Feature · Science / TechnologyTB 26-08 Complex Modes in Lightly Damped Structural Systems: A Two-Mode Interaction PerspectiveFor more information, contact Joel W. Sills, Langley Research Center, joel.w.sills@nasa.gov Download the PDF version Complex mode shapes can emerge in a linear structure even when overall damping is low. This behavior can occur when two structural modes are closely spaced in frequency and are coupled through nonproportional damping. As the damping interaction increases, the […]Read the full story →Meagan Chappell · October 13, 2026 at 11:02 AM
Feature · Science / TechnologyTB 26-07 Aluminum Alloy 2219 Material GuidanceFor more information, contact Donald S. Parker, Kennedy Space Center, donald.s.parker@nasa.gov Download the PDF version Improper casting and forging processes in the manufacture of aluminum alloy 2219 can lead to microstructural defects that result in a sub-optimal response to anodic surface treatments and an increase in corrosion susceptibility. This Technical Bulletin communicates the risks of […]Read the full story →Meagan Chappell · September 25, 2026 at 10:45 AM
Feature · Science / TechnologyTB 26-06 Risk of Hydrazine Use Following Freeze–Thaw ExposureFor more information, contact Jonathan E. Jones, Langley Research Center, jonathan.e.jones@nasa.gov Download the PDF version The purpose of this Technical Bulletin is to communicate the risks associated with freeze–thaw cycles in hydrazine monopropellant systems and to provide general recommendations for mitigating damage, operational hazards, and loss of system reliability in propulsion and auxiliary hydrazine systems. […]Read the full story →Meagan Chappell · September 23, 2026 at 10:31 AM
