Leonard David continues to report from this week’s planetary defense conference in Garden Grove, CA.

The consensus? We need to get more serious about this threat.

NASA now supports — in collaboration with the United States Air Force — the Spaceguard Survey and its goal of discovering and tracking 90 percent of the Near Earth Asteroids (NEAs) with a diameter greater than about one-half mile (1 kilometer) by 2008. If one of these big bruisers were to strike our planet, it would spark catastrophic global effects that would include severe regional devastation and global climate change.

By charting the whereabouts of these celestial objects, it is anticipated that decades of warning time is likely if one of the large-sized space boulders was found to be on a heading that intersects Earth.

But a uniform message from the experts attending this week’s planetary defense gathering is extending the survey to spot smaller objects, down to some 500 feet (150 meters) in diameter. These asteroids can wreak havoc too, but on a more localized scale.

For instance, if one of these smaller asteroids were to strike along the California coast, millions of people might be killed, Morrison said. A little further to the east, he added, “a nice crater out in the desert” would become a tourist attraction…

…Developing a viable mitigation campaign, Yeomans explained, demands three prerequisites: “You need to find them early. You need to find them early. And we need to find them early.”

This needs to be more closely coordinated with the president’s new space policy, both programmatically and politically.