An oscillating heat pipe that can maintain efficient heat transfer even in a high gravity force equivalent environment is provided. The heat pipe can comprise a condenser region having a first plurality of bends, an evaporator region having a second plurality of bends, and a plurality of intermediate portions. The plurality of intermediate portions can extend between the first plurality of bends and the second plurality of bends. The plurality of intermediate portions can include a first intermediate portion and a second intermediate portion. A cross-sectional area of the first intermediate portion can be larger than a cross-sectional area of the second intermediate portion in a plane at a first distance from the evaporator region. The cross-sectional area of at least one of the first or second intermediate portions can increase from the condenser region towards the evaporator region.