Exploration
The first spacecraft to traverse the asteroid belt was Pioneer 10, which entered the region on July 16, 1972. At the time there was some concern that the debris in the belt would pose a hazard to the spacecraft, but it has since been safely traversed by 11 Earth-based craft without incident. Pioneer 11, Voyagers 1 and 2 and Ulysses passed through the belt without imaging any asteroids. Galileo imaged the asteroid 951 Gaspra in 1991 and 243 Ida in 1993, NEAR imaged 253 Mathilde in 1997, Cassini imaged 2685 Masursky in 2000, Stardust imaged 5535 Annefrank in 2002, New Horizons imaged 132524 APL in 2006, Rosetta imaged 2867 Šteins in 2008, and Dawn has been orbiting Vesta since July 2011. Due to the low density of materials within the belt, the odds of a probe running into an asteroid are now estimated at less than one in a billion.
Most belt asteroids imaged to date have come from brief flyby opportunities by probes headed for other targets. Only the Dawn, NEAR and Hayabusa missions have studied asteroids for a protracted period in orbit and at the surface. Dawn explored Vesta from July 2011 to September 2012, and is currently en route to Ceres for a 2015 rendezvous. If the probe is still operational after examining Ceres, an extended mission could allow additional exploration, possibly a flyby of Pallas.
Read more about this topic: Asteroid Belt
Famous quotes containing the word exploration:
“Typography tended to alter language from a means of perception and exploration to a portable commodity.”
—Marshall McLuhan (1911–1980)
“I call her old. She has one family
Whose claim is good to being settled here
Before the era of colonization,
And before that of exploration even.
John Smith remarked them as he coasted by....”
—Robert Frost (1874–1963)
“The future author is one who discovers that language, the exploration and manipulation of the resources of language, will serve him in winning through to his way.”
—Thornton Wilder (1897–1975)