The International Academy of Astronautics will hold its first conference on protecting our planet from impacts by asteroids and comets the week of April 27, 2009 in Granada, Spain. The 1st IAA Planetary Defense Conference: Protecting Earth from Asteroids, co-sponsored by the European Space Agency and The Aerospace Corporation, is the follow-on to two previous planetary defense conferences held in 2004 in Los Angeles and 2007 in Washington, D.C. Details on the 2004 and 2007 conferences are at www.planetarydefense.info

The 2009 conference will bring together worldwide experts to discuss:

• Detecting and tracking asteroids and comets that might be hazardous to our planet,
• Characteristics of these objects,
• Deflecting a threatening object should one be detected,
• The nature of impact disasters, and
• Political, legal and policy issues that must be considered as part of an overall mitigation strategy.

At present, there are over 900 asteroids and comets that are designated Potentially Hazardous Objects (PHOs), objects larger than about 140 meters that could eventually threaten Earth. Ground-based observations are currently increasing this number by more than 80 per year. Experts believe that the total population of PHOs could number 4000 or more.

A particular focus of the conference will be Apophis, a 270-meter asteroid discovered in 2004 that is predicted to pass very close to Earth, below the altitude of our geosynchronous satellites, in April 2029 and has a current probability of impacting our planet in 2036 of 1 in 45000. The most recent significant impact occurred in Siberia, Russia, in 1908 when an object estimated to be between 30 and 50 meters in diameter entered the atmosphere and exploded. The blast leveled over 2000 square kilometers of forest—an area larger than Washington, D.C.

More and more evidence confirms that impacts by asteroids and comets are not uncommon and that even relatively small objects can cause local and regional disasters. If we are to be in a position to act for a later, and closer, approach of Apophis, or any other close approach or potential impact, we need to both broaden the knowledge base and increase the range of scientific disciplines involved in planetary defense.

We have the technology to prevent such a disaster, but what would actually be required to be sure we deflect a threatening object? And will we see it coming and be ready to make a decision to act? The conference will disseminate a wide range of the latest information related to planetary defense and will help answer these questions.