Short answers, pulled from the story.
Michael E. Brown spotted the faint smudge of light on the 1st of March, the 28th of May, and the 30th of June 2005 using images from the Keck II telescope. The Central Bureau of Astronomical Telegrams announced the discovery to the world on the 1st of December 2005.
The International Astronomical Union officially named the satellite Namaka on the 17th of September 2008 to honor a water spirit from Hawaiian mythology who is a daughter of the goddess Haumea. Brown's team proposed these names in September 2006 to honor the location where they made their discoveries at Mauna Kea in Hawaii.
Namaka circles the dwarf planet Haumea every 18.3 days at an average distance of roughly 25,000 kilometers. Its path follows a highly elliptical orbit with an eccentricity of about 0.22 that tilts roughly 13 degrees relative to both Haumea's equator and the orbit of its larger sister moon Hiiaka.
Visible light and thermal infrared observations place Namaka's diameter between 170 and 260 kilometers while scientists estimate its mass at approximately 4.9 times 10 to the 19th kilograms. This makes Namaka ten times less massive than Hiiaka and only 0.03 percent as heavy as Haumea itself.
Namaka and Hiiaka likely formed 4.4 billion years ago following a massive collision between two large Kuiper belt objects. This event occurred roughly 77 to 82 million years after the Solar System first came into existence when centrifugal forces ejected icy surface material into orbit around the dwarf planet.