Asteroid

An asteroid is a small, solid object in our Solar System, orbiting the Sun. An asteroid is an example of a minor planet (or planetoid), which are much smaller than planets. Most asteroids are believed to be remnants of the protoplanetary disc which were not incorporated into planets during the system's formation. Some asteroids have moons. The vast majority of the asteroids are within the main asteroid belt, with elliptical orbits between those of Mars and Jupiter.

Asteroid exploration

Until the age of space travel, asteroids were merely pinpricks of light in even the largest telescopes and their shapes and terrain remained a mystery.

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The first close-up photographs of asteroid-like objects were taken in 1971 when the Mariner 9 probe imaged Phobos and Deimos, the two small moons of Mars, which are probably captured asteroids. These images revealed the irregular, potato-like shapes of most asteroids, as did subsequent images from the Voyager probes of the small moons of the gas giants.

Related Topics:
Close-up - 1971 - Mariner 9 - Phobos - Deimos - Mars - Voyager - Gas giant

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The first true asteroid to be photographed in close-up was 951 Gaspra in 1991, followed in 1993 by 243 Ida and its moon Dactyl, all of which were imaged by the Galileo probe en route to Jupiter.

Related Topics:
951 Gaspra - 1991 - 1993 - 243 Ida - Dactyl - Galileo probe - Jupiter

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The first dedicated asteroid probe was NEAR Shoemaker, which photographed 253 Mathilde in 1997, before entering into orbit around 433 Eros, finally landing on its surface in 2001.

Related Topics:
NEAR Shoemaker - 253 Mathilde - 1997 - 433 Eros - 2001

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Other asteroids briefly visited by spacecraft en route to other destinations include 9969 Braille (by Deep Space 1 in 1999), and 5535 Annefrank (by Stardust in 2002).

Related Topics:
9969 Braille - Deep Space 1 - 1999 - 5535 Annefrank - Stardust - 2002

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In September 2005, the Japanese Hayabusa probe started studying 25143 Itokawa in detail and will return samples of its surface to earth. Following that, the next asteroid encounters will involve the European Rosetta probe (launched in 2004), which will study 2867 Šteins and 21 Lutetia in 2008 and 2010. NASA is planning to launch the Dawn Mission in 2006, which will orbit both 1 Ceres and 4 Vesta in 2010-2014.

Related Topics:
2005 - Hayabusa - 25143 Itokawa - Rosetta probe - 2004 - 2867 Šteins - 21 Lutetia - 2008 - 2010 - NASA - Dawn Mission - 2006 - 1 Ceres - 4 Vesta - 2014

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