Near-Earth objects (NEOs) are asteroids or comets with sizes ranging from meters to tens of kilometres that orbit the Sun and whose orbits come close to that of Earth's. Of the more than 600 000 known asteroids in our Solar System, almost 10 000 are NEOs.
An example of a near-Earth object is 25143 Itokawa, an object about 300 m in diameter that was visited by the Japanese spacecraft Hayabusain 2005.
NEOs could potentially hit our planet and, depending on their size, produce considerable damage. While the chance of a large object hitting the Earth is very small, it would produce a great deal of destruction; thus NEOs merit active detection and tracking efforts.
The goal of SSA's Near-Earth Object Segment (SSA-NEO) is to:
* Become aware of the current and future position of NEOs relative to our planet
* Estimate the likelihood of Earth impacts
* Assess the consequences of any possible impact
* Develop NEO deflection methods
The NEO Segment observes NEOs, predicts their orbits, produces impact warnings when necessary and is involved in potential mitigation measures.
The SSA-NEO system is based on syndicating and federating observation and tracking data provided by a large number of European and international sources.
The key components include:
* Observatories and astronomers with telescopes of various sizes, both professional and amateur
* A central SSA NEO Coordination Centre (to evolve into the 'Small Bodies Data Centre'), which uses astrometric measurements collected by the Minor Planet Center (USA)
* An analysis capability to predict possible impact locations and assess dangers
* Analyses related to risk mitigation, including the possible deflection of an asteroid
* A system for issuing warnings and alerts to civil authorities in Europe
Data on NEOs are collected from telescopes and radar systems worldwide. Each of these submit observations to the Minor Planet Center (MPC), operated by the International...