hidden in the glare. An expert review of millions of telescopic images taken in the weeks leading up to the impact showed no sign of the asteroid. It had flown over the Ural Mountains just before dawn and exploded about 20 miles high with the energy equivalent of roughly 500 kilotons of TNT, or 30 times the strength of the Hiroshima bomb.

It caused $33 million in damage, knocking out the windows of thousands of apartment buildings and causing the roof of a factory to cave in. About 1,200 people ended up in hospitals with injuries including cuts from glass and skin and retina burns.

Had the rock been made of a more air-penetrating metallic composition, detonated at a much lower altitude, or come in at a steeper angle, the city of more than a million people would have fared much worse, scientists believe.

A month later, Lauretta found himself giving seminars about the OSIRIS-REx project to the White House Office of Science and Technology Policy and to the House Science, Space, and Technology Committee. A favorite prop of everyone at these events was the passing around of a fragment of the Chelyabinsk meteorite. (The "-ite" gets added to these objects once they're on the ground.) The biggest known impact from space since the 1908 Tunguska event in Siberia had brought the issue of asteroids into sharp, mainstream focus.

"All of a sudden, the politicians know who we are and think we're important," Lauretta says with a grin from his office at the U of A's Michael J. Drake Building in Tucson, where researchers and students are building scientific instruments that in two years will start flying to asteroid Bennu.

Featuring the disaster-movie angle of comets and asteroids is one way to get attention for expensive space missions — but it's not hype.

More than 100 tons of space rocks enter the Earth's atmosphere every day, mostly specks of dust or material the size of a grain of sand that burns up in a flash. Every now and then, something larger cruises in.

It's a well-known scenario and a staple of the disaster genre. You've probably seen one of the many this-could-really-happen popcorn flicks about asteroids or comets threatening Earth, including Armageddon, Deep Impact, Meteor, Asteroid, or the one whose plot has Phoenix destroyed, A Fire in the Sky.