The Cosmonauts Sea is part of..?

Cosmonauts Sea was a proposed sea name as part of the Southern Ocean. It would have an area of 699,000 square kilometres. It would be bordered by, a Cooperation Sea to the east, and to the west a Riiser-Larsen Sea. The Cosmonauts Sea was named in 1962 by the Soviet Antarctic Expedition in honor of the world's first cosmonauts and the beginning of manned space exploration era.