Key facts
- Category
- Asteroids
- Object class
- S-type main-belt asteroid
- Mass
- ~42 trillion metric tons
- Scale fact
- 59.8 kmmaximum extent
- Estimated age
- ~4.5 billion years
- Composition
- Silicate rock with metal
243 Ida
59.8 kmmaximum extent
59.8km
Details
243 Ida is the elongated main-belt asteroid that NASA's Galileo spacecraft flew past in 1993, discovering its tiny moon, Dactyl. Ida became the first asteroid known to have a natural satellite.
Galileo photographed Ida on 28 August 1993, the second close asteroid encounter after Gaspra. The images showed an elongated, heavily cratered body about 60 kilometers long. Ida belongs to the Koronis family, fragments of a larger asteroid broken apart by a collision, and months later the same images revealed its small moon Dactyl.
Links
- Preset views
- Wikipedia
- 243 Ida on Wikipedia
- Universe journey
- Asteroid belt & Jupiter
Size neighbors
Objects near 243 Ida on the scale
On the logarithmic size axis, 243 Ida falls between Helene and 253 Mathilde. Compared below with other objects classed as S-type main-belt asteroid.
Shared physical scale
45.7km
Sources
References for 243 Ida
Measurements and descriptive context are compiled by the Scale of Space team from the references below. If you find an error, write to hello@scaleofspace.org.
- 243 Ida on Wikipedia
- Visual reference: Wikimedia Commons (Galileo 1993 / NASA / JPL, Public domain)
Continue with nearby objects or open the full scale.
About
Scale of Space is a scroll-based journey through the universe, placing objects on a single logarithmic scale so you can compare size across an unbroken range.
Guides explain selected parts of that range, while focused views filter the objects by subject.