243 Ida

Also known as (243) Ida, Ida

main-belt asteroid

AI overview

243 Ida is a rocky asteroid located in the main belt between Mars and Jupiter. It's notable because it was visited by a spacecraft in 1993 and was found to have its own small moon orbiting it, helping scientists better understand the structure and composition of asteroids.

AI-generated from the Wikipedia summary — may contain errors.

Picture of the Day · NASA

Pathfinder on Mars

2026-07-04

On July 4th, 1997, using its own array of fireworks, a parachute, and a cocoon of airbags, the Mars Pathfinder spacecraft bounced like a giant beach ball at least 15 times before it came to rest on the surface of Mars at 10:07 AM Pacific Daylight Time. After its then novel airbag-assisted landing sequence was completed, Pathfinder transmitted this color mosaic to mission operators on Earth. In the scene from another world, the Mars Sojourner robot rover is visible in the foreground, crouched on top of the unfolded Pathfinder. About the size of a large house cat, the six-wheeled, solar-powered Sojourner became the first successful Martian rover. Surrounding Pathfinder are deflated airbags and the rock-strewn terrain of the Ares Vallis floodplain. In the distance Martian hills appear against a dusty brownish sky. The Pathfinder lander was subsequently renamed the Carl Sagan Memorial Station.

via NASA APOD

Wikidata facts

Diameter: 32
Radius: 15.7
Mass: 42000000000000000
Orbital period: 1768.994774518883
Image: 243 ida crop.jpg

Show 21 more facts

Commons category: 243 Ida
provisional designation: A884 SB
time of discovery or invention: 1884-09-29
Commons gallery: (243) Ida
orbital inclination: 1.130114887490663
albedo: 0.262
temperature: 200
rotation period: 4.634
density: 2.6
surface gravity: 1.1
right ascension: 168.76
declination: -2.88
absolute magnitude: 10.08
orbital eccentricity: 0.04554826377288688
semi-major axis of an orbit: 2.862543414671485
periapsis: 2.732159532158688
apoapsis: 2.992927297184282
longitude of ascending node: 323.5483160421322
argument of periapsis: 113.7885216058694
mean anomaly: 8.484984861571803
time of periapsis: 2460958.805850328

Sources (6)

via Wikidata · CC0

~26 min read

Article

243 Ida is an asteroid in the Koronis family of the asteroid belt. It was discovered on 29 September 1884 by Austrian astronomer Johann Palisa at Vienna Observatory and named after a nymph from Greek mythology. Later telescopic observations categorized Ida as an S-type asteroid, the most numerous type in the inner asteroid belt. On 28 August 1993, Ida was visited by the uncrewed Galileo spacecraft while en route to Jupiter. It was the second asteroid visited by a spacecraft and the first found to have a natural satellite.

Ida's orbit lies between the planets Mars and Jupiter, like all main-belt asteroids. Its orbital period is 4.84 years, and its rotation period is 4.63 hours. Ida has an average diameter of 31.4 km (19.5 mi). It is irregularly shaped and elongated, apparently composed of two large objects connected together. Its surface is one of the most heavily cratered in the Solar System, featuring a wide variety of crater sizes and ages.