Short answers, pulled from the story.
Namaka was discovered in the fall of 2005 by Michael E. Brown and the W. M. Keck Observatory adaptive optics team, working from images taken at Mauna Kea, Hawaii. The Central Bureau of Astronomical Telegrams announced the discovery on the 1st of December 2005.
Namaka is named after Nāmaka, a water spirit and daughter of the fertility goddess Haumea in Hawaiian mythology. The International Astronomical Union made the name official on the 17th of September 2008.
Namaka's diameter is most likely near 150 km, about half the diameter of Hiiaka. Its mass is roughly ten times less than Hiiaka's and about 3,000 times less than Haumea's.
Namaka orbits Haumea about once every 18.3 days, at an average distance of 25,500 km. The orbit is elliptical, with an eccentricity of about 0.22, and tilted roughly 13 degrees relative to Haumea's equator.
Namaka is expected to rotate chaotically because Haumea's tides slow its spin while its eccentric orbit triggers multiple spin-orbit resonances. Simulations suggest its axial tilt and rotation period can shift unpredictably, similar to Saturn's moon Hyperion.
Namaka is believed to have formed from icy material ejected during a giant impact on Haumea about 4.4 billion years ago. A 2022 study led by Jessica Noviello proposed that the moon later coalesced through a process called rotational fissioning, roughly 80 million years after that impact.