243 Ida

Asteroid 243 Ida is a notable member of the asteroid belt located between Mars and Jupiter. Discovered by Austrian astronomer Johann Palisa on September 29, 1884, Ida is a relatively large asteroid with dimensions approximately 52 kilometers (32 miles) long, 24 kilometers (15 miles) wide, and 15 kilometers (9 miles) thick. This asteroid orbits the Sun at an average distance of about 426 million kilometers (265 million miles) and completes an orbit roughly every 4.8 Earth years. Ida gained significant attention due to the historic flyby of the NASA spacecraft Galileo in 1993, becoming the first asteroid ever encountered by a spacecraft. During this flyby, Galileo discovered that Ida has a moon, subsequently named Dactyl, making Ida the first asteroid known to have a natural satellite. The encounter provided detailed images and data, revealing Ida's elongated shape and numerous craters on its surface, contributing valuable insights into the morphology and characteristics of asteroids in the asteroid belt.