The Soft X-Ray Telescope (SXT) modules are the fundamental focusing assemblies on NASA's next major X-ray
telescope mission, the International X-Ray Observatory (IXO). The preliminary design and analysis of these assemblies
has been completed, addressing the major engineering challenges and leading to an understanding of the factors effecting
module performance. Each of the 60 modules in the Flight Mirror Assembly (FMA) supports 200-300 densely packed
0.4 mm thick glass mirror segments in order to meet the unprecedented effective area required to achieve the scientific
objectives of the mission. Detailed Finite Element Analysis (FEA), materials testing, and environmental testing have
been completed to ensure the modules can be successfully launched. Resulting stress margins are positive based on
detailed FEA, a large factor of safety, and a design strength determined by robust characterization of the glass properties.
FEA correlates well with the results of the successful modal, vibration, and acoustic environmental tests. Deformation of
the module due to on-orbit thermal conditions is also a major design driver. A preliminary thermal control system has
been designed and the sensitivity of module optical performance to various thermal loads has been determined using
optomechanical analysis methods developed for this unique assembly. This design and analysis furthers the goal of
building a module that demonstrates the ability to meet IXO requirements, which is the current focus of the IXO FMA
technology development team.