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About Hydra
Hydra is the outermost small moon of Pluto, discovered by Hubble in 2005. It has a nearly pure water-ice surface (based on New Horizons 2015 spectra) and, like Nix, rotates chaotically.
Physical Properties
21 km
4.8e16 kg
Orbit
Pluto
38.20177 d
Gallery
Hand-picked mission imagery of Hydra sourced from NASA and partner archives. Click any photo for full resolution and source attribution.
Imagery on this page is provided by the original mission teams. Full attribution terms: Image Rights & Credits.
Sources & Further Reading
- NASA — official mission / factsheet page
- Wikipedia — extensive cross-referenced article
- NASA u2014 Hydra
Numerical values (radius, mass, orbital elements, temperatures) are drawn from NASA NSSDC Planetary Fact Sheets, JPL Horizons, and the JPL Small-Body Database. Last refreshed: 2026-06-08 01:37:02.