The ECS Bjarni Herjolfsson was a cargo ship owned by the Earth Cargo Authority during the 22nd century. The ship was named after the 10th century Norse explorer Bjarni Herjólfsson, the first known European discoverer of the mainland of the Americas, which he sighted in 985.
At some point prior to 2163, the ship discovered Hansen's Planet. Its captain named the planet after Sven "Buttercup" Hansen, his favourite prize fighter. Its crew had staked a claim to its two dilithium-rich moons but had less interest in the planet for its dilithium deposits were too deeply buried. (ENT - Rise of the Federation novel: A Choice of Futures)