There are mutliple artists with this name:

1) The solo project of former Dismember/Carnage drummer Fred Estby.
2) A Canadian thrash/death/groove metal band, formed in 1997.

1) After more than 20 years in the death metal scene, Estby wanted to express his passion for different kinds of extreme music he’s bore since his youth. In 2008, Estby started to write and record material with the intention of having one unique vocalist for each song. Dubbed NECRONAUT, the project would become a reality one year later when Estby began contacting the many talented metal musicians he had in mind to complete the album of his diabolic dreams. In short, NECRONAUT is a raw slab of old-school metal and while the term “old-school” alone goes a long way in accurately describing the sound that one should expect from Estby and co, NECRONAUT is so much more. The band’s approach is crude and dead simple, a la early Bathory and Venom mutated with Black Sabbath and Iron Maiden, but with an unorthodox bass-heavy production that allows the album to stand out amongst its peers. The goal was primitive brute force, but because of the manner in which Estby chose to achieve it, he also managed to create an aura of pure malevolence that, prior to this album’s creation, was likely difficult to imagine. Read more on Last.fm. User-contributed text is available under the Creative Commons By-SA License; additional terms may apply.