How are NEOs studied?

The study of chemical and physical characteristics of asteroids and comets is very important for three different reasons:

Images and models of asteroid Vesta (Courtesy:NASA)

For this reason NEOs are studied first of all with many scientific instruments. In fact NEOs have the big advantage of being very near to Earth, and so they can be studied not only with classical astronomical instruments (such as telescopes with photograph plates or more recent CCD, spectrometer etc) but also with instruments that aren't often thought to be used in astronomy, such as radars. These scientific studies have obtained many results both on the chemical composition, on the determination of the characteristics and of the structure of NEOs. More recently, the results have led to real computer 3dimensional models of asteroids.

Spacecraft missions are also required to understand the detailed chemical compositions and structure of comets and asteroids. In fact, being NEOs so near to us and belonging to such a big variety of objects, they are very good targets for past and present spacecraft missions (click here to see a detailed presentation of today's space missions on NEOs).

Mission Deep Space 1 (courtesy NASA)