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- 65803 Didymos on Wikipedia
65803 Didymos
Details
Didymos is the larger member of a binary near-Earth asteroid system and the anchor of NASA’s DART planetary-defense test. In 2022 the spacecraft struck its small moon Dimorphos to change its orbit.
65803 Didymos is the larger member of a binary near-Earth asteroid system, and it became the anchor of humanity’s first planetary-defense experiment. When NASA’s DART spacecraft arrived in September 2022, its DRACO camera returned this close view of Didymos itself just before the encounter resolved both worlds.
Didymos is a stony S-type asteroid, nearly spheroidal but visibly flattened. It spins once every 2.26 hours, fast enough to push loose surface material toward the equator and build a ridge around its middle. Circling it is the small moon Dimorphos, only about 160 metres across, which the larger asteroid keeps on a tight orbit.
DART did not strike Didymos. It deliberately hit Dimorphos, shortening the moon’s orbit around Didymos by about 32 minutes, far beyond the 73-second threshold set for success. The system became the proving ground for the idea that a spacecraft can measurably change an asteroid’s path.
372m
Key facts
- Category
- Asteroids
- Object class
- S-type binary near-Earth asteroid
- Composition
- Silicate (stony) rock
- Scale fact
- 851 mmaximum extent
- Mass
- ~520 million tonnes
Scale context
Where 65803 Didymos sits on the full axis
By size on the journey, 65803 Didymos sits between 101955 Bennu and 152830 Dinkinesh. The band below uses nearby Asteroids objects for context.
Shared physical scale
3.63km
Together, these objects make the size change around 65803 Didymos easy to compare at a glance.
Sources
References for 65803 Didymos
Measurements and descriptive context are compiled by the Scale of Space team from the references below. If you find an error, please let us know.
- 65803 Didymos — Wikipedia
- Visual reference: Wikimedia Commons (NASA / Johns Hopkins APL, Public domain)
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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 turn parts of that scale into curated essays, while focused views let you explore the same range through specific groups of objects.