EXPERIMENT BACKGROUND
Current spacecrafts are confined in size due to the lack of volume in current launch vehicles. Deployment of large structures for space applications include such things as antennas, habitats, solar concentrators, sun shades, micro-meteorite shielding, solar sails, and load bearing members. Large structures such as these will be required for the successful advancement of missions in the near future. Recent research by NASA has investigated how Gossamer, light weight, and inflatable structures can be employed as possible solutions for the volume constraint problem in both manned and unmanned spacecrafts [AIAA 2002-1376, AIAA 2001-1417, NASA LRC meeting July 26, 2002]. This type of technology has significant potential for low cost flight hardware, exceptionally high mechanical packaging efficiency, deployment reliability and low weight. One possible deployable structure that NASA and universities have been studying is a thin-film polyurethane foam filled structure. The polyurethane foam begins as two liquid components and when mixed, expands several times its original volume filling the cross section of the structure. The foam can be used to either deploy and/or add rigidity and strength. As such, the structural properties of the deployable structure will depend on the way that the foam develops the cross section, and thus a function of the way the foam expands. An experiment containing Latex and Kapton thin-film deployable structures and different types of polyurethane foam will be taken aboard Johnson Space CenterŐs KC-135. The thin films will be filled with various polyurethane foams in a variety of gravitational environments while in two different orientations. Latex structures, due to their flexibility, should indicate natural expansion behavior while Kapton structures will demonstrate foam behavior in a semi-rigid volume. The polyurethane foams will differ in their expansion ratios and liquid component properties. The expansion ratios will change the expansion rate and the liquid component properties will affect the way the two components mix; both of which will be affected by reduced gravity. The cross section of the structures will then be evaluated on their uniformity, size, and density to observe how various gravitational environments and orientations affect the dispersion and expansion of the foam. The cross sectional observations will provide the necessary insight about the functionality of polyurethane foam expansion for an application in a space based deployable structure.