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UA Strong Ally in NASA's Call to Find Dangerous Asteroids

University Communications, June 30, 2013

NASA has issued an "Asteroid Grand Challenge" focused on finding all asteroids that could present a threat to Earth.

The initiative, aimed at partners in national and international government, industry, academia and with citizen scientists, includes the University of Arizona with its unsurpassed track record in asteroid hunting, a citizen science asteroid program recently awarded with a White House award and leadership in the first NASA mission to return a sample from a potentially hazardous asteroid.

When it comes to potentially hazardous asteroids, NASA officials say, mankind is well advised to sweat the small stuff.

While scientists say that 95 percent of asteroids larger than one kilometer have been discovered, countless small, difficult-to-spot space rocks are whirling through space, with an unknown number possibly tumbling along a collision course with Earth.

The fireball that blew up over Chelyabinsk in Russia in February 2013 served as a reminder that even a house-sized object can unleash a blast capable of injuring about 1,500 people – in this case, mostly from shattered glass caused by the air blast – if it goes undetected until it plunges into the Earth's atmosphere.

In addition to high-tech detection methods and developing a spacecraft capable of rendezvousing with an asteroid in deep space, UA researchers also pursue programs that aid in the hunt for the next threat and enlist citizen scientists in characterizing asteroids.

The UA's Catalina Sky Survey remains the most productive asteroid-discovery program operating today, finding new near-Earth objects at a rate of around 600 per year. NASA's Near Earth Object (NEO) Program lists the Catalina Sky Survey as "currently the most efficient NEO survey program for finding new near-Earth objects."

"Nobody has discovered more asteroids than we have," said Tim Swindle, head of the UA’s Department of Planetary Sciences in the College of Science, referring to Spacewatch and the Catalina Sky Survey, both programs created at the UA to find and track asteroids that could pose a threat to Earth. "As far as asteroids go, we are the university that does asteroids more than anybody else."

The Catalina Sky Survey is also the most sensitive survey for finding small near-Earth asteroids in the 15 to 30-foot size range, which are candidate targets for NASA's Asteroid Redirect Mission (ARM), according to Eric Christensen, the Survey’s newly appointed principal investigator.

Christensen said ARM targets – small asteroids in Earth-like orbits – are difficult to discover due to their small size and the fact that they are only "discoverable" for as little as a few days before they fade.

"The current rate of discovery for these kinds of objects is too low to find enough good candidates for ARM mission planning" Christensen explained. "It needs to increase by a factor of at least 10 to support such a mission. The Catalina Sky Survey is currently in the midst of upgrades to both of our survey telescopes on Mt. Lemmon, which will increase their overall capability and their sensitivity to ARM candidate targets."

"As we keep getting better at finding these things, we discover that such close approaches happen more frequently than you might think," said Ed Beshore, former director of the Catalina Sky Survey, about object 2012 DA14, better known as the "Valentine asteroid," which buzzed the Earth on February 15 at a distance of about 17,200 miles or 27,680 kilometers, closer than geostationary satellite orbit.

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