Planetary Defense at NASA

Near-Earth Objects called NEOs are asteroids and comets that orbit the sun like the planets, but their orbits can bring them into Earth's neighborhood. It can be within 30 million miles of Earth's orbit. In ancient times, asteroids were in direct collide with Earth and killed so many species and some species were completely wiped out from the Earth's surface. Planetary defense means "applied planetary science" to address the NEO impact hazard. 

NASA established the Planetary Defense Coordination Office (PDCO) to manage its ongoing mission of planetary defense. The PDCO:

• Provide early detection of potentially hazardous objects(PHOs)-the subnet of NEOs whose orbits predict they will come within 5 million miles(nearly 8 million kilometers) of  Earth's orbit and with a size enough to damage Earth's surface. It should be 30 meters to 50 meters large to damage Earth's surface.
• Tracks and characterizes identified PHOs and issues warnings of the possible effects of potential impacts.
• Studies strategies and technologies for mitigating PHO impacts.
• Plays the main role in coordinating the U.S. government's planning for response to an actual impact threat.

Astroid collides with Earth's surface

Find

The PDCO sponsors projects through its Near-Earth Object Observations Program that uses a variety of ground and space-based telescopes to search for NEOs, determine their orbits, and measure their physical characteristics and all other characteristics. NASA is developing the NEO Surveyor space telescope optimized for NEO search and characterization to accelerate the discovery of the currently undetected NEOs.

Near-Earth Object surveyor
credits: NASA

Warn

The PDCO is responsible to provide timely and accurate information to the government, the media, and the public on close approaches to Earth by potentially hazardous objects and any potential for impact with Earth. If any PHO is found to produce a significant chance of impacting Earth, the PDCO will provide a notification message for NASA and send it to the Executive Office of the President of the U.S., the U.S. Congress, and other government departments and agencies. The chance of impacting asteroids with Earth is greater than 1 percent over the next 50 years.

Near-Earth Objects

Coordinate

The PDCO works with other government agencies to develop and update a National NEO Preparedness Strategy and Action Plan for incoming threats. The PDCO also provides expert input on the nature and effects of asteroid impacts to the Federal Emergency Management Agency(FEMA). So that adequate emergency response can be prepared in the event of a PHO impact that is not possible to avoid.

The PDCO also coordinates efforts with the space agencies of other nations as a member of the multinational International Asteroid Warning Network and the Space Missions Planning Advisory Group, under the endorsement of the United Nations Committee on the Peaceful Uses of Outer Space. Nasa recognized its Near Earth Object Observations Program and established a Planetary Defense Coordination Office in January 2016 in response to the NASA Office of Inspector General's 2014 report, "NASA's Efforts to Identify Near-Earth Objects and Mitigate Hazards.".

NASA's Efforts to Identify Near-Earth Objects and Mitigate Hazards report: https://oig.nasa.gov/docs/IG-14-030.pdf

Mitigate

The PDCO sponsors studies of technologies and techniques for the deflection of an asteroid off a predicted impact course with Earth. It is developing missions to demonstrate those technologies and determine their effectiveness if these techniques must be utilized against a predicted asteroid impact threat.

Below video about all known asteroids in our solar system between 1999 and 2018. 

NASA's DART Mission

DART which means Double Asteroid Redirection Test is a spacecraft designed to impact an asteroid as a test of the technology. DART's target asteroid is not a threat to Earth.Read More...