A satellite, 7 km across and designated S/2003 (379) 1, was discovered on 14 August 2003 by Jean-Luc Margot using the Keck II adaptive optics telescope at Mauna Kea. The moon orbits 3400±11 km away in 80.8±0.36 d with an eccentricity of 0.334±0.075. The system is loosely bound as Huenna has a Hill sphere with a radius of about 20,000 km.