NASA Formalizes Asteroid Defense Plan

The Planetary Defense Coordination Office will characterize asteroids and comets that pass near Earth’s orbit around the Sun.


Lindley Johnson has an enviable job title as the first person whose resume will bear the line: “NASA Designated Planetary Defense Officer.”

Johnson is the tip of a very big iceberg of awesome as NASA has formalized its program for detecting and tracking near-Earth objects (“NEOs”) under the name title of the Planetary Defense Coordination Office. The new office will be responsible for all of NASA’s projects to find and characterize asteroids and comets that pass near the trajectory of Earth’s orbit.

And if any threats are detected, it will be the office’s role to coordinate a response.

“Asteroid detection, tracking and defense of our planet is something that NASA, its interagency partners, and the global community take very seriously,” said John Grunsfeld, associate administrator for NASA’s Science Mission Directorate in Washington, said in the office’s announcement. “While there are no known impact threats at this time, the 2013 Chelyabinsk super-fireball and the recent Halloween Asteroid’s close approach remind us of why we need to remain vigilant and keep our eyes to the sky.”

It has its work cut out for it. Since NASA started funding surveys in 1998, more than 13,500 near-Earth objects have been discovered with about 1,500 new ones identified every year. Admittedly, every so often, one buzzes the atmosphere like the 1,300-foot wide asteroid that passed us last Halloween. But others are carrying frozen, usable water we could someday mine for space exploration and use here on Earth.

The federal budget for 2016 includes $50 million for NEO observation and planetary defense. The latter is important, since it doesn’t do us much good to spot an asteroid bigger than a football field hurtling toward us without a plan to deal with it, and “asteroid redirect” concepts are part of the PDCO’s mission.

As the agency noted in its announcement: “Even if intervention is not possible, NASA would provide expert input to FEMA about impact timing, location, and effects to inform emergency response operations. In turn, FEMA would handle the preparations and response planning related to the consequences of atmospheric entry or impact to U.S. communities.”

Here’s how the Planetary Defense office defines a “potentially hazardous” asteroid:

“A potentially hazardous asteroid (PHA) is an asteroid whose orbit is predicted to bring it within 0.05 Astronomical Units (just under 8 million kilometers, or 5 million miles) of Earth’s orbit; and of a size large enough to reach Earth’s surface – that is, greater than around 30 to 50 meters. (Smaller objects entering Earth’s atmosphere tend to disintegrate.) The potential for an asteroid to make a close approach to Earth does not mean that it will impact Earth. By monitoring PHAs and updating their orbits as new observations are made, observers can improve their predictions of Earth impact risk. Sometimes the term potentially hazardous object, or PHO, is used to describe an asteroid, or comet, that meets these criteria.”

If you want to keep track of potential threats for yourself, NASA has a widget that lets you monitor the next five closest approaches to the planet.

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