The Capillary Flow Experiments: Handheld Fluids Experiments for International Space Station

NASA is constructing a series of handheld test vessels to study key characteristics of low-g capillary flows aboard the International Space Station (ISS). The Capillary Flow Experiment (CFE) consists of 6 approximately 1 to 2 kg flight units designed to probe certain capillary phenomena of fundamental and applied importance, such as; capillary flow in complex containers, critical wetting in discontinuous structures, and large length scale contact line damping. Quantitative video images from the simply performed flight experiment crew procedures are anticipated to provide immediate confirmation of the usefulness of current analytical design tools as well as provide guidance to the development of new ones. A description of the experiment requirements, flight hardware, and challenging time constraints imposed on the design team is provided for the project to date. The CFE flight experimental program (conception) was initiated in February 2003 as part of a fast-paced unscheduled payloads/experiments program. Two of the flight units are tentatively planned for launch to ISS in Fall, 2003. The experiments will be performed in stand-alone mode by a single crewmember on the Maintenance Work Area of the ISS. The specific experimental objectives are briefly introduced by way of the crew procedures and a sample of the as yet unverified theoretical predictions of the fluid behavior is provided. The potential impact of the flight experiments on the design of spacecraft fluid systems is discussed.