Thermal management systems for space applications based on two phase flow have attractive advantages over single phase systems including reduced mass and increased heat transfer rates. However, before two phase systems for space can be designed effectively, knowledge of two phase flow behavior through real engineering components in reduced gravity is necessary. This work shows typical plots from an experimental study of two phase flow pressure drops through 1.25 m corrugated flexible bellows and quick disconnect attachments in reduced gravity. Three components are examined: a 10.41 mm minimum inner diameter flexible bellows, a 4.7 mm minimum inner diameter flexible bellows, and a quick disconnect apparatus between two 10.41 mm bellows sections. These components were tested simultaneously with a 1.25 m smooth glass tube of identical inner diameter for comparison. The smooth glass tubes were filmed using a digital imager for flow regime determination. These data were obtained from a test package using R12 as the working fluid and flown aboard NASA’s KC‐135. For the data used in these figures, pressure drops in the quick disconnect section increase 30–40% in microgravity, while in both sizes of bellows sections, pressure drops are seen to decrease 10–20%. © 1995American Institute of Physics