Planetary Defense
Planetary Defense refers to the strategies and measures designed to protect Earth from potential collisions with Near-Earth objects (NEOs) such as asteroids or comets. This field of study and practice has grown in importance due to the potential catastrophic consequences of an NEO impact, which could lead to significant loss of life and property damage.
History
- Early Awareness: The concept of planetary defense was first brought to the public's attention after the Tunguska event in 1908, where a large explosion over Siberia, now thought to be caused by an airburst of a meteoroid, flattened hundreds of square kilometers of forest. This event underscored the potential threat from NEOs.
- Space Age: The launch of Sputnik in 1957 marked the beginning of space exploration, and with it, the capability to detect and track NEOs. The development of technologies like radar and telescopes in space further advanced our ability to monitor these objects.
- Modern Efforts:
- NASA established the Near-Earth Object Observations Program in 1998, following the mandate from the U.S. Congress to find and track 90% of NEOs larger than 1 km in diameter that could pose a threat to Earth.
- The European Space Agency (ESA) has also been involved, with projects like NEOMAP (Near Earth Object Modelling and Planning).
- In 2016, NASA's DART mission (Double Asteroid Redirection Test) was announced, aiming to test the kinetic impactor technique for asteroid deflection.
Strategies for Planetary Defense
- Monitoring and Detection: Continuous surveillance using ground-based and space-based telescopes to identify and track NEOs.
- Deflection Techniques:
- Kinetic Impactor: Sending a spacecraft to collide with the NEO to change its trajectory.
- Gravity Tractor: A spacecraft uses its gravitational force to slowly alter the path of the NEO over time.
- Ion Beam Shepherd: Using ion propulsion to gently push or pull an asteroid off its collision course.
- Nuclear Options: Detonating a nuclear device near or on the NEO to alter its course or break it into smaller, less harmful pieces.
- Mitigation: If deflection is not possible, strategies include evacuation plans, impact mitigation through infrastructure hardening, and emergency response preparation.
Current Status
Sources
See Also